add another interface

3 files changed, 582 insertions, 419 deletions

diff --git a/python/src/_cdec.cpp b/python/src/_cdec.cpp
index 6f341f41..00cb0641 100644
--- a/python/src/_cdec.cpp
+++ b/python/src/_cdec.cpp
@@ -1,4 +1,4 @@
-/* Generated by Cython 0.17.1 on Sun Nov 18 14:23:01 2012 */
+/* Generated by Cython 0.17.1 on Sun Nov 18 15:08:18 2012 */
 
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
@@ -588,7 +588,7 @@ struct __pyx_obj_5_cdec___pyx_scope_struct_20_lines {
 };
 
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":103
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":108
  *             del hypos
  * 
  *     def sample_trees(self, unsigned n):             # <<<<<<<<<<<<<<
@@ -606,7 +606,7 @@ struct __pyx_obj_5_cdec___pyx_scope_struct_12_sample_trees {
 };
 
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":156
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":161
  * 
  *     property edges:
  *         def __get__(self):             # <<<<<<<<<<<<<<
@@ -650,7 +650,7 @@ struct __pyx_obj_5_cdec_CandidateSet {
 };
 
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":162
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":167
  * 
  *     property nodes:
  *         def __get__(self):             # <<<<<<<<<<<<<<
@@ -815,7 +815,7 @@ struct __pyx_obj_4cdec_2sa_3_sa_FloatList {
 };
 
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":191
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":196
  *         return vector
  * 
  * cdef class HypergraphEdge:             # <<<<<<<<<<<<<<
@@ -848,7 +848,7 @@ struct __pyx_obj_5_cdec___pyx_scope_struct_1___iter__ {
 };
 
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":247
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":256
  * 
  *     property in_edges:
  *         def __get__(self):             # <<<<<<<<<<<<<<
@@ -911,7 +911,7 @@ struct __pyx_obj_5_cdec_Decoder {
 };
 
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":237
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":246
  *         raise NotImplemented('comparison not implemented for HypergraphEdge')
  * 
  * cdef class HypergraphNode:             # <<<<<<<<<<<<<<
@@ -939,7 +939,7 @@ struct __pyx_obj_5_cdec_SparseVector {
 };
 
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":253
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":262
  * 
  *     property out_edges:
  *         def __get__(self):             # <<<<<<<<<<<<<<
@@ -1048,7 +1048,7 @@ struct __pyx_obj_5_cdec_SufficientStats {
 };
 
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":44
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":49
  *         return unicode(hypergraph.JoshuaVisualizationString(self.hg[0]).c_str(), 'utf8')
  * 
  *     def kbest(self, size):             # <<<<<<<<<<<<<<
@@ -1067,7 +1067,7 @@ struct __pyx_obj_5_cdec___pyx_scope_struct_8_kbest {
 };
 
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":76
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":81
  *             del e_derivations
  * 
  *     def kbest_features(self, size):             # <<<<<<<<<<<<<<
@@ -1087,7 +1087,7 @@ struct __pyx_obj_5_cdec___pyx_scope_struct_10_kbest_features {
 };
 
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":211
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":216
  * 
  *     property tail_nodes:
  *         def __get__(self):             # <<<<<<<<<<<<<<
@@ -1133,7 +1133,7 @@ struct __pyx_obj_5_cdec___pyx_scope_struct_3_genexpr {
 };
 
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":57
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":62
  *             del derivations
  * 
  *     def kbest_trees(self, size):             # <<<<<<<<<<<<<<
@@ -1184,7 +1184,7 @@ struct __pyx_obj_5_cdec_Lattice {
 };
 
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":92
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":97
  *             del derivations
  * 
  *     def sample(self, unsigned n):             # <<<<<<<<<<<<<<
@@ -1252,7 +1252,7 @@ struct __pyx_vtabstruct_5_cdec_Hypergraph {
 static struct __pyx_vtabstruct_5_cdec_Hypergraph *__pyx_vtabptr_5_cdec_Hypergraph;
 
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":191
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":196
  *         return vector
  * 
  * cdef class HypergraphEdge:             # <<<<<<<<<<<<<<
@@ -1317,7 +1317,7 @@ struct __pyx_vtabstruct_4cdec_2sa_3_sa_Phrase {
 static struct __pyx_vtabstruct_4cdec_2sa_3_sa_Phrase *__pyx_vtabptr_4cdec_2sa_3_sa_Phrase;
 
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":237
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":246
  *         raise NotImplemented('comparison not implemented for HypergraphEdge')
  * 
  * cdef class HypergraphNode:             # <<<<<<<<<<<<<<
@@ -1917,26 +1917,28 @@ static void __pyx_pf_5_cdec_10Hypergraph___dealloc__(struct __pyx_obj_5_cdec_Hyp
 static PyObject *__pyx_pf_5_cdec_10Hypergraph_2viterbi(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_5_cdec_10Hypergraph_4viterbi_trees(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_5_cdec_10Hypergraph_6viterbi_features(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_8viterbi_joshua(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_10kbest(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_size); /* proto */
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_13kbest_trees(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_size); /* proto */
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_16kbest_features(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_size); /* proto */
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_19sample(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, unsigned int __pyx_v_n); /* proto */
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_22sample_trees(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, unsigned int __pyx_v_n); /* proto */
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_25intersect(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_inp); /* proto */
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_27prune(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_beam_alpha, PyObject *__pyx_v_density, PyObject *__pyx_v_kwargs); /* proto */
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_29lattice(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_31plf(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_33reweight(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_weights); /* proto */
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_8viterbi_forest(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_10viterbi_joshua(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_12kbest(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_size); /* proto */
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_15kbest_trees(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_size); /* proto */
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_18kbest_features(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_size); /* proto */
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_21sample(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, unsigned int __pyx_v_n); /* proto */
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_24sample_trees(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, unsigned int __pyx_v_n); /* proto */
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_27intersect(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_inp); /* proto */
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_29prune(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_beam_alpha, PyObject *__pyx_v_density, PyObject *__pyx_v_kwargs); /* proto */
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_31lattice(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_33plf(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_35reweight(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_weights); /* proto */
 static PyObject *__pyx_pf_5_cdec_10Hypergraph_5edges___get__(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_5_cdec_10Hypergraph_5nodes___get__(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_5_cdec_10Hypergraph_4goal___get__(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_5_cdec_10Hypergraph_6npaths___get__(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_35inside_outside(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_37inside_outside(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
 static Py_ssize_t __pyx_pf_5_cdec_14HypergraphEdge___len__(struct __pyx_obj_5_cdec_HypergraphEdge *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_5_cdec_14HypergraphEdge_9head_node___get__(struct __pyx_obj_5_cdec_HypergraphEdge *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_5_cdec_14HypergraphEdge_10tail_nodes___get__(struct __pyx_obj_5_cdec_HypergraphEdge *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_5_cdec_14HypergraphEdge_4span___get__(struct __pyx_obj_5_cdec_HypergraphEdge *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_5_cdec_14HypergraphEdge_8src_span___get__(struct __pyx_obj_5_cdec_HypergraphEdge *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_5_cdec_14HypergraphEdge_14feature_values___get__(struct __pyx_obj_5_cdec_HypergraphEdge *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_5_cdec_14HypergraphEdge_4prob___get__(struct __pyx_obj_5_cdec_HypergraphEdge *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_5_cdec_14HypergraphEdge_2__richcmp__(struct __pyx_obj_5_cdec_HypergraphEdge *__pyx_v_x, struct __pyx_obj_5_cdec_HypergraphEdge *__pyx_v_y, int __pyx_v_op); /* proto */
@@ -9078,7 +9080,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_6viterbi_features(struct __pyx_obj
  *         fmap.vector = new FastSparseVector[weight_t](hypergraph.ViterbiFeatures(self.hg[0]))
  *         return fmap             # <<<<<<<<<<<<<<
  * 
- *     def viterbi_joshua(self):
+ *     def viterbi_forest(self):
  */
   __Pyx_XDECREF(__pyx_r);
   __Pyx_INCREF(((PyObject *)__pyx_v_fmap));
@@ -9099,13 +9101,12 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_6viterbi_features(struct __pyx_obj
 }
 
 /* Python wrapper */
-static PyObject *__pyx_pw_5_cdec_10Hypergraph_9viterbi_joshua(PyObject *__pyx_v_self, CYTHON_UNUSED PyObject *unused); /*proto*/
-static char __pyx_doc_5_cdec_10Hypergraph_8viterbi_joshua[] = "hg.viterbi_joshua() -> Joshua representation of the best derivation.";
-static PyObject *__pyx_pw_5_cdec_10Hypergraph_9viterbi_joshua(PyObject *__pyx_v_self, CYTHON_UNUSED PyObject *unused) {
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_9viterbi_forest(PyObject *__pyx_v_self, CYTHON_UNUSED PyObject *unused); /*proto*/
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_9viterbi_forest(PyObject *__pyx_v_self, CYTHON_UNUSED PyObject *unused) {
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   __Pyx_RefNannyDeclarations
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+  __Pyx_RefNannySetupContext("viterbi_forest (wrapper)", 0);
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   __Pyx_RefNannyFinishContext();
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@@ -9113,12 +9114,88 @@ static PyObject *__pyx_pw_5_cdec_10Hypergraph_9viterbi_joshua(PyObject *__pyx_v_
 /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":40
  *         return fmap
  * 
+ *     def viterbi_forest(self):             # <<<<<<<<<<<<<<
+ *         cdef Hypergraph hg = Hypergraph()
+ *         hg.hg = new hypergraph.Hypergraph(self.hg[0].CreateViterbiHypergraph(NULL).get()[0])
+ */
+
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_8viterbi_forest(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self) {
+  struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_hg = 0;
+  PyObject *__pyx_r = NULL;
+  __Pyx_RefNannyDeclarations
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+
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":41
+ * 
+ *     def viterbi_forest(self):
+ *         cdef Hypergraph hg = Hypergraph()             # <<<<<<<<<<<<<<
+ *         hg.hg = new hypergraph.Hypergraph(self.hg[0].CreateViterbiHypergraph(NULL).get()[0])
+ *         return hg
+ */
+  __pyx_t_1 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_Hypergraph)), ((PyObject *)__pyx_empty_tuple), NULL); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 41; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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+  __pyx_t_1 = 0;
+
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":42
+ *     def viterbi_forest(self):
+ *         cdef Hypergraph hg = Hypergraph()
+ *         hg.hg = new hypergraph.Hypergraph(self.hg[0].CreateViterbiHypergraph(NULL).get()[0])             # <<<<<<<<<<<<<<
+ *         return hg
+ * 
+ */
+  __pyx_v_hg->hg = new Hypergraph(((__pyx_v_self->hg[0]).CreateViterbiHypergraph(NULL).get()[0]));
+
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":43
+ *         cdef Hypergraph hg = Hypergraph()
+ *         hg.hg = new hypergraph.Hypergraph(self.hg[0].CreateViterbiHypergraph(NULL).get()[0])
+ *         return hg             # <<<<<<<<<<<<<<
+ * 
+ *     def viterbi_joshua(self):
+ */
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+  __Pyx_INCREF(((PyObject *)__pyx_v_hg));
+  __pyx_r = ((PyObject *)__pyx_v_hg);
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+  __pyx_r = Py_None; __Pyx_INCREF(Py_None);
+  goto __pyx_L0;
+  __pyx_L1_error:;
+  __Pyx_XDECREF(__pyx_t_1);
+  __Pyx_AddTraceback("_cdec.Hypergraph.viterbi_forest", __pyx_clineno, __pyx_lineno, __pyx_filename);
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+}
+
+/* Python wrapper */
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_11viterbi_joshua(PyObject *__pyx_v_self, CYTHON_UNUSED PyObject *unused); /*proto*/
+static char __pyx_doc_5_cdec_10Hypergraph_10viterbi_joshua[] = "hg.viterbi_joshua() -> Joshua representation of the best derivation.";
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_11viterbi_joshua(PyObject *__pyx_v_self, CYTHON_UNUSED PyObject *unused) {
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+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":45
+ *         return hg
+ * 
  *     def viterbi_joshua(self):             # <<<<<<<<<<<<<<
  *         """hg.viterbi_joshua() -> Joshua representation of the best derivation."""
  *         return unicode(hypergraph.JoshuaVisualizationString(self.hg[0]).c_str(), 'utf8')
  */
 
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_8viterbi_joshua(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self) {
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_10viterbi_joshua(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self) {
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@@ -9128,7 +9205,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_8viterbi_joshua(struct __pyx_obj_5
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":42
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":47
  *     def viterbi_joshua(self):
  *         """hg.viterbi_joshua() -> Joshua representation of the best derivation."""
  *         return unicode(hypergraph.JoshuaVisualizationString(self.hg[0]).c_str(), 'utf8')             # <<<<<<<<<<<<<<
@@ -9136,9 +9213,9 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_8viterbi_joshua(struct __pyx_obj_5
  *     def kbest(self, size):
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+  __pyx_t_1 = PyBytes_FromString(JoshuaVisualizationString((__pyx_v_self->hg[0])).c_str()); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 47; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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   __pyx_r = __pyx_t_1;
@@ -9165,21 +9242,21 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_8viterbi_joshua(struct __pyx_obj_5
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 }
-static PyObject *__pyx_gb_5_cdec_10Hypergraph_12generator4(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value); /* proto */
+static PyObject *__pyx_gb_5_cdec_10Hypergraph_14generator4(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value); /* proto */
 
