[python] Explicit candidate set; memory leak fixes

5 files changed, 2200 insertions, 1250 deletions

diff --git a/python/src/_cdec.cpp b/python/src/_cdec.cpp
index 7d45e27f..bc522b32 100644
--- a/python/src/_cdec.cpp
+++ b/python/src/_cdec.cpp
@@ -1,4 +1,4 @@
-/* Generated by Cython 0.16 on Sun Jul  1 00:36:19 2012 */
+/* Generated by Cython 0.16 on Mon Jul  2 17:01:11 2012 */
 
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
@@ -389,12 +389,12 @@ static const char *__pyx_f[] = {
 
 /*--- Type declarations ---*/
 struct __pyx_obj_5_cdec_Scorer;
+struct __pyx_obj_5_cdec_CandidateSet;
 struct __pyx_obj_5_cdec_SufficientStats;
 struct __pyx_obj_5_cdec___pyx_scope_struct_1___iter__;
 struct __pyx_obj_5_cdec___pyx_scope_struct_4_kbest_features;
 struct __pyx_obj_5_cdec___pyx_scope_struct_3_kbest_tree;
 struct __pyx_obj_5_cdec_Decoder;
-struct __pyx_obj_5_cdec___pyx_scope_struct_8_candidate_set;
 struct __pyx_obj_5_cdec_SegmentEvaluator;
 struct __pyx_obj_5_cdec_SparseVector;
 struct __pyx_obj_5_cdec_Hypergraph;
@@ -405,6 +405,7 @@ struct __pyx_obj_5_cdec_Candidate;
 struct __pyx_obj_5_cdec___pyx_scope_struct_5_sample;
 struct __pyx_obj_5_cdec_DenseVector;
 struct __pyx_obj_5_cdec___pyx_scope_struct_6___iter__;
+struct __pyx_obj_5_cdec___pyx_scope_struct_8___iter__;
 struct __pyx_obj_5_cdec___pyx_scope_struct_7___iter__;
 struct __pyx_opt_args_5_cdec_as_str;
 
@@ -420,8 +421,8 @@ struct __pyx_opt_args_5_cdec_as_str {
   PyObject *error_msg;
 };
 
-/* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":87
- *         del cs
+/* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":109
+ *         return CandidateSet(self)
  * 
  * cdef class Scorer:             # <<<<<<<<<<<<<<
  *     cdef string* name
@@ -433,6 +434,21 @@ struct __pyx_obj_5_cdec_Scorer {
 };
 
 
+/* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":59
+ *         return result
+ * 
+ * cdef class CandidateSet:             # <<<<<<<<<<<<<<
+ *     cdef shared_ptr[mteval.SegmentEvaluator]* scorer
+ *     cdef mteval.EvaluationMetric* metric
+ */
+struct __pyx_obj_5_cdec_CandidateSet {
+  PyObject_HEAD
+  boost::shared_ptr<SegmentEvaluator> *scorer;
+  EvaluationMetric *metric;
+  training::CandidateSet *cs;
+};
+
+
 /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":27
  *             return fmap
  * 
@@ -447,16 +463,15 @@ struct __pyx_obj_5_cdec_SufficientStats {
 };
 
 
-/* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":43
+/* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":55
  *         self.vector.set_value(fid, value)
  * 
  *     def __iter__(self):             # <<<<<<<<<<<<<<
  *         cdef FastSparseVector[weight_t].const_iterator* it = new FastSparseVector[weight_t].const_iterator(self.vector[0], False)
- *         cdef str fname
+ *         try:
  */
 struct __pyx_obj_5_cdec___pyx_scope_struct_1___iter__ {
   PyObject_HEAD
-  PyObject *__pyx_v_fname;
   size_t __pyx_v_i;
   FastSparseVector<weight_t>::const_iterator *__pyx_v_it;
   struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self;
@@ -465,8 +480,8 @@ struct __pyx_obj_5_cdec___pyx_scope_struct_1___iter__ {
 };
 
 
-/* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":56
- *         del derivations
+/* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":60
+ *             del derivations
  * 
  *     def kbest_features(self, size):             # <<<<<<<<<<<<<<
  *         cdef kb.KBestDerivations[FastSparseVector[weight_t], kb.FeatureVectorTraversal]* derivations = new kb.KBestDerivations[FastSparseVector[weight_t], kb.FeatureVectorTraversal](self.hg[0], size)
@@ -485,8 +500,8 @@ struct __pyx_obj_5_cdec___pyx_scope_struct_4_kbest_features {
 };
 