 /* Python wrapper */
-static PyObject *__pyx_pw_5_cdec_10Hypergraph_11kbest(PyObject *__pyx_v_self, PyObject *__pyx_v_size); /*proto*/
-static char __pyx_doc_5_cdec_10Hypergraph_10kbest[] = "hg.kbest(size) -> List of k-best hypotheses in the hypergraph.";
-static PyObject *__pyx_pw_5_cdec_10Hypergraph_11kbest(PyObject *__pyx_v_self, PyObject *__pyx_v_size) {
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_13kbest(PyObject *__pyx_v_self, PyObject *__pyx_v_size); /*proto*/
+static char __pyx_doc_5_cdec_10Hypergraph_12kbest[] = "hg.kbest(size) -> List of k-best hypotheses in the hypergraph.";
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_13kbest(PyObject *__pyx_v_self, PyObject *__pyx_v_size) {
   PyObject *__pyx_r = 0;
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   __Pyx_RefNannySetupContext("kbest (wrapper)", 0);
-  __pyx_r = __pyx_pf_5_cdec_10Hypergraph_10kbest(((struct __pyx_obj_5_cdec_Hypergraph *)__pyx_v_self), ((PyObject *)__pyx_v_size));
+  __pyx_r = __pyx_pf_5_cdec_10Hypergraph_12kbest(((struct __pyx_obj_5_cdec_Hypergraph *)__pyx_v_self), ((PyObject *)__pyx_v_size));
   __Pyx_RefNannyFinishContext();
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-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":44
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":49
  *         return unicode(hypergraph.JoshuaVisualizationString(self.hg[0]).c_str(), 'utf8')
  * 
  *     def kbest(self, size):             # <<<<<<<<<<<<<<
@@ -9187,7 +9264,7 @@ static PyObject *__pyx_pw_5_cdec_10Hypergraph_11kbest(PyObject *__pyx_v_self, Py
  *         cdef kbest.KBestDerivations[vector[WordID], kbest.ESentenceTraversal]* derivations = new kbest.KBestDerivations[vector[WordID], kbest.ESentenceTraversal](self.hg[0], size)
  */
 
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_10kbest(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_size) {
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_12kbest(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_size) {
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@@ -9208,7 +9285,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_10kbest(struct __pyx_obj_5_cdec_Hy
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   __Pyx_GIVEREF(__pyx_cur_scope->__pyx_v_size);
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+    __pyx_GeneratorObject *gen = __Pyx_Generator_New((__pyx_generator_body_t) __pyx_gb_5_cdec_10Hypergraph_14generator4, (PyObject *) __pyx_cur_scope); if (unlikely(!gen)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 49; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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@@ -9226,7 +9303,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_10kbest(struct __pyx_obj_5_cdec_Hy
   return __pyx_r;
 }
 
-static PyObject *__pyx_gb_5_cdec_10Hypergraph_12generator4(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value) /* generator body */
+static PyObject *__pyx_gb_5_cdec_10Hypergraph_14generator4(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value) /* generator body */
 {
   struct __pyx_obj_5_cdec___pyx_scope_struct_8_kbest *__pyx_cur_scope = ((struct __pyx_obj_5_cdec___pyx_scope_struct_8_kbest *)__pyx_generator->closure);
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@@ -9245,19 +9322,19 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_12generator4(__pyx_GeneratorObject
     return NULL;
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-  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 44; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 49; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":46
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":51
  *     def kbest(self, size):
  *         """hg.kbest(size) -> List of k-best hypotheses in the hypergraph."""
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  *         cdef unsigned k
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-  __pyx_t_1 = __Pyx_PyInt_AsUnsignedInt(__pyx_cur_scope->__pyx_v_size); if (unlikely((__pyx_t_1 == (unsigned int)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 46; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_t_1 = __Pyx_PyInt_AsUnsignedInt(__pyx_cur_scope->__pyx_v_size); if (unlikely((__pyx_t_1 == (unsigned int)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 51; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_cur_scope->__pyx_v_derivations = new KBest::KBestDerivations<std::vector<WordID>,ESentenceTraversal>((__pyx_cur_scope->__pyx_v_self->hg[0]), __pyx_t_1);
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":49
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":54
  *         cdef kbest.KBestDerivations[vector[WordID], kbest.ESentenceTraversal].Derivation* derivation
  *         cdef unsigned k
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@@ -9266,18 +9343,18 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_12generator4(__pyx_GeneratorObject
  */
   /*try:*/ {
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":50
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":55
  *         cdef unsigned k
  *         try:
  *             for k in range(size):             # <<<<<<<<<<<<<<
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-    __pyx_t_2 = __Pyx_PyInt_AsLong(__pyx_cur_scope->__pyx_v_size); if (unlikely((__pyx_t_2 == (long)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 50; __pyx_clineno = __LINE__; goto __pyx_L5;}
+    __pyx_t_2 = __Pyx_PyInt_AsLong(__pyx_cur_scope->__pyx_v_size); if (unlikely((__pyx_t_2 == (long)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 55; __pyx_clineno = __LINE__; goto __pyx_L5;}
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       __pyx_cur_scope->__pyx_v_k = __pyx_t_1;
 
-      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":51
+      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":56
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@@ -9286,7 +9363,7 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_12generator4(__pyx_GeneratorObject
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-      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":52
+      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":57
  *             for k in range(size):
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  *                 if not derivation: break             # <<<<<<<<<<<<<<
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-      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":53
+      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":58
  *                 derivation = derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
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  *                 yield unicode(GetString(derivation._yield).c_str(), 'utf8')             # <<<<<<<<<<<<<<
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  *             del derivations
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+      __pyx_t_4 = PyBytes_FromString(TD::GetString(__pyx_cur_scope->__pyx_v_derivation->yield).c_str()); if (unlikely(!__pyx_t_4)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 58; __pyx_clineno = __LINE__; goto __pyx_L5;}
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-      __pyx_t_5 = PyTuple_New(2); if (unlikely(!__pyx_t_5)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 53; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      __pyx_t_5 = PyTuple_New(2); if (unlikely(!__pyx_t_5)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 58; __pyx_clineno = __LINE__; goto __pyx_L5;}
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       PyTuple_SET_ITEM(__pyx_t_5, 0, ((PyObject *)__pyx_t_4));
       __Pyx_GIVEREF(((PyObject *)__pyx_t_4));
@@ -9317,7 +9394,7 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_12generator4(__pyx_GeneratorObject
       PyTuple_SET_ITEM(__pyx_t_5, 1, ((PyObject *)__pyx_n_s__utf8));
       __Pyx_GIVEREF(((PyObject *)__pyx_n_s__utf8));
       __pyx_t_4 = 0;
-      __pyx_t_4 = PyObject_Call(((PyObject *)((PyObject*)(&PyUnicode_Type))), ((PyObject *)__pyx_t_5), NULL); if (unlikely(!__pyx_t_4)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 53; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      __pyx_t_4 = PyObject_Call(((PyObject *)((PyObject*)(&PyUnicode_Type))), ((PyObject *)__pyx_t_5), NULL); if (unlikely(!__pyx_t_4)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 58; __pyx_clineno = __LINE__; goto __pyx_L5;}
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@@ -9332,12 +9409,12 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_12generator4(__pyx_GeneratorObject
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       __pyx_t_1 = __pyx_cur_scope->__pyx_t_0;
       __pyx_t_2 = __pyx_cur_scope->__pyx_t_1;
-      if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 53; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 58; __pyx_clineno = __LINE__; goto __pyx_L5;}
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":55
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":60
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  *         finally:
  *             del derivations             # <<<<<<<<<<<<<<
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-static PyObject *__pyx_gb_5_cdec_10Hypergraph_15generator5(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value); /* proto */
+static PyObject *__pyx_gb_5_cdec_10Hypergraph_17generator5(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value); /* proto */
 
 /* Python wrapper */
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-static PyObject *__pyx_pw_5_cdec_10Hypergraph_14kbest_trees(PyObject *__pyx_v_self, PyObject *__pyx_v_size) {
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_16kbest_trees(PyObject *__pyx_v_self, PyObject *__pyx_v_size); /*proto*/
+static char __pyx_doc_5_cdec_10Hypergraph_15kbest_trees[] = "hg.kbest_trees(size) -> List of k-best trees in the hypergraph.";
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_16kbest_trees(PyObject *__pyx_v_self, PyObject *__pyx_v_size) {
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   __Pyx_RefNannySetupContext("kbest_trees (wrapper)", 0);
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+  __pyx_r = __pyx_pf_5_cdec_10Hypergraph_15kbest_trees(((struct __pyx_obj_5_cdec_Hypergraph *)__pyx_v_self), ((PyObject *)__pyx_v_size));
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-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":57
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":62
  *             del derivations
  * 
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  *         cdef kbest.KBestDerivations[vector[WordID], kbest.FTreeTraversal]* f_derivations = new kbest.KBestDerivations[vector[WordID], kbest.FTreeTraversal](self.hg[0], size)
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-static PyObject *__pyx_pf_5_cdec_10Hypergraph_13kbest_trees(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_size) {
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_15kbest_trees(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_size) {
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@@ -9427,7 +9504,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_13kbest_trees(struct __pyx_obj_5_c
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+    __pyx_GeneratorObject *gen = __Pyx_Generator_New((__pyx_generator_body_t) __pyx_gb_5_cdec_10Hypergraph_17generator5, (PyObject *) __pyx_cur_scope); if (unlikely(!gen)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 62; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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@@ -9445,7 +9522,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_13kbest_trees(struct __pyx_obj_5_c
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 }
 
-static PyObject *__pyx_gb_5_cdec_10Hypergraph_15generator5(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value) /* generator body */
+static PyObject *__pyx_gb_5_cdec_10Hypergraph_17generator5(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value) /* generator body */
 {
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@@ -9466,29 +9543,29 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_15generator5(__pyx_GeneratorObject
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-  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 57; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 62; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":59
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":64
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-  __pyx_t_1 = __Pyx_PyInt_AsUnsignedInt(__pyx_cur_scope->__pyx_v_size); if (unlikely((__pyx_t_1 == (unsigned int)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 59; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_t_1 = __Pyx_PyInt_AsUnsignedInt(__pyx_cur_scope->__pyx_v_size); if (unlikely((__pyx_t_1 == (unsigned int)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 64; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":61
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":66
  *         cdef kbest.KBestDerivations[vector[WordID], kbest.FTreeTraversal]* f_derivations = new kbest.KBestDerivations[vector[WordID], kbest.FTreeTraversal](self.hg[0], size)
  *         cdef kbest.KBestDerivations[vector[WordID], kbest.FTreeTraversal].Derivation* f_derivation
  *         cdef kbest.KBestDerivations[vector[WordID], kbest.ETreeTraversal]* e_derivations = new kbest.KBestDerivations[vector[WordID], kbest.ETreeTraversal](self.hg[0], size)             # <<<<<<<<<<<<<<
  *         cdef kbest.KBestDerivations[vector[WordID], kbest.ETreeTraversal].Derivation* e_derivation
  *         cdef unsigned k
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-  __pyx_t_1 = __Pyx_PyInt_AsUnsignedInt(__pyx_cur_scope->__pyx_v_size); if (unlikely((__pyx_t_1 == (unsigned int)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 61; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_t_1 = __Pyx_PyInt_AsUnsignedInt(__pyx_cur_scope->__pyx_v_size); if (unlikely((__pyx_t_1 == (unsigned int)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 66; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_cur_scope->__pyx_v_e_derivations = new KBest::KBestDerivations<std::vector<WordID>,ETreeTraversal>((__pyx_cur_scope->__pyx_v_self->hg[0]), __pyx_t_1);
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":64
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":69
  *         cdef kbest.KBestDerivations[vector[WordID], kbest.ETreeTraversal].Derivation* e_derivation
  *         cdef unsigned k
  *         try:             # <<<<<<<<<<<<<<
@@ -9497,18 +9574,18 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_15generator5(__pyx_GeneratorObject
  */
   /*try:*/ {
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":65
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":70
  *         cdef unsigned k
  *         try:
  *             for k in range(size):             # <<<<<<<<<<<<<<
  *                 f_derivation = f_derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
  *                 e_derivation = e_derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
  */
-    __pyx_t_2 = __Pyx_PyInt_AsLong(__pyx_cur_scope->__pyx_v_size); if (unlikely((__pyx_t_2 == (long)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 65; __pyx_clineno = __LINE__; goto __pyx_L5;}
+    __pyx_t_2 = __Pyx_PyInt_AsLong(__pyx_cur_scope->__pyx_v_size); if (unlikely((__pyx_t_2 == (long)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 70; __pyx_clineno = __LINE__; goto __pyx_L5;}
     for (__pyx_t_1 = 0; __pyx_t_1 < __pyx_t_2; __pyx_t_1+=1) {
       __pyx_cur_scope->__pyx_v_k = __pyx_t_1;
 
-      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":66
+      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":71
  *         try:
  *             for k in range(size):
  *                 f_derivation = f_derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)             # <<<<<<<<<<<<<<
@@ -9517,7 +9594,7 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_15generator5(__pyx_GeneratorObject
  */
       __pyx_cur_scope->__pyx_v_f_derivation = __pyx_cur_scope->__pyx_v_f_derivations->LazyKthBest((__pyx_cur_scope->__pyx_v_self->hg->nodes_.size() - 1), __pyx_cur_scope->__pyx_v_k);
 
-      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":67
+      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":72
  *             for k in range(size):
  *                 f_derivation = f_derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
  *                 e_derivation = e_derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)             # <<<<<<<<<<<<<<
@@ -9526,7 +9603,7 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_15generator5(__pyx_GeneratorObject
  */
       __pyx_cur_scope->__pyx_v_e_derivation = __pyx_cur_scope->__pyx_v_e_derivations->LazyKthBest((__pyx_cur_scope->__pyx_v_self->hg->nodes_.size() - 1), __pyx_cur_scope->__pyx_v_k);
 
-      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":68
+      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":73
  *                 f_derivation = f_derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
  *                 e_derivation = e_derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
  *                 if not f_derivation or not e_derivation: break             # <<<<<<<<<<<<<<
@@ -9546,16 +9623,16 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_15generator5(__pyx_GeneratorObject
       }
       __pyx_L9:;
 
-      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":69
+      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":74
  *                 e_derivation = e_derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
  *                 if not f_derivation or not e_derivation: break
  *                 f_tree = unicode(GetString(f_derivation._yield).c_str(), 'utf8')             # <<<<<<<<<<<<<<
  *                 e_tree = unicode(GetString(e_derivation._yield).c_str(), 'utf8')
  *                 yield (f_tree, e_tree)
  */
-      __pyx_t_6 = PyBytes_FromString(TD::GetString(__pyx_cur_scope->__pyx_v_f_derivation->yield).c_str()); if (unlikely(!__pyx_t_6)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 69; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      __pyx_t_6 = PyBytes_FromString(TD::GetString(__pyx_cur_scope->__pyx_v_f_derivation->yield).c_str()); if (unlikely(!__pyx_t_6)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 74; __pyx_clineno = __LINE__; goto __pyx_L5;}
       __Pyx_GOTREF(((PyObject *)__pyx_t_6));
-      __pyx_t_7 = PyTuple_New(2); if (unlikely(!__pyx_t_7)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 69; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      __pyx_t_7 = PyTuple_New(2); if (unlikely(!__pyx_t_7)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 74; __pyx_clineno = __LINE__; goto __pyx_L5;}
       __Pyx_GOTREF(__pyx_t_7);
       PyTuple_SET_ITEM(__pyx_t_7, 0, ((PyObject *)__pyx_t_6));
       __Pyx_GIVEREF(((PyObject *)__pyx_t_6));
@@ -9563,7 +9640,7 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_15generator5(__pyx_GeneratorObject
       PyTuple_SET_ITEM(__pyx_t_7, 1, ((PyObject *)__pyx_n_s__utf8));
       __Pyx_GIVEREF(((PyObject *)__pyx_n_s__utf8));
       __pyx_t_6 = 0;
-      __pyx_t_6 = PyObject_Call(((PyObject *)((PyObject*)(&PyUnicode_Type))), ((PyObject *)__pyx_t_7), NULL); if (unlikely(!__pyx_t_6)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 69; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      __pyx_t_6 = PyObject_Call(((PyObject *)((PyObject*)(&PyUnicode_Type))), ((PyObject *)__pyx_t_7), NULL); if (unlikely(!__pyx_t_6)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 74; __pyx_clineno = __LINE__; goto __pyx_L5;}
       __Pyx_GOTREF(__pyx_t_6);
       __Pyx_DECREF(((PyObject *)__pyx_t_7)); __pyx_t_7 = 0;
       __Pyx_XGOTREF(((PyObject *)__pyx_cur_scope->__pyx_v_f_tree));
@@ -9572,16 +9649,16 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_15generator5(__pyx_GeneratorObject
       __pyx_cur_scope->__pyx_v_f_tree = ((PyObject*)__pyx_t_6);
       __pyx_t_6 = 0;
 
-      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":70
+      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":75
  *                 if not f_derivation or not e_derivation: break
  *                 f_tree = unicode(GetString(f_derivation._yield).c_str(), 'utf8')
  *                 e_tree = unicode(GetString(e_derivation._yield).c_str(), 'utf8')             # <<<<<<<<<<<<<<
  *                 yield (f_tree, e_tree)
  *         finally:
  */
-      __pyx_t_6 = PyBytes_FromString(TD::GetString(__pyx_cur_scope->__pyx_v_e_derivation->yield).c_str()); if (unlikely(!__pyx_t_6)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 70; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      __pyx_t_6 = PyBytes_FromString(TD::GetString(__pyx_cur_scope->__pyx_v_e_derivation->yield).c_str()); if (unlikely(!__pyx_t_6)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 75; __pyx_clineno = __LINE__; goto __pyx_L5;}
       __Pyx_GOTREF(((PyObject *)__pyx_t_6));
-      __pyx_t_7 = PyTuple_New(2); if (unlikely(!__pyx_t_7)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 70; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      __pyx_t_7 = PyTuple_New(2); if (unlikely(!__pyx_t_7)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 75; __pyx_clineno = __LINE__; goto __pyx_L5;}
       __Pyx_GOTREF(__pyx_t_7);
       PyTuple_SET_ITEM(__pyx_t_7, 0, ((PyObject *)__pyx_t_6));
       __Pyx_GIVEREF(((PyObject *)__pyx_t_6));
@@ -9589,7 +9666,7 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_15generator5(__pyx_GeneratorObject
       PyTuple_SET_ITEM(__pyx_t_7, 1, ((PyObject *)__pyx_n_s__utf8));
       __Pyx_GIVEREF(((PyObject *)__pyx_n_s__utf8));
       __pyx_t_6 = 0;
-      __pyx_t_6 = PyObject_Call(((PyObject *)((PyObject*)(&PyUnicode_Type))), ((PyObject *)__pyx_t_7), NULL); if (unlikely(!__pyx_t_6)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 70; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      __pyx_t_6 = PyObject_Call(((PyObject *)((PyObject*)(&PyUnicode_Type))), ((PyObject *)__pyx_t_7), NULL); if (unlikely(!__pyx_t_6)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 75; __pyx_clineno = __LINE__; goto __pyx_L5;}
       __Pyx_GOTREF(__pyx_t_6);
       __Pyx_DECREF(((PyObject *)__pyx_t_7)); __pyx_t_7 = 0;
       __Pyx_XGOTREF(((PyObject *)__pyx_cur_scope->__pyx_v_e_tree));
@@ -9598,14 +9675,14 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_15generator5(__pyx_GeneratorObject
       __pyx_cur_scope->__pyx_v_e_tree = ((PyObject*)__pyx_t_6);
       __pyx_t_6 = 0;
 
-      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":71
+      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":76
  *                 f_tree = unicode(GetString(f_derivation._yield).c_str(), 'utf8')
  *                 e_tree = unicode(GetString(e_derivation._yield).c_str(), 'utf8')
  *                 yield (f_tree, e_tree)             # <<<<<<<<<<<<<<
  *         finally:
  *             del f_derivations
  */
-      __pyx_t_6 = PyTuple_New(2); if (unlikely(!__pyx_t_6)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 71; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      __pyx_t_6 = PyTuple_New(2); if (unlikely(!__pyx_t_6)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 76; __pyx_clineno = __LINE__; goto __pyx_L5;}
       __Pyx_GOTREF(__pyx_t_6);
       __Pyx_INCREF(((PyObject *)__pyx_cur_scope->__pyx_v_f_tree));
       PyTuple_SET_ITEM(__pyx_t_6, 0, ((PyObject *)__pyx_cur_scope->__pyx_v_f_tree));
@@ -9625,12 +9702,12 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_15generator5(__pyx_GeneratorObject
       __pyx_L10_resume_from_yield:;
       __pyx_t_1 = __pyx_cur_scope->__pyx_t_0;
       __pyx_t_2 = __pyx_cur_scope->__pyx_t_1;
-      if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 71; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 76; __pyx_clineno = __LINE__; goto __pyx_L5;}
     }
     __pyx_L8_break:;
   }
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":73
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":78
  *                 yield (f_tree, e_tree)
  *         finally:
  *             del f_derivations             # <<<<<<<<<<<<<<
@@ -9654,7 +9731,7 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_15generator5(__pyx_GeneratorObject
     __pyx_L6:;
     delete __pyx_cur_scope->__pyx_v_f_derivations;
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":74
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":79
  *         finally:
  *             del f_derivations
  *             del e_derivations             # <<<<<<<<<<<<<<
@@ -9686,21 +9763,21 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_15generator5(__pyx_GeneratorObject
   __Pyx_RefNannyFinishContext();
   return NULL;
 }
-static PyObject *__pyx_gb_5_cdec_10Hypergraph_18generator6(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value); /* proto */
+static PyObject *__pyx_gb_5_cdec_10Hypergraph_20generator6(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value); /* proto */
 
 /* Python wrapper */
-static PyObject *__pyx_pw_5_cdec_10Hypergraph_17kbest_features(PyObject *__pyx_v_self, PyObject *__pyx_v_size); /*proto*/
-static char __pyx_doc_5_cdec_10Hypergraph_16kbest_features[] = "hg.kbest_trees(size) -> List of k-best feature vectors in the hypergraph.";
-static PyObject *__pyx_pw_5_cdec_10Hypergraph_17kbest_features(PyObject *__pyx_v_self, PyObject *__pyx_v_size) {
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_19kbest_features(PyObject *__pyx_v_self, PyObject *__pyx_v_size); /*proto*/
+static char __pyx_doc_5_cdec_10Hypergraph_18kbest_features[] = "hg.kbest_trees(size) -> List of k-best feature vectors in the hypergraph.";
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_19kbest_features(PyObject *__pyx_v_self, PyObject *__pyx_v_size) {
   PyObject *__pyx_r = 0;
   __Pyx_RefNannyDeclarations
   __Pyx_RefNannySetupContext("kbest_features (wrapper)", 0);
-  __pyx_r = __pyx_pf_5_cdec_10Hypergraph_16kbest_features(((struct __pyx_obj_5_cdec_Hypergraph *)__pyx_v_self), ((PyObject *)__pyx_v_size));
+  __pyx_r = __pyx_pf_5_cdec_10Hypergraph_18kbest_features(((struct __pyx_obj_5_cdec_Hypergraph *)__pyx_v_self), ((PyObject *)__pyx_v_size));
   __Pyx_RefNannyFinishContext();
   return __pyx_r;
 }
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":76
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":81
  *             del e_derivations
  * 
  *     def kbest_features(self, size):             # <<<<<<<<<<<<<<
@@ -9708,7 +9785,7 @@ static PyObject *__pyx_pw_5_cdec_10Hypergraph_17kbest_features(PyObject *__pyx_v
  *         cdef kbest.KBestDerivations[FastSparseVector[weight_t], kbest.FeatureVectorTraversal]* derivations = new kbest.KBestDerivations[FastSparseVector[weight_t], kbest.FeatureVectorTraversal](self.hg[0], size)
  */
 
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_16kbest_features(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_size) {
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_18kbest_features(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_size) {
   struct __pyx_obj_5_cdec___pyx_scope_struct_10_kbest_features *__pyx_cur_scope;
   PyObject *__pyx_r = NULL;
   __Pyx_RefNannyDeclarations
@@ -9729,7 +9806,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_16kbest_features(struct __pyx_obj_
   __Pyx_INCREF(__pyx_cur_scope->__pyx_v_size);
   __Pyx_GIVEREF(__pyx_cur_scope->__pyx_v_size);
   {
-    __pyx_GeneratorObject *gen = __Pyx_Generator_New((__pyx_generator_body_t) __pyx_gb_5_cdec_10Hypergraph_18generator6, (PyObject *) __pyx_cur_scope); if (unlikely(!gen)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 76; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    __pyx_GeneratorObject *gen = __Pyx_Generator_New((__pyx_generator_body_t) __pyx_gb_5_cdec_10Hypergraph_20generator6, (PyObject *) __pyx_cur_scope); if (unlikely(!gen)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 81; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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     __Pyx_RefNannyFinishContext();
     return (PyObject *) gen;
@@ -9747,7 +9824,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_16kbest_features(struct __pyx_obj_
   return __pyx_r;
 }
 
-static PyObject *__pyx_gb_5_cdec_10Hypergraph_18generator6(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value) /* generator body */
+static PyObject *__pyx_gb_5_cdec_10Hypergraph_20generator6(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value) /* generator body */
 {
   struct __pyx_obj_5_cdec___pyx_scope_struct_10_kbest_features *__pyx_cur_scope = ((struct __pyx_obj_5_cdec___pyx_scope_struct_10_kbest_features *)__pyx_generator->closure);
   PyObject *__pyx_r = NULL;
@@ -9765,19 +9842,19 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_18generator6(__pyx_GeneratorObject
     return NULL;
   }
   __pyx_L3_first_run:;
-  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 76; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 81; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":78
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":83
  *     def kbest_features(self, size):
  *         """hg.kbest_trees(size) -> List of k-best feature vectors in the hypergraph."""
  *         cdef kbest.KBestDerivations[FastSparseVector[weight_t], kbest.FeatureVectorTraversal]* derivations = new kbest.KBestDerivations[FastSparseVector[weight_t], kbest.FeatureVectorTraversal](self.hg[0], size)             # <<<<<<<<<<<<<<
  *         cdef kbest.KBestDerivations[FastSparseVector[weight_t], kbest.FeatureVectorTraversal].Derivation* derivation
  *         cdef SparseVector fmap
  */
-  __pyx_t_1 = __Pyx_PyInt_AsUnsignedInt(__pyx_cur_scope->__pyx_v_size); if (unlikely((__pyx_t_1 == (unsigned int)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 78; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_t_1 = __Pyx_PyInt_AsUnsignedInt(__pyx_cur_scope->__pyx_v_size); if (unlikely((__pyx_t_1 == (unsigned int)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 83; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_cur_scope->__pyx_v_derivations = new KBest::KBestDerivations<FastSparseVector<weight_t>,FeatureVectorTraversal>((__pyx_cur_scope->__pyx_v_self->hg[0]), __pyx_t_1);
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":82
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":87
  *         cdef SparseVector fmap
  *         cdef unsigned k
  *         try:             # <<<<<<<<<<<<<<
@@ -9786,18 +9863,18 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_18generator6(__pyx_GeneratorObject
  */
   /*try:*/ {
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":83
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":88
  *         cdef unsigned k
  *         try:
  *             for k in range(size):             # <<<<<<<<<<<<<<
  *                 derivation = derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
  *                 if not derivation: break
  */
-    __pyx_t_2 = __Pyx_PyInt_AsLong(__pyx_cur_scope->__pyx_v_size); if (unlikely((__pyx_t_2 == (long)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 83; __pyx_clineno = __LINE__; goto __pyx_L5;}
+    __pyx_t_2 = __Pyx_PyInt_AsLong(__pyx_cur_scope->__pyx_v_size); if (unlikely((__pyx_t_2 == (long)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 88; __pyx_clineno = __LINE__; goto __pyx_L5;}
     for (__pyx_t_1 = 0; __pyx_t_1 < __pyx_t_2; __pyx_t_1+=1) {
       __pyx_cur_scope->__pyx_v_k = __pyx_t_1;
 
-      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":84
+      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":89
  *         try:
  *             for k in range(size):
  *                 derivation = derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)             # <<<<<<<<<<<<<<
@@ -9806,7 +9883,7 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_18generator6(__pyx_GeneratorObject
  */
       __pyx_cur_scope->__pyx_v_derivation = __pyx_cur_scope->__pyx_v_derivations->LazyKthBest((__pyx_cur_scope->__pyx_v_self->hg->nodes_.size() - 1), __pyx_cur_scope->__pyx_v_k);
 
-      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":85
+      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":90
  *             for k in range(size):
  *                 derivation = derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
  *                 if not derivation: break             # <<<<<<<<<<<<<<
@@ -9820,23 +9897,23 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_18generator6(__pyx_GeneratorObject
       }
       __pyx_L9:;
 
-      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":86
+      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":91
  *                 derivation = derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
  *                 if not derivation: break
  *                 fmap = SparseVector.__new__(SparseVector)             # <<<<<<<<<<<<<<
  *                 fmap.vector = new FastSparseVector[weight_t](derivation._yield)
  *                 yield fmap
  */
-      __pyx_t_4 = __Pyx_tp_new(((PyObject*)__pyx_ptype_5_cdec_SparseVector)); if (unlikely(!__pyx_t_4)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 86; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      __pyx_t_4 = __Pyx_tp_new(((PyObject*)__pyx_ptype_5_cdec_SparseVector)); if (unlikely(!__pyx_t_4)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 91; __pyx_clineno = __LINE__; goto __pyx_L5;}
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-      if (!(likely(__Pyx_TypeTest(__pyx_t_4, __pyx_ptype_5_cdec_SparseVector)))) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 86; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      if (!(likely(__Pyx_TypeTest(__pyx_t_4, __pyx_ptype_5_cdec_SparseVector)))) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 91; __pyx_clineno = __LINE__; goto __pyx_L5;}
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       __Pyx_XDECREF(((PyObject *)__pyx_cur_scope->__pyx_v_fmap));
       __Pyx_GIVEREF(__pyx_t_4);
       __pyx_cur_scope->__pyx_v_fmap = ((struct __pyx_obj_5_cdec_SparseVector *)__pyx_t_4);
       __pyx_t_4 = 0;
 
-      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":87
+      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":92
  *                 if not derivation: break
  *                 fmap = SparseVector.__new__(SparseVector)
  *                 fmap.vector = new FastSparseVector[weight_t](derivation._yield)             # <<<<<<<<<<<<<<
@@ -9845,7 +9922,7 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_18generator6(__pyx_GeneratorObject
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       __pyx_cur_scope->__pyx_v_fmap->vector = new FastSparseVector<weight_t>(__pyx_cur_scope->__pyx_v_derivation->yield);
 
-      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":88
+      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":93
  *                 fmap = SparseVector.__new__(SparseVector)
  *                 fmap.vector = new FastSparseVector[weight_t](derivation._yield)
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-      if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 88; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 93; __pyx_clineno = __LINE__; goto __pyx_L5;}
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     __pyx_L8_break:;
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":90
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":95
  *                 yield fmap
  *         finally:
  *             del derivations             # <<<<<<<<<<<<<<
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+static PyObject *__pyx_gb_5_cdec_10Hypergraph_23generator7(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value); /* proto */
 
 /* Python wrapper */
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-static PyObject *__pyx_pw_5_cdec_10Hypergraph_20sample(PyObject *__pyx_v_self, PyObject *__pyx_arg_n) {
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_22sample(PyObject *__pyx_v_self, PyObject *__pyx_arg_n); /*proto*/
+static char __pyx_doc_5_cdec_10Hypergraph_21sample[] = "hg.sample(n) -> Sample of n hypotheses from the hypergraph.";
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_22sample(PyObject *__pyx_v_self, PyObject *__pyx_arg_n) {
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+    __pyx_v_n = __Pyx_PyInt_AsUnsignedInt(__pyx_arg_n); if (unlikely((__pyx_v_n == (unsigned int)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 97; __pyx_clineno = __LINE__; goto __pyx_L3_error;}
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+  __pyx_r = __pyx_pf_5_cdec_10Hypergraph_21sample(((struct __pyx_obj_5_cdec_Hypergraph *)__pyx_v_self), ((unsigned int)__pyx_v_n));
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-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":92
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  */
 
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_19sample(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, unsigned int __pyx_v_n) {
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_21sample(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, unsigned int __pyx_v_n) {
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+    __pyx_GeneratorObject *gen = __Pyx_Generator_New((__pyx_generator_body_t) __pyx_gb_5_cdec_10Hypergraph_23generator7, (PyObject *) __pyx_cur_scope); if (unlikely(!gen)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 97; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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 }
 
-static PyObject *__pyx_gb_5_cdec_10Hypergraph_21generator7(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value) /* generator body */
+static PyObject *__pyx_gb_5_cdec_10Hypergraph_23generator7(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value) /* generator body */
 {
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-  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 92; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 97; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":94
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":99
  *     def sample(self, unsigned n):
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-  try {__pyx_t_1 = new std::vector<HypergraphSampler::Hypothesis>();} catch(...) {__Pyx_CppExn2PyErr(); {__pyx_filename = __pyx_f[3]; __pyx_lineno = 94; __pyx_clineno = __LINE__; goto __pyx_L1_error;}}
+  try {__pyx_t_1 = new std::vector<HypergraphSampler::Hypothesis>();} catch(...) {__Pyx_CppExn2PyErr(); {__pyx_filename = __pyx_f[3]; __pyx_lineno = 99; __pyx_clineno = __LINE__; goto __pyx_L1_error;}}
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":95
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":100
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":97
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":102
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   /*try:*/ {
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":98
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":103
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-      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":99
+      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":104
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+      __pyx_t_4 = PyBytes_FromString(TD::GetString(((__pyx_cur_scope->__pyx_v_hypos[0])[__pyx_cur_scope->__pyx_v_k]).words).c_str()); if (unlikely(!__pyx_t_4)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 104; __pyx_clineno = __LINE__; goto __pyx_L5;}
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-      __pyx_t_5 = PyTuple_New(2); if (unlikely(!__pyx_t_5)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 99; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      __pyx_t_5 = PyTuple_New(2); if (unlikely(!__pyx_t_5)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 104; __pyx_clineno = __LINE__; goto __pyx_L5;}
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@@ -10060,7 +10137,7 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_21generator7(__pyx_GeneratorObject
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       __Pyx_GIVEREF(((PyObject *)__pyx_n_s__utf8));
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+      __pyx_t_4 = PyObject_Call(((PyObject *)((PyObject*)(&PyUnicode_Type))), ((PyObject *)__pyx_t_5), NULL); if (unlikely(!__pyx_t_4)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 104; __pyx_clineno = __LINE__; goto __pyx_L5;}
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       __pyx_t_3 = __pyx_cur_scope->__pyx_t_1;
-      if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 99; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 104; __pyx_clineno = __LINE__; goto __pyx_L5;}
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":101
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":106
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+static PyObject *__pyx_gb_5_cdec_10Hypergraph_26generator8(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value); /* proto */
 
 /* Python wrapper */
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-static PyObject *__pyx_pw_5_cdec_10Hypergraph_23sample_trees(PyObject *__pyx_v_self, PyObject *__pyx_arg_n) {
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_25sample_trees(PyObject *__pyx_v_self, PyObject *__pyx_arg_n); /*proto*/
+static char __pyx_doc_5_cdec_10Hypergraph_24sample_trees[] = "hg.sample_trees(n) -> Sample of n trees from the hypergraph.";
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_25sample_trees(PyObject *__pyx_v_self, PyObject *__pyx_arg_n) {
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+  __pyx_r = __pyx_pf_5_cdec_10Hypergraph_24sample_trees(((struct __pyx_obj_5_cdec_Hypergraph *)__pyx_v_self), ((unsigned int)__pyx_v_n));
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-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":103
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-static PyObject *__pyx_pf_5_cdec_10Hypergraph_22sample_trees(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, unsigned int __pyx_v_n) {
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_24sample_trees(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, unsigned int __pyx_v_n) {
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+    __pyx_GeneratorObject *gen = __Pyx_Generator_New((__pyx_generator_body_t) __pyx_gb_5_cdec_10Hypergraph_26generator8, (PyObject *) __pyx_cur_scope); if (unlikely(!gen)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 108; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-static PyObject *__pyx_gb_5_cdec_10Hypergraph_24generator8(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value) /* generator body */
+static PyObject *__pyx_gb_5_cdec_10Hypergraph_26generator8(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value) /* generator body */
 {
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-  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 103; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 108; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":105
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  *        hypergraph.sample_trees(self.hg[0], n, self._rng(), trees)
  *        cdef unsigned k
  */
-  try {__pyx_t_1 = new std::vector<std::string>();} catch(...) {__Pyx_CppExn2PyErr(); {__pyx_filename = __pyx_f[3]; __pyx_lineno = 105; __pyx_clineno = __LINE__; goto __pyx_L1_error;}}
+  try {__pyx_t_1 = new std::vector<std::string>();} catch(...) {__Pyx_CppExn2PyErr(); {__pyx_filename = __pyx_f[3]; __pyx_lineno = 110; __pyx_clineno = __LINE__; goto __pyx_L1_error;}}
   __pyx_cur_scope->__pyx_v_trees = __pyx_t_1;
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":106
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":111
  *        """hg.sample_trees(n) -> Sample of n trees from the hypergraph."""
  *        cdef vector[string]* trees = new vector[string]()
  *        hypergraph.sample_trees(self.hg[0], n, self._rng(), trees)             # <<<<<<<<<<<<<<
@@ -10235,7 +10312,7 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_24generator8(__pyx_GeneratorObject
  */
   HypergraphSampler::sample_trees((__pyx_cur_scope->__pyx_v_self->hg[0]), __pyx_cur_scope->__pyx_v_n, ((struct __pyx_vtabstruct_5_cdec_Hypergraph *)__pyx_cur_scope->__pyx_v_self->__pyx_vtab)->_rng(__pyx_cur_scope->__pyx_v_self), __pyx_cur_scope->__pyx_v_trees);
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":108
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":113
  *        hypergraph.sample_trees(self.hg[0], n, self._rng(), trees)
  *        cdef unsigned k
  *        try:             # <<<<<<<<<<<<<<
@@ -10244,7 +10321,7 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_24generator8(__pyx_GeneratorObject
  */
   /*try:*/ {
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":109
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":114
  *        cdef unsigned k
  *        try:
  *            for k in range(trees.size()):             # <<<<<<<<<<<<<<
@@ -10255,16 +10332,16 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_24generator8(__pyx_GeneratorObject
     for (__pyx_t_3 = 0; __pyx_t_3 < __pyx_t_2; __pyx_t_3+=1) {
       __pyx_cur_scope->__pyx_v_k = __pyx_t_3;
 
-      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":110
+      /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":115
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  *            for k in range(trees.size()):
  *                yield unicode(trees[0][k].c_str(), 'utf8')             # <<<<<<<<<<<<<<
  *        finally:
  *            del trees
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-      __pyx_t_4 = PyBytes_FromString(((__pyx_cur_scope->__pyx_v_trees[0])[__pyx_cur_scope->__pyx_v_k]).c_str()); if (unlikely(!__pyx_t_4)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 110; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      __pyx_t_4 = PyBytes_FromString(((__pyx_cur_scope->__pyx_v_trees[0])[__pyx_cur_scope->__pyx_v_k]).c_str()); if (unlikely(!__pyx_t_4)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 115; __pyx_clineno = __LINE__; goto __pyx_L5;}
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-      __pyx_t_5 = PyTuple_New(2); if (unlikely(!__pyx_t_5)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 110; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      __pyx_t_5 = PyTuple_New(2); if (unlikely(!__pyx_t_5)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 115; __pyx_clineno = __LINE__; goto __pyx_L5;}
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       PyTuple_SET_ITEM(__pyx_t_5, 0, ((PyObject *)__pyx_t_4));
       __Pyx_GIVEREF(((PyObject *)__pyx_t_4));
@@ -10272,7 +10349,7 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_24generator8(__pyx_GeneratorObject
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       __Pyx_GIVEREF(((PyObject *)__pyx_n_s__utf8));
       __pyx_t_4 = 0;
-      __pyx_t_4 = PyObject_Call(((PyObject *)((PyObject*)(&PyUnicode_Type))), ((PyObject *)__pyx_t_5), NULL); if (unlikely(!__pyx_t_4)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 110; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      __pyx_t_4 = PyObject_Call(((PyObject *)((PyObject*)(&PyUnicode_Type))), ((PyObject *)__pyx_t_5), NULL); if (unlikely(!__pyx_t_4)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 115; __pyx_clineno = __LINE__; goto __pyx_L5;}
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@@ -10287,11 +10364,11 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_24generator8(__pyx_GeneratorObject
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       __pyx_t_3 = __pyx_cur_scope->__pyx_t_1;
-      if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 110; __pyx_clineno = __LINE__; goto __pyx_L5;}
+      if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 115; __pyx_clineno = __LINE__; goto __pyx_L5;}
     }
   }
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":112
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":117
  *                yield unicode(trees[0][k].c_str(), 'utf8')
  *        finally:
  *            del trees             # <<<<<<<<<<<<<<
@@ -10340,18 +10417,18 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_24generator8(__pyx_GeneratorObject
 }
 
 /* Python wrapper */
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-static char __pyx_doc_5_cdec_10Hypergraph_25intersect[] = "hg.intersect(Lattice/string): Intersect the hypergraph with the provided reference.";
-static PyObject *__pyx_pw_5_cdec_10Hypergraph_26intersect(PyObject *__pyx_v_self, PyObject *__pyx_v_inp) {
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_28intersect(PyObject *__pyx_v_self, PyObject *__pyx_v_inp); /*proto*/
+static char __pyx_doc_5_cdec_10Hypergraph_27intersect[] = "hg.intersect(Lattice/string): Intersect the hypergraph with the provided reference.";
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_28intersect(PyObject *__pyx_v_self, PyObject *__pyx_v_inp) {
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+  __pyx_r = __pyx_pf_5_cdec_10Hypergraph_27intersect(((struct __pyx_obj_5_cdec_Hypergraph *)__pyx_v_self), ((PyObject *)__pyx_v_inp));
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-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":114
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":119
  *            del trees
  * 
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@@ -10359,7 +10436,7 @@ static PyObject *__pyx_pw_5_cdec_10Hypergraph_26intersect(PyObject *__pyx_v_self
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-static PyObject *__pyx_pf_5_cdec_10Hypergraph_25intersect(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_inp) {
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_27intersect(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_inp) {
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@@ -10371,7 +10448,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_25intersect(struct __pyx_obj_5_cde
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":117
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":122
  *         """hg.intersect(Lattice/string): Intersect the hypergraph with the provided reference."""
  *         cdef Lattice lat
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   if (__pyx_t_2) {
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":118
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":123
  *         cdef Lattice lat
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@@ -10396,7 +10473,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_25intersect(struct __pyx_obj_5_cde
     goto __pyx_L3;
   }
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":119
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":124
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@@ -10405,23 +10482,23 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_25intersect(struct __pyx_obj_5_cde
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+  __pyx_t_2 = PyObject_IsInstance(__pyx_v_inp, __pyx_t_1); if (unlikely(__pyx_t_2 == -1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 124; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":120
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":125
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-    __pyx_t_1 = PyTuple_New(1); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 120; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    __pyx_t_1 = PyTuple_New(1); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 125; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-    __pyx_t_3 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_Lattice)), ((PyObject *)__pyx_t_1), NULL); if (unlikely(!__pyx_t_3)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 120; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    __pyx_t_3 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_Lattice)), ((PyObject *)__pyx_t_1), NULL); if (unlikely(!__pyx_t_3)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 125; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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@@ -10430,30 +10507,30 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_25intersect(struct __pyx_obj_5_cde
   }
   /*else*/ {
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":122
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":127
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+    __pyx_t_3 = PyNumber_Remainder(((PyObject *)__pyx_kp_s_15), ((PyObject *)Py_TYPE(__pyx_v_inp))); if (unlikely(!__pyx_t_3)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 127; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-    __pyx_t_1 = PyTuple_New(1); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 122; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    __pyx_t_1 = PyTuple_New(1); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 127; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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+    __pyx_t_3 = PyObject_Call(__pyx_builtin_TypeError, ((PyObject *)__pyx_t_1), NULL); if (unlikely(!__pyx_t_3)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 127; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-    {__pyx_filename = __pyx_f[3]; __pyx_lineno = 122; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    {__pyx_filename = __pyx_f[3]; __pyx_lineno = 127; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":123
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":128
  *         else:
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@@ -10461,7 +10538,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_25intersect(struct __pyx_obj_5_cde
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+  __pyx_t_3 = __Pyx_PyBool_FromLong(HG::Intersect((__pyx_v_lat->lattice[0]), __pyx_v_self->hg)); if (unlikely(!__pyx_t_3)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 128; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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@@ -10482,9 +10559,9 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_25intersect(struct __pyx_obj_5_cde
 }
 
 /* Python wrapper */
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-static PyObject *__pyx_pw_5_cdec_10Hypergraph_28prune(PyObject *__pyx_v_self, PyObject *__pyx_args, PyObject *__pyx_kwds) {
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_30prune(PyObject *__pyx_v_self, PyObject *__pyx_args, PyObject *__pyx_kwds); /*proto*/
+static char __pyx_doc_5_cdec_10Hypergraph_29prune[] = "hg.prune(beam_alpha=0, density=0): Prune the hypergraph.\n        beam_alpha: use beam pruning\n        density: use density pruning";
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_30prune(PyObject *__pyx_v_self, PyObject *__pyx_args, PyObject *__pyx_kwds) {
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@@ -10521,7 +10598,7 @@ static PyObject *__pyx_pw_5_cdec_10Hypergraph_28prune(PyObject *__pyx_v_self, Py
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+  __Pyx_RaiseArgtupleInvalid("prune", 0, 0, 2, PyTuple_GET_SIZE(__pyx_args)); {__pyx_filename = __pyx_f[3]; __pyx_lineno = 130; __pyx_clineno = __LINE__; goto __pyx_L3_error;}
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+  __pyx_r = __pyx_pf_5_cdec_10Hypergraph_29prune(((struct __pyx_obj_5_cdec_Hypergraph *)__pyx_v_self), __pyx_v_beam_alpha, __pyx_v_density, __pyx_v_kwargs);
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 }
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":125
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":130
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-static PyObject *__pyx_pf_5_cdec_10Hypergraph_27prune(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_beam_alpha, PyObject *__pyx_v_density, PyObject *__pyx_v_kwargs) {
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_29prune(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self, PyObject *__pyx_v_beam_alpha, PyObject *__pyx_v_density, PyObject *__pyx_v_kwargs) {
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":129
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":134
  *         beam_alpha: use beam pruning
  *         density: use density pruning"""
  *         cdef hypergraph.EdgeMask* preserve_mask = NULL             # <<<<<<<<<<<<<<
@@ -10578,17 +10655,17 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_27prune(struct __pyx_obj_5_cdec_Hy
  */
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":130
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":135
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+  __pyx_t_1 = (__Pyx_PyDict_Contains(((PyObject *)__pyx_n_s_16), ((PyObject *)__pyx_v_kwargs), Py_EQ)); if (unlikely(__pyx_t_1 < 0)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 135; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":131
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":136
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@@ -10597,7 +10674,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_27prune(struct __pyx_obj_5_cdec_Hy
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-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":132
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":137
  *         if 'csplit_preserve_full_word' in kwargs:
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  *              preserve_mask[0][hypergraph.GetFullWordEdgeIndex(self.hg[0])] = True             # <<<<<<<<<<<<<<
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":133
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":138
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":134
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":139
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-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":135
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":140
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-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":137
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-static PyObject *__pyx_pf_5_cdec_10Hypergraph_29lattice(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self) {
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+  __pyx_t_1 = PyBytes_FromString(HypergraphIO::AsPLF((__pyx_v_self->hg[0]), 1).c_str()); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 144; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":140
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":145
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-static PyObject *__pyx_pf_5_cdec_10Hypergraph_31plf(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self) {
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@@ -10852,7 +10929,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_33reweight(struct __pyx_obj_5_cdec
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":148
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":153
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-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":149
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":154
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@@ -10876,7 +10953,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_33reweight(struct __pyx_obj_5_cdec
     goto __pyx_L3;
   }
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":150
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":155
  *         if isinstance(weights, SparseVector):
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  *         elif isinstance(weights, DenseVector):             # <<<<<<<<<<<<<<
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-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":151
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":156
  *             self.hg.Reweight((<SparseVector> weights).vector[0])
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  *             self.hg.Reweight((<DenseVector> weights).vector[0])             # <<<<<<<<<<<<<<
@@ -10901,26 +10978,26 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_33reweight(struct __pyx_obj_5_cdec
   }
   /*else*/ {
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":153
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":158
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+    __pyx_t_1 = PyNumber_Remainder(((PyObject *)__pyx_kp_s_17), ((PyObject *)Py_TYPE(__pyx_v_weights))); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 158; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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+    __pyx_t_3 = PyTuple_New(1); if (unlikely(!__pyx_t_3)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 158; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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+    __pyx_t_1 = PyObject_Call(__pyx_builtin_TypeError, ((PyObject *)__pyx_t_3), NULL); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 158; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-    {__pyx_filename = __pyx_f[3]; __pyx_lineno = 153; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    {__pyx_filename = __pyx_f[3]; __pyx_lineno = 158; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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@@ -10949,7 +11026,7 @@ static PyObject *__pyx_pw_5_cdec_10Hypergraph_5edges_1__get__(PyObject *__pyx_v_
   return __pyx_r;
 }
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":156
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":161
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  *     property edges:
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@@ -10975,7 +11052,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_5edges___get__(struct __pyx_obj_5_
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   __Pyx_GIVEREF((PyObject *)__pyx_cur_scope->__pyx_v_self);
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+    __pyx_GeneratorObject *gen = __Pyx_Generator_New((__pyx_generator_body_t) __pyx_gb_5_cdec_10Hypergraph_5edges_2generator9, (PyObject *) __pyx_cur_scope); if (unlikely(!gen)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 161; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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@@ -11011,9 +11088,9 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_5edges_2generator9(__pyx_Generator
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   }
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-  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 156; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 161; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":158
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":163
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@@ -11024,16 +11101,16 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_5edges_2generator9(__pyx_Generator
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     __pyx_cur_scope->__pyx_v_i = __pyx_t_2;
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":159
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":164
  *             cdef unsigned i
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  *     property nodes:
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-    __pyx_t_3 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_HypergraphEdge)), ((PyObject *)__pyx_empty_tuple), NULL); if (unlikely(!__pyx_t_3)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 159; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    __pyx_t_3 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_HypergraphEdge)), ((PyObject *)__pyx_empty_tuple), NULL); if (unlikely(!__pyx_t_3)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 164; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-    __pyx_t_4 = ((struct __pyx_vtabstruct_5_cdec_HypergraphEdge *)((struct __pyx_obj_5_cdec_HypergraphEdge *)__pyx_t_3)->__pyx_vtab)->init(((struct __pyx_obj_5_cdec_HypergraphEdge *)__pyx_t_3), __pyx_cur_scope->__pyx_v_self->hg, __pyx_cur_scope->__pyx_v_i); if (unlikely(!__pyx_t_4)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 159; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    __pyx_t_4 = ((struct __pyx_vtabstruct_5_cdec_HypergraphEdge *)((struct __pyx_obj_5_cdec_HypergraphEdge *)__pyx_t_3)->__pyx_vtab)->init(((struct __pyx_obj_5_cdec_HypergraphEdge *)__pyx_t_3), __pyx_cur_scope->__pyx_v_self->hg, __pyx_cur_scope->__pyx_v_i); if (unlikely(!__pyx_t_4)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 164; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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@@ -11048,7 +11125,7 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_5edges_2generator9(__pyx_Generator
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     __pyx_t_2 = __pyx_cur_scope->__pyx_t_1;
-    if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 159; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 164; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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@@ -11076,7 +11153,7 @@ static PyObject *__pyx_pw_5_cdec_10Hypergraph_5nodes_1__get__(PyObject *__pyx_v_
   return __pyx_r;
 }
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":162
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":167
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  *     property nodes:
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+    __pyx_GeneratorObject *gen = __Pyx_Generator_New((__pyx_generator_body_t) __pyx_gb_5_cdec_10Hypergraph_5nodes_2generator10, (PyObject *) __pyx_cur_scope); if (unlikely(!gen)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 167; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 162; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 167; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":164
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":169
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     __pyx_cur_scope->__pyx_v_i = __pyx_t_2;
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":165
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":170
  *             cdef unsigned i
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  *     property goal:
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-    __pyx_t_3 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_HypergraphNode)), ((PyObject *)__pyx_empty_tuple), NULL); if (unlikely(!__pyx_t_3)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 165; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    __pyx_t_3 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_HypergraphNode)), ((PyObject *)__pyx_empty_tuple), NULL); if (unlikely(!__pyx_t_3)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 170; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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+    __pyx_t_4 = ((struct __pyx_vtabstruct_5_cdec_HypergraphNode *)((struct __pyx_obj_5_cdec_HypergraphNode *)__pyx_t_3)->__pyx_vtab)->init(((struct __pyx_obj_5_cdec_HypergraphNode *)__pyx_t_3), __pyx_cur_scope->__pyx_v_self->hg, __pyx_cur_scope->__pyx_v_i); if (unlikely(!__pyx_t_4)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 170; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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@@ -11175,7 +11252,7 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_5nodes_2generator10(__pyx_Generato
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     __pyx_t_2 = __pyx_cur_scope->__pyx_t_1;
-    if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 165; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 170; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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@@ -11202,7 +11279,7 @@ static PyObject *__pyx_pw_5_cdec_10Hypergraph_4goal_1__get__(PyObject *__pyx_v_s
   return __pyx_r;
 }
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":168
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":173
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  *     property goal:
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":169
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":174
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+  __pyx_t_1 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_HypergraphNode)), ((PyObject *)__pyx_empty_tuple), NULL); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 174; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-  __pyx_t_2 = ((struct __pyx_vtabstruct_5_cdec_HypergraphNode *)((struct __pyx_obj_5_cdec_HypergraphNode *)__pyx_t_1)->__pyx_vtab)->init(((struct __pyx_obj_5_cdec_HypergraphNode *)__pyx_t_1), __pyx_v_self->hg, __pyx_v_self->hg->GoalNode()); if (unlikely(!__pyx_t_2)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 169; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_t_2 = ((struct __pyx_vtabstruct_5_cdec_HypergraphNode *)((struct __pyx_obj_5_cdec_HypergraphNode *)__pyx_t_1)->__pyx_vtab)->init(((struct __pyx_obj_5_cdec_HypergraphNode *)__pyx_t_1), __pyx_v_self->hg, __pyx_v_self->hg->GoalNode()); if (unlikely(!__pyx_t_2)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 174; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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@@ -11261,7 +11338,7 @@ static PyObject *__pyx_pw_5_cdec_10Hypergraph_6npaths_1__get__(PyObject *__pyx_v
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 }
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":172
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":177
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":173
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":178
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+  __pyx_t_1 = PyFloat_FromDouble(__pyx_v_self->hg->NumberOfPaths()); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 178; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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@@ -11305,18 +11382,18 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_6npaths___get__(struct __pyx_obj_5
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 /* Python wrapper */
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-static PyObject *__pyx_pw_5_cdec_10Hypergraph_36inside_outside(PyObject *__pyx_v_self, CYTHON_UNUSED PyObject *unused) {
+static PyObject *__pyx_pw_5_cdec_10Hypergraph_38inside_outside(PyObject *__pyx_v_self, CYTHON_UNUSED PyObject *unused); /*proto*/
+static char __pyx_doc_5_cdec_10Hypergraph_37inside_outside[] = "hg.inside_outside() -> SparseVector with inside-outside scores for each feature.";
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   __Pyx_RefNannySetupContext("inside_outside (wrapper)", 0);
-  __pyx_r = __pyx_pf_5_cdec_10Hypergraph_35inside_outside(((struct __pyx_obj_5_cdec_Hypergraph *)__pyx_v_self));
+  __pyx_r = __pyx_pf_5_cdec_10Hypergraph_37inside_outside(((struct __pyx_obj_5_cdec_Hypergraph *)__pyx_v_self));
   __Pyx_RefNannyFinishContext();
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 }
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":175
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":180
  *             return self.hg.NumberOfPaths()
  * 
  *     def inside_outside(self):             # <<<<<<<<<<<<<<
@@ -11324,7 +11401,7 @@ static PyObject *__pyx_pw_5_cdec_10Hypergraph_36inside_outside(PyObject *__pyx_v
  *         cdef FastSparseVector[prob_t]* result = new FastSparseVector[prob_t]()
  */
 
-static PyObject *__pyx_pf_5_cdec_10Hypergraph_35inside_outside(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self) {
+static PyObject *__pyx_pf_5_cdec_10Hypergraph_37inside_outside(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self) {
   FastSparseVector<prob_t> *__pyx_v_result;
   prob_t __pyx_v_z;
   struct __pyx_obj_5_cdec_SparseVector *__pyx_v_vector = 0;
@@ -11340,7 +11417,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_35inside_outside(struct __pyx_obj_
   int __pyx_clineno = 0;
   __Pyx_RefNannySetupContext("inside_outside", 0);
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":177
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":182
  *     def inside_outside(self):
  *         """hg.inside_outside() -> SparseVector with inside-outside scores for each feature."""
  *         cdef FastSparseVector[prob_t]* result = new FastSparseVector[prob_t]()             # <<<<<<<<<<<<<<
@@ -11349,7 +11426,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_35inside_outside(struct __pyx_obj_
  */
   __pyx_v_result = new FastSparseVector<prob_t>();
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":178
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":183
  *         """hg.inside_outside() -> SparseVector with inside-outside scores for each feature."""
  *         cdef FastSparseVector[prob_t]* result = new FastSparseVector[prob_t]()
  *         cdef prob_t z = hypergraph.InsideOutside(self.hg[0], result)             # <<<<<<<<<<<<<<
@@ -11358,7 +11435,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_35inside_outside(struct __pyx_obj_
  */
   __pyx_v_z = InsideOutside<prob_t, EdgeProb, SparseVector<prob_t>, EdgeFeaturesAndProbWeightFunction>((__pyx_v_self->hg[0]), __pyx_v_result);
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":179
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":184
  *         cdef FastSparseVector[prob_t]* result = new FastSparseVector[prob_t]()
  *         cdef prob_t z = hypergraph.InsideOutside(self.hg[0], result)
  *         result[0] /= z             # <<<<<<<<<<<<<<
@@ -11367,20 +11444,20 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_35inside_outside(struct __pyx_obj_
  */
   (__pyx_v_result[0]) /= __pyx_v_z;
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":180
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":185
  *         cdef prob_t z = hypergraph.InsideOutside(self.hg[0], result)
  *         result[0] /= z
  *         cdef SparseVector vector = SparseVector.__new__(SparseVector)             # <<<<<<<<<<<<<<
  *         vector.vector = new FastSparseVector[double]()
  *         cdef FastSparseVector[prob_t].const_iterator* it = new FastSparseVector[prob_t].const_iterator(result[0], False)
  */
-  __pyx_t_1 = __Pyx_tp_new(((PyObject*)__pyx_ptype_5_cdec_SparseVector)); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 180; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_t_1 = __Pyx_tp_new(((PyObject*)__pyx_ptype_5_cdec_SparseVector)); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 185; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_GOTREF(__pyx_t_1);
-  if (!(likely(__Pyx_TypeTest(__pyx_t_1, __pyx_ptype_5_cdec_SparseVector)))) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 180; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (!(likely(__Pyx_TypeTest(__pyx_t_1, __pyx_ptype_5_cdec_SparseVector)))) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 185; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_v_vector = ((struct __pyx_obj_5_cdec_SparseVector *)__pyx_t_1);
   __pyx_t_1 = 0;
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":181
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":186
  *         result[0] /= z
  *         cdef SparseVector vector = SparseVector.__new__(SparseVector)
  *         vector.vector = new FastSparseVector[double]()             # <<<<<<<<<<<<<<
@@ -11389,7 +11466,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_35inside_outside(struct __pyx_obj_
  */
   __pyx_v_vector->vector = new FastSparseVector<double>();
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":182
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":187
  *         cdef SparseVector vector = SparseVector.__new__(SparseVector)
  *         vector.vector = new FastSparseVector[double]()
  *         cdef FastSparseVector[prob_t].const_iterator* it = new FastSparseVector[prob_t].const_iterator(result[0], False)             # <<<<<<<<<<<<<<
@@ -11398,7 +11475,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_35inside_outside(struct __pyx_obj_
  */
   __pyx_v_it = new FastSparseVector<prob_t>::const_iterator((__pyx_v_result[0]), 0);
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":184
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":189
  *         cdef FastSparseVector[prob_t].const_iterator* it = new FastSparseVector[prob_t].const_iterator(result[0], False)
  *         cdef unsigned i
  *         for i in range(result.size()):             # <<<<<<<<<<<<<<
@@ -11409,7 +11486,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_35inside_outside(struct __pyx_obj_
   for (__pyx_t_3 = 0; __pyx_t_3 < __pyx_t_2; __pyx_t_3+=1) {
     __pyx_v_i = __pyx_t_3;
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":185
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":190
  *         cdef unsigned i
  *         for i in range(result.size()):
  *             vector.vector.set_value(it[0].ptr().first, log(it[0].ptr().second))             # <<<<<<<<<<<<<<
@@ -11418,7 +11495,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_35inside_outside(struct __pyx_obj_
  */
     __pyx_v_vector->vector->set_value((__pyx_v_it[0]).operator->()->first, log((__pyx_v_it[0]).operator->()->second));
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":186
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":191
  *         for i in range(result.size()):
  *             vector.vector.set_value(it[0].ptr().first, log(it[0].ptr().second))
  *             pinc(it[0]) # ++it             # <<<<<<<<<<<<<<
@@ -11428,7 +11505,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_35inside_outside(struct __pyx_obj_
     (++(__pyx_v_it[0]));
   }
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":187
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":192
  *             vector.vector.set_value(it[0].ptr().first, log(it[0].ptr().second))
  *             pinc(it[0]) # ++it
  *         del it             # <<<<<<<<<<<<<<
@@ -11437,7 +11514,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_35inside_outside(struct __pyx_obj_
  */
   delete __pyx_v_it;
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":188
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":193
  *             pinc(it[0]) # ++it
  *         del it
  *         del result             # <<<<<<<<<<<<<<
@@ -11446,7 +11523,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_35inside_outside(struct __pyx_obj_
  */
   delete __pyx_v_result;
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":189
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":194
  *         del it
  *         del result
  *         return vector             # <<<<<<<<<<<<<<
@@ -11471,7 +11548,7 @@ static PyObject *__pyx_pf_5_cdec_10Hypergraph_35inside_outside(struct __pyx_obj_
   return __pyx_r;
 }
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":196
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":201
  *     cdef public TRule trule
  * 
  *     cdef init(self, hypergraph.Hypergraph* hg, unsigned i):             # <<<<<<<<<<<<<<
@@ -11488,7 +11565,7 @@ static PyObject *__pyx_f_5_cdec_14HypergraphEdge_init(struct __pyx_obj_5_cdec_Hy
   int __pyx_clineno = 0;
   __Pyx_RefNannySetupContext("init", 0);
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":197
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":202
  * 
  *     cdef init(self, hypergraph.Hypergraph* hg, unsigned i):
  *         self.hg = hg             # <<<<<<<<<<<<<<
@@ -11497,7 +11574,7 @@ static PyObject *__pyx_f_5_cdec_14HypergraphEdge_init(struct __pyx_obj_5_cdec_Hy
  */
   __pyx_v_self->hg = __pyx_v_hg;
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":198
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":203
  *     cdef init(self, hypergraph.Hypergraph* hg, unsigned i):
  *         self.hg = hg
  *         self.edge = &hg.edges_[i]             # <<<<<<<<<<<<<<
@@ -11506,23 +11583,23 @@ static PyObject *__pyx_f_5_cdec_14HypergraphEdge_init(struct __pyx_obj_5_cdec_Hy
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   __pyx_v_self->edge = (&(__pyx_v_hg->edges_[__pyx_v_i]));
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":199
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":204
  *         self.hg = hg
  *         self.edge = &hg.edges_[i]
  *         self.trule = TRule.__new__(TRule)             # <<<<<<<<<<<<<<
  *         self.trule.rule = new shared_ptr[grammar.TRule](self.edge.rule_)
  *         return self
  */
-  __pyx_t_1 = __Pyx_tp_new(((PyObject*)__pyx_ptype_5_cdec_TRule)); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 199; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_t_1 = __Pyx_tp_new(((PyObject*)__pyx_ptype_5_cdec_TRule)); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 204; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_GOTREF(__pyx_t_1);
-  if (!(likely(__Pyx_TypeTest(__pyx_t_1, __pyx_ptype_5_cdec_TRule)))) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 199; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (!(likely(__Pyx_TypeTest(__pyx_t_1, __pyx_ptype_5_cdec_TRule)))) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 204; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_GIVEREF(__pyx_t_1);
   __Pyx_GOTREF(__pyx_v_self->trule);
   __Pyx_DECREF(((PyObject *)__pyx_v_self->trule));
   __pyx_v_self->trule = ((struct __pyx_obj_5_cdec_TRule *)__pyx_t_1);
   __pyx_t_1 = 0;
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":200
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":205
  *         self.edge = &hg.edges_[i]
  *         self.trule = TRule.__new__(TRule)
  *         self.trule.rule = new shared_ptr[grammar.TRule](self.edge.rule_)             # <<<<<<<<<<<<<<
@@ -11531,7 +11608,7 @@ static PyObject *__pyx_f_5_cdec_14HypergraphEdge_init(struct __pyx_obj_5_cdec_Hy
  */
   __pyx_v_self->trule->rule = new boost::shared_ptr<TRule>(__pyx_v_self->edge->rule_);
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":201
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":206
  *         self.trule = TRule.__new__(TRule)
  *         self.trule.rule = new shared_ptr[grammar.TRule](self.edge.rule_)
  *         return self             # <<<<<<<<<<<<<<
@@ -11566,7 +11643,7 @@ static Py_ssize_t __pyx_pw_5_cdec_14HypergraphEdge_1__len__(PyObject *__pyx_v_se
   return __pyx_r;
 }
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":203
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":208
  *         return self
  * 
  *     def __len__(self):             # <<<<<<<<<<<<<<
@@ -11579,7 +11656,7 @@ static Py_ssize_t __pyx_pf_5_cdec_14HypergraphEdge___len__(struct __pyx_obj_5_cd
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   __Pyx_RefNannySetupContext("__len__", 0);
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":204
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":209
  * 
  *     def __len__(self):
  *         return self.edge.tail_nodes_.size()             # <<<<<<<<<<<<<<
@@ -11606,7 +11683,7 @@ static PyObject *__pyx_pw_5_cdec_14HypergraphEdge_9head_node_1__get__(PyObject *
   return __pyx_r;
 }
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":207
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":212
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  *     property head_node:
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@@ -11624,7 +11701,7 @@ static PyObject *__pyx_pf_5_cdec_14HypergraphEdge_9head_node___get__(struct __py
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":208
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":213
  *     property head_node:
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@@ -11632,9 +11709,9 @@ static PyObject *__pyx_pf_5_cdec_14HypergraphEdge_9head_node___get__(struct __py
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   __Pyx_XDECREF(__pyx_r);
-  __pyx_t_1 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_HypergraphNode)), ((PyObject *)__pyx_empty_tuple), NULL); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 208; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_t_1 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_HypergraphNode)), ((PyObject *)__pyx_empty_tuple), NULL); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 213; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_GOTREF(__pyx_t_1);
-  __pyx_t_2 = ((struct __pyx_vtabstruct_5_cdec_HypergraphNode *)((struct __pyx_obj_5_cdec_HypergraphNode *)__pyx_t_1)->__pyx_vtab)->init(((struct __pyx_obj_5_cdec_HypergraphNode *)__pyx_t_1), __pyx_v_self->hg, __pyx_v_self->edge->head_node_); if (unlikely(!__pyx_t_2)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 208; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_t_2 = ((struct __pyx_vtabstruct_5_cdec_HypergraphNode *)((struct __pyx_obj_5_cdec_HypergraphNode *)__pyx_t_1)->__pyx_vtab)->init(((struct __pyx_obj_5_cdec_HypergraphNode *)__pyx_t_1), __pyx_v_self->hg, __pyx_v_self->edge->head_node_); if (unlikely(!__pyx_t_2)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 213; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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   return __pyx_r;
 }
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":211
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":216
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  *     property tail_nodes:
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@@ -11692,7 +11769,7 @@ static PyObject *__pyx_pf_5_cdec_14HypergraphEdge_10tail_nodes___get__(struct __
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   __Pyx_GIVEREF((PyObject *)__pyx_cur_scope->__pyx_v_self);
   {
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+    __pyx_GeneratorObject *gen = __Pyx_Generator_New((__pyx_generator_body_t) __pyx_gb_5_cdec_14HypergraphEdge_10tail_nodes_2generator11, (PyObject *) __pyx_cur_scope); if (unlikely(!gen)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 216; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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     __Pyx_RefNannyFinishContext();
     return (PyObject *) gen;
@@ -11728,9 +11805,9 @@ static PyObject *__pyx_gb_5_cdec_14HypergraphEdge_10tail_nodes_2generator11(__py
     return NULL;
   }
   __pyx_L3_first_run:;
-  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 211; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 216; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":213
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":218
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     __pyx_cur_scope->__pyx_v_i = __pyx_t_2;
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":214
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":219
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  *     property span:
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-    __pyx_t_3 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_HypergraphNode)), ((PyObject *)__pyx_empty_tuple), NULL); if (unlikely(!__pyx_t_3)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 214; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    __pyx_t_3 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_HypergraphNode)), ((PyObject *)__pyx_empty_tuple), NULL); if (unlikely(!__pyx_t_3)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 219; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
     __Pyx_GOTREF(__pyx_t_3);
-    __pyx_t_4 = ((struct __pyx_vtabstruct_5_cdec_HypergraphNode *)((struct __pyx_obj_5_cdec_HypergraphNode *)__pyx_t_3)->__pyx_vtab)->init(((struct __pyx_obj_5_cdec_HypergraphNode *)__pyx_t_3), __pyx_cur_scope->__pyx_v_self->hg, (__pyx_cur_scope->__pyx_v_self->edge->tail_nodes_[__pyx_cur_scope->__pyx_v_i])); if (unlikely(!__pyx_t_4)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 214; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    __pyx_t_4 = ((struct __pyx_vtabstruct_5_cdec_HypergraphNode *)((struct __pyx_obj_5_cdec_HypergraphNode *)__pyx_t_3)->__pyx_vtab)->init(((struct __pyx_obj_5_cdec_HypergraphNode *)__pyx_t_3), __pyx_cur_scope->__pyx_v_self->hg, (__pyx_cur_scope->__pyx_v_self->edge->tail_nodes_[__pyx_cur_scope->__pyx_v_i])); if (unlikely(!__pyx_t_4)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 219; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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 /* Python wrapper */
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 static PyObject *__pyx_pw_5_cdec_14HypergraphEdge_14feature_values_1__get__(PyObject *__pyx_v_self) {
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+  if (!(likely(((__pyx_v_value) == Py_None) || likely(__Pyx_TypeTest(__pyx_v_value, __pyx_ptype_5_cdec_TRule))))) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 199; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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 }
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":241
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":250
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":242
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":251
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":243
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":252
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":244
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":253
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 }
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":247
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":256
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-  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 247; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":249
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-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":250
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-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":253
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-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":255
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-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":256
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-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":265
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+  if (unlikely(!__Pyx_ArgTypeTest(((PyObject *)__pyx_v_y), __pyx_ptype_5_cdec_HypergraphNode, 1, "y", 0))) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 276; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_r = __pyx_pf_5_cdec_14HypergraphNode___richcmp__(((struct __pyx_obj_5_cdec_HypergraphNode *)__pyx_v_x), ((struct __pyx_obj_5_cdec_HypergraphNode *)__pyx_v_y), ((int)__pyx_v_op));
   goto __pyx_L0;
   __pyx_L1_error:;
@@ -12655,7 +12800,7 @@ static PyObject *__pyx_pw_5_cdec_14HypergraphNode_1__richcmp__(PyObject *__pyx_v
   return __pyx_r;
 }
 
-/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":267
+/* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":276
  *                 return str(TDConvert(-self.node.cat_).c_str())
  * 
  *     def __richcmp__(HypergraphNode x, HypergraphNode y, int op):             # <<<<<<<<<<<<<<
@@ -12673,7 +12818,7 @@ static PyObject *__pyx_pf_5_cdec_14HypergraphNode___richcmp__(struct __pyx_obj_5
   int __pyx_clineno = 0;
   __Pyx_RefNannySetupContext("__richcmp__", 0);
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":270
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":279
  *         if op == 2: # ==
  *             return x.node == y.node
  *         elif op == 3: # !=             # <<<<<<<<<<<<<<
@@ -12682,7 +12827,7 @@ static PyObject *__pyx_pf_5_cdec_14HypergraphNode___richcmp__(struct __pyx_obj_5
  */
   switch (__pyx_v_op) {
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":268
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":277
  * 
  *     def __richcmp__(HypergraphNode x, HypergraphNode y, int op):
  *         if op == 2: # ==             # <<<<<<<<<<<<<<
@@ -12691,7 +12836,7 @@ static PyObject *__pyx_pf_5_cdec_14HypergraphNode___richcmp__(struct __pyx_obj_5
  */
     case 2:
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":269
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":278
  *     def __richcmp__(HypergraphNode x, HypergraphNode y, int op):
  *         if op == 2: # ==
  *             return x.node == y.node             # <<<<<<<<<<<<<<
@@ -12699,14 +12844,14 @@ static PyObject *__pyx_pf_5_cdec_14HypergraphNode___richcmp__(struct __pyx_obj_5
  *             return not (x == y)
  */
     __Pyx_XDECREF(__pyx_r);
-    __pyx_t_1 = __Pyx_PyBool_FromLong((__pyx_v_x->node == __pyx_v_y->node)); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 269; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    __pyx_t_1 = __Pyx_PyBool_FromLong((__pyx_v_x->node == __pyx_v_y->node)); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 278; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
     __Pyx_GOTREF(__pyx_t_1);
     __pyx_r = __pyx_t_1;
     __pyx_t_1 = 0;
     goto __pyx_L0;
     break;
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":270
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":279
  *         if op == 2: # ==
  *             return x.node == y.node
  *         elif op == 3: # !=             # <<<<<<<<<<<<<<
@@ -12715,17 +12860,17 @@ static PyObject *__pyx_pf_5_cdec_14HypergraphNode___richcmp__(struct __pyx_obj_5
  */
     case 3:
 
-    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":271
+    /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":280
  *             return x.node == y.node
  *         elif op == 3: # !=
  *             return not (x == y)             # <<<<<<<<<<<<<<
  *         raise NotImplemented('comparison not implemented for HypergraphNode')
  */
     __Pyx_XDECREF(__pyx_r);
-    __pyx_t_1 = PyObject_RichCompare(((PyObject *)__pyx_v_x), ((PyObject *)__pyx_v_y), Py_EQ); __Pyx_XGOTREF(__pyx_t_1); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 271; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
-    __pyx_t_2 = __Pyx_PyObject_IsTrue(__pyx_t_1); if (unlikely(__pyx_t_2 < 0)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 271; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    __pyx_t_1 = PyObject_RichCompare(((PyObject *)__pyx_v_x), ((PyObject *)__pyx_v_y), Py_EQ); __Pyx_XGOTREF(__pyx_t_1); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 280; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    __pyx_t_2 = __Pyx_PyObject_IsTrue(__pyx_t_1); if (unlikely(__pyx_t_2 < 0)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 280; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
     __Pyx_DECREF(__pyx_t_1); __pyx_t_1 = 0;
-    __pyx_t_1 = __Pyx_PyBool_FromLong((!__pyx_t_2)); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 271; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+    __pyx_t_1 = __Pyx_PyBool_FromLong((!__pyx_t_2)); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 280; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
     __Pyx_GOTREF(__pyx_t_1);
     __pyx_r = __pyx_t_1;
     __pyx_t_1 = 0;
@@ -12733,16 +12878,16 @@ static PyObject *__pyx_pf_5_cdec_14HypergraphNode___richcmp__(struct __pyx_obj_5
     break;
   }
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":272
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":281
  *         elif op == 3: # !=
  *             return not (x == y)
  *         raise NotImplemented('comparison not implemented for HypergraphNode')             # <<<<<<<<<<<<<<
  */
-  __pyx_t_1 = PyObject_Call(__pyx_builtin_NotImplemented, ((PyObject *)__pyx_k_tuple_21), NULL); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 272; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_t_1 = PyObject_Call(__pyx_builtin_NotImplemented, ((PyObject *)__pyx_k_tuple_21), NULL); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 281; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_GOTREF(__pyx_t_1);
   __Pyx_Raise(__pyx_t_1, 0, 0, 0);
   __Pyx_DECREF(__pyx_t_1); __pyx_t_1 = 0;
-  {__pyx_filename = __pyx_f[3]; __pyx_lineno = 272; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  {__pyx_filename = __pyx_f[3]; __pyx_lineno = 281; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
 
   __pyx_r = Py_None; __Pyx_INCREF(Py_None);
   goto __pyx_L0;
@@ -21157,18 +21302,19 @@ static PyMethodDef __pyx_methods_5_cdec_Hypergraph[] = {
   {__Pyx_NAMESTR("viterbi"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_3viterbi, METH_NOARGS, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_2viterbi)},
   {__Pyx_NAMESTR("viterbi_trees"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_5viterbi_trees, METH_NOARGS, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_4viterbi_trees)},
   {__Pyx_NAMESTR("viterbi_features"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_7viterbi_features, METH_NOARGS, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_6viterbi_features)},
-  {__Pyx_NAMESTR("viterbi_joshua"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_9viterbi_joshua, METH_NOARGS, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_8viterbi_joshua)},
-  {__Pyx_NAMESTR("kbest"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_11kbest, METH_O, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_10kbest)},
-  {__Pyx_NAMESTR("kbest_trees"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_14kbest_trees, METH_O, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_13kbest_trees)},
-  {__Pyx_NAMESTR("kbest_features"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_17kbest_features, METH_O, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_16kbest_features)},
-  {__Pyx_NAMESTR("sample"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_20sample, METH_O, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_19sample)},
-  {__Pyx_NAMESTR("sample_trees"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_23sample_trees, METH_O, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_22sample_trees)},
-  {__Pyx_NAMESTR("intersect"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_26intersect, METH_O, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_25intersect)},
-  {__Pyx_NAMESTR("prune"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_28prune, METH_VARARGS|METH_KEYWORDS, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_27prune)},
-  {__Pyx_NAMESTR("lattice"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_30lattice, METH_NOARGS, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_29lattice)},
-  {__Pyx_NAMESTR("plf"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_32plf, METH_NOARGS, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_31plf)},
-  {__Pyx_NAMESTR("reweight"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_34reweight, METH_O, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_33reweight)},
-  {__Pyx_NAMESTR("inside_outside"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_36inside_outside, METH_NOARGS, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_35inside_outside)},
+  {__Pyx_NAMESTR("viterbi_forest"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_9viterbi_forest, METH_NOARGS, __Pyx_DOCSTR(0)},
+  {__Pyx_NAMESTR("viterbi_joshua"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_11viterbi_joshua, METH_NOARGS, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_10viterbi_joshua)},
+  {__Pyx_NAMESTR("kbest"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_13kbest, METH_O, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_12kbest)},
+  {__Pyx_NAMESTR("kbest_trees"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_16kbest_trees, METH_O, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_15kbest_trees)},
+  {__Pyx_NAMESTR("kbest_features"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_19kbest_features, METH_O, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_18kbest_features)},
+  {__Pyx_NAMESTR("sample"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_22sample, METH_O, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_21sample)},
+  {__Pyx_NAMESTR("sample_trees"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_25sample_trees, METH_O, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_24sample_trees)},
+  {__Pyx_NAMESTR("intersect"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_28intersect, METH_O, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_27intersect)},
+  {__Pyx_NAMESTR("prune"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_30prune, METH_VARARGS|METH_KEYWORDS, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_29prune)},
+  {__Pyx_NAMESTR("lattice"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_32lattice, METH_NOARGS, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_31lattice)},
+  {__Pyx_NAMESTR("plf"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_34plf, METH_NOARGS, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_33plf)},
+  {__Pyx_NAMESTR("reweight"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_36reweight, METH_O, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_35reweight)},
+  {__Pyx_NAMESTR("inside_outside"), (PyCFunction)__pyx_pw_5_cdec_10Hypergraph_38inside_outside, METH_NOARGS, __Pyx_DOCSTR(__pyx_doc_5_cdec_10Hypergraph_37inside_outside)},
   {0, 0, 0, 0}
 };
 
@@ -21381,6 +21527,10 @@ static PyObject *__pyx_getprop_5_cdec_14HypergraphEdge_span(PyObject *o, CYTHON_
   return __pyx_pw_5_cdec_14HypergraphEdge_4span_1__get__(o);
 }
 
+static PyObject *__pyx_getprop_5_cdec_14HypergraphEdge_src_span(PyObject *o, CYTHON_UNUSED void *x) {
+  return __pyx_pw_5_cdec_14HypergraphEdge_8src_span_1__get__(o);
+}
+
 static PyObject *__pyx_getprop_5_cdec_14HypergraphEdge_feature_values(PyObject *o, CYTHON_UNUSED void *x) {
   return __pyx_pw_5_cdec_14HypergraphEdge_14feature_values_1__get__(o);
 }
@@ -21410,6 +21560,7 @@ static struct PyGetSetDef __pyx_getsets_5_cdec_HypergraphEdge[] = {
   {(char *)"head_node", __pyx_getprop_5_cdec_14HypergraphEdge_head_node, 0, 0, 0},
   {(char *)"tail_nodes", __pyx_getprop_5_cdec_14HypergraphEdge_tail_nodes, 0, 0, 0},
   {(char *)"span", __pyx_getprop_5_cdec_14HypergraphEdge_span, 0, 0, 0},
+  {(char *)"src_span", __pyx_getprop_5_cdec_14HypergraphEdge_src_span, 0, 0, 0},
   {(char *)"feature_values", __pyx_getprop_5_cdec_14HypergraphEdge_feature_values, 0, 0, 0},
   {(char *)"prob", __pyx_getprop_5_cdec_14HypergraphEdge_prob, 0, 0, 0},
   {(char *)"trule", __pyx_getprop_5_cdec_14HypergraphEdge_trule, __pyx_setprop_5_cdec_14HypergraphEdge_trule, 0, 0},
@@ -28670,8 +28821,8 @@ static int __Pyx_InitCachedBuiltins(void) {
   __pyx_builtin_NotImplemented = __Pyx_GetName(__pyx_b, __pyx_n_s__NotImplemented); if (!__pyx_builtin_NotImplemented) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 95; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_builtin_super = __Pyx_GetName(__pyx_b, __pyx_n_s__super); if (!__pyx_builtin_super) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 191; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_builtin_ValueError = __Pyx_GetName(__pyx_b, __pyx_n_s__ValueError); if (!__pyx_builtin_ValueError) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 226; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
-  __pyx_builtin_basestring = __Pyx_GetName(__pyx_b, __pyx_n_s__basestring); if (!__pyx_builtin_basestring) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 119; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
-  __pyx_builtin_eval = __Pyx_GetName(__pyx_b, __pyx_n_s__eval); if (!__pyx_builtin_eval) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 140; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_builtin_basestring = __Pyx_GetName(__pyx_b, __pyx_n_s__basestring); if (!__pyx_builtin_basestring) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 124; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_builtin_eval = __Pyx_GetName(__pyx_b, __pyx_n_s__eval); if (!__pyx_builtin_eval) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 145; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_builtin_enumerate = __Pyx_GetName(__pyx_b, __pyx_n_s__enumerate); if (!__pyx_builtin_enumerate) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 14; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_builtin_IndexError = __Pyx_GetName(__pyx_b, __pyx_n_s__IndexError); if (!__pyx_builtin_IndexError) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 26; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_builtin_open = __Pyx_GetName(__pyx_b, __pyx_n_s__open); if (!__pyx_builtin_open) {__pyx_filename = __pyx_f[0]; __pyx_lineno = 91; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
@@ -28739,26 +28890,26 @@ static int __Pyx_InitCachedConstants(void) {
   __Pyx_GIVEREF(((PyObject *)__pyx_kp_s_13));
   __Pyx_GIVEREF(((PyObject *)__pyx_k_tuple_14));
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":235
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":244
  *         elif op == 3: # !=
  *             return not (x == y)
  *         raise NotImplemented('comparison not implemented for HypergraphEdge')             # <<<<<<<<<<<<<<
  * 
  * cdef class HypergraphNode:
  */
-  __pyx_k_tuple_19 = PyTuple_New(1); if (unlikely(!__pyx_k_tuple_19)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 235; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_k_tuple_19 = PyTuple_New(1); if (unlikely(!__pyx_k_tuple_19)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 244; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_GOTREF(__pyx_k_tuple_19);
   __Pyx_INCREF(((PyObject *)__pyx_kp_s_18));
   PyTuple_SET_ITEM(__pyx_k_tuple_19, 0, ((PyObject *)__pyx_kp_s_18));
   __Pyx_GIVEREF(((PyObject *)__pyx_kp_s_18));
   __Pyx_GIVEREF(((PyObject *)__pyx_k_tuple_19));
 
-  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":272
+  /* "/home/vchahune/tools/cdec/python/src/hypergraph.pxi":281
  *         elif op == 3: # !=
  *             return not (x == y)
  *         raise NotImplemented('comparison not implemented for HypergraphNode')             # <<<<<<<<<<<<<<
  */
-  __pyx_k_tuple_21 = PyTuple_New(1); if (unlikely(!__pyx_k_tuple_21)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 272; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_k_tuple_21 = PyTuple_New(1); if (unlikely(!__pyx_k_tuple_21)) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 281; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_GOTREF(__pyx_k_tuple_21);
   __Pyx_INCREF(((PyObject *)__pyx_kp_s_20));
   PyTuple_SET_ITEM(__pyx_k_tuple_21, 0, ((PyObject *)__pyx_kp_s_20));
@@ -29215,15 +29366,15 @@ PyMODINIT_FUNC PyInit__cdec(void)
   __pyx_ptype_5_cdec_Hypergraph = &__pyx_type_5_cdec_Hypergraph;
   __pyx_vtabptr_5_cdec_HypergraphEdge = &__pyx_vtable_5_cdec_HypergraphEdge;
   __pyx_vtable_5_cdec_HypergraphEdge.init = (PyObject *(*)(struct __pyx_obj_5_cdec_HypergraphEdge *, Hypergraph *, unsigned int))__pyx_f_5_cdec_14HypergraphEdge_init;
-  if (PyType_Ready(&__pyx_type_5_cdec_HypergraphEdge) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 191; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
-  if (__Pyx_SetVtable(__pyx_type_5_cdec_HypergraphEdge.tp_dict, __pyx_vtabptr_5_cdec_HypergraphEdge) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 191; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
-  if (__Pyx_SetAttrString(__pyx_m, "HypergraphEdge", (PyObject *)&__pyx_type_5_cdec_HypergraphEdge) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 191; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec_HypergraphEdge) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 196; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (__Pyx_SetVtable(__pyx_type_5_cdec_HypergraphEdge.tp_dict, __pyx_vtabptr_5_cdec_HypergraphEdge) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 196; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (__Pyx_SetAttrString(__pyx_m, "HypergraphEdge", (PyObject *)&__pyx_type_5_cdec_HypergraphEdge) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 196; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec_HypergraphEdge = &__pyx_type_5_cdec_HypergraphEdge;
   __pyx_vtabptr_5_cdec_HypergraphNode = &__pyx_vtable_5_cdec_HypergraphNode;
   __pyx_vtable_5_cdec_HypergraphNode.init = (PyObject *(*)(struct __pyx_obj_5_cdec_HypergraphNode *, Hypergraph *, unsigned int))__pyx_f_5_cdec_14HypergraphNode_init;
-  if (PyType_Ready(&__pyx_type_5_cdec_HypergraphNode) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 237; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
-  if (__Pyx_SetVtable(__pyx_type_5_cdec_HypergraphNode.tp_dict, __pyx_vtabptr_5_cdec_HypergraphNode) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 237; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
-  if (__Pyx_SetAttrString(__pyx_m, "HypergraphNode", (PyObject *)&__pyx_type_5_cdec_HypergraphNode) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 237; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec_HypergraphNode) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 246; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (__Pyx_SetVtable(__pyx_type_5_cdec_HypergraphNode.tp_dict, __pyx_vtabptr_5_cdec_HypergraphNode) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 246; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (__Pyx_SetAttrString(__pyx_m, "HypergraphNode", (PyObject *)&__pyx_type_5_cdec_HypergraphNode) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 246; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec_HypergraphNode = &__pyx_type_5_cdec_HypergraphNode;
   if (PyType_Ready(&__pyx_type_5_cdec_Lattice) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 3; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   #if CYTHON_COMPILING_IN_CPYTHON
@@ -29285,25 +29436,25 @@ PyMODINIT_FUNC PyInit__cdec(void)
   __pyx_ptype_5_cdec___pyx_scope_struct_6_genexpr = &__pyx_type_5_cdec___pyx_scope_struct_6_genexpr;
   if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_7___iter__) < 0) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 199; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_7___iter__ = &__pyx_type_5_cdec___pyx_scope_struct_7___iter__;
-  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_8_kbest) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 44; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_8_kbest) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 49; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_8_kbest = &__pyx_type_5_cdec___pyx_scope_struct_8_kbest;
-  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_9_kbest_trees) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 57; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_9_kbest_trees) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 62; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_9_kbest_trees = &__pyx_type_5_cdec___pyx_scope_struct_9_kbest_trees;
-  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_10_kbest_features) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 76; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_10_kbest_features) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 81; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_10_kbest_features = &__pyx_type_5_cdec___pyx_scope_struct_10_kbest_features;
-  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_11_sample) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 92; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_11_sample) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 97; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_11_sample = &__pyx_type_5_cdec___pyx_scope_struct_11_sample;
-  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_12_sample_trees) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 103; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_12_sample_trees) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 108; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_12_sample_trees = &__pyx_type_5_cdec___pyx_scope_struct_12_sample_trees;
-  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_13___get__) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 156; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_13___get__) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 161; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_13___get__ = &__pyx_type_5_cdec___pyx_scope_struct_13___get__;
-  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_14___get__) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 162; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_14___get__) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 167; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_14___get__ = &__pyx_type_5_cdec___pyx_scope_struct_14___get__;
-  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_15___get__) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 211; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_15___get__) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 216; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_15___get__ = &__pyx_type_5_cdec___pyx_scope_struct_15___get__;
-  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_16___get__) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 247; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_16___get__) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 256; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_16___get__ = &__pyx_type_5_cdec___pyx_scope_struct_16___get__;
-  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_17___get__) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 253; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_17___get__) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 262; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_17___get__ = &__pyx_type_5_cdec___pyx_scope_struct_17___get__;
   if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_18___iter__) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 56; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_18___iter__ = &__pyx_type_5_cdec___pyx_scope_struct_18___iter__;
diff --git a/python/src/hypergraph.pxd b/python/src/hypergraph.pxd
index dd3d39cc..1e150bbc 100644
--- a/python/src/hypergraph.pxd
+++ b/python/src/hypergraph.pxd
@@ -19,6 +19,8 @@ cdef extern from "decoder/hg.h":
         # typically source span:
         short int i_
         short int j_
+        short int prev_i_
+        short int prev_j_
 
     ctypedef HypergraphEdge const_HypergraphEdge "const Hypergraph::Edge"
 
@@ -45,6 +47,7 @@ cdef extern from "decoder/hg.h":
                                 bint use_sum_prod_semiring,
                                 double scale,
                                 bint safe_inside) nogil
+        shared_ptr[Hypergraph] CreateViterbiHypergraph(EdgeMask* preserve_mask) nogil
 
 cdef extern from "decoder/viterbi.h":
     prob_t ViterbiESentence(Hypergraph& hg, vector[WordID]* trans) nogil
diff --git a/python/src/hypergraph.pxi b/python/src/hypergraph.pxi
index 5b675531..4a709d32 100644
--- a/python/src/hypergraph.pxi
+++ b/python/src/hypergraph.pxi
@@ -37,6 +37,11 @@ cdef class Hypergraph:
         fmap.vector = new FastSparseVector[weight_t](hypergraph.ViterbiFeatures(self.hg[0]))
         return fmap
 
+    def viterbi_forest(self):
+        cdef Hypergraph hg = Hypergraph()
+        hg.hg = new hypergraph.Hypergraph(self.hg[0].CreateViterbiHypergraph(NULL).get()[0])
+        return hg
+
     def viterbi_joshua(self):
         """hg.viterbi_joshua() -> Joshua representation of the best derivation."""
         return unicode(hypergraph.JoshuaVisualizationString(self.hg[0]).c_str(), 'utf8')
@@ -217,6 +222,10 @@ cdef class HypergraphEdge:
         def __get__(self):
             return (self.edge.i_, self.edge.j_)
 
+    property src_span:
+        def __get__(self):
+            return (self.edge.prev_i_, self.edge.prev_j_)
+
     property feature_values:
         def __get__(self):
             cdef SparseVector vector = SparseVector.__new__(SparseVector)