 
-/* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":44
- *         del derivations
+/* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":46
+ *             del derivations
  * 
  *     def kbest_tree(self, size):             # <<<<<<<<<<<<<<
  *         cdef kb.KBestDerivations[vector[WordID], kb.ETreeTraversal]* derivations = new kb.KBestDerivations[vector[WordID], kb.ETreeTraversal](self.hg[0], size)
@@ -519,28 +534,8 @@ struct __pyx_obj_5_cdec_Decoder {
 };
 
 
-/* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":75
- *         return sf
- * 
- *     def candidate_set(self, Hypergraph hypergraph, unsigned k):             # <<<<<<<<<<<<<<
- *         cdef mteval.CandidateSet* cs = new mteval.CandidateSet()
- *         cs.AddKBestCandidates(hypergraph.hg[0], k, self.scorer.get())
- */
-struct __pyx_obj_5_cdec___pyx_scope_struct_8_candidate_set {
-  PyObject_HEAD
-  struct __pyx_obj_5_cdec_Candidate *__pyx_v_candidate;
-  training::CandidateSet *__pyx_v_cs;
-  struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_hypergraph;
-  unsigned int __pyx_v_i;
-  unsigned int __pyx_v_k;
-  struct __pyx_obj_5_cdec_SegmentEvaluator *__pyx_v_self;
-  unsigned int __pyx_t_0;
-  unsigned int __pyx_t_1;
-};
-
-
-/* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":59
- *         return result
+/* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":90
+ *         self.cs.AddKBestCandidates(hypergraph.hg[0], k, self.scorer.get())
  * 
  * cdef class SegmentEvaluator:             # <<<<<<<<<<<<<<
  *     cdef shared_ptr[mteval.SegmentEvaluator]* scorer
@@ -553,7 +548,7 @@ struct __pyx_obj_5_cdec_SegmentEvaluator {
 };
 
 
-/* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":32
+/* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":36
  *         return sparse
  * 
  * cdef class SparseVector:             # <<<<<<<<<<<<<<
@@ -593,7 +588,7 @@ struct __pyx_obj_5_cdec_Lattice {
 };
 
 
-/* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":18
+/* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":22
  *         self.vector[0][fid] = value
  * 
  *     def __iter__(self):             # <<<<<<<<<<<<<<
@@ -643,8 +638,8 @@ struct __pyx_obj_5_cdec_Candidate {
 };
 
 
-/* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":69
- *         del derivations
+/* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":75
+ *             del derivations
  * 
  *     def sample(self, unsigned n):             # <<<<<<<<<<<<<<
  *         cdef vector[hypergraph.Hypothesis]* hypos = new vector[hypergraph.Hypothesis]()
@@ -666,7 +661,7 @@ struct __pyx_obj_5_cdec___pyx_scope_struct_5_sample {
  * from cython.operator cimport preincrement as pinc
  * 
  * cdef class DenseVector:             # <<<<<<<<<<<<<<
- *     cdef vector[weight_t]* vector
+ *     cdef vector[weight_t]* vector # Not owned by DenseVector
  * 
  */
 struct __pyx_obj_5_cdec_DenseVector {
@@ -691,6 +686,22 @@ struct __pyx_obj_5_cdec___pyx_scope_struct_6___iter__ {
 };
 
 
+/* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":82
+ *         return candidate
+ * 
+ *     def __iter__(self):             # <<<<<<<<<<<<<<
+ *         cdef unsigned i
+ *         for i in range(len(self)):
+ */
+struct __pyx_obj_5_cdec___pyx_scope_struct_8___iter__ {
+  PyObject_HEAD
+  unsigned int __pyx_v_i;
+  struct __pyx_obj_5_cdec_CandidateSet *__pyx_v_self;
+  Py_ssize_t __pyx_t_0;
+  unsigned int __pyx_t_1;
+};
+
+
 /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":45
  *         return self.stats.size()
  * 
@@ -989,6 +1000,7 @@ static PyTypeObject *__pyx_ptype_5_cdec_Hypergraph = 0;
 static PyTypeObject *__pyx_ptype_5_cdec_Lattice = 0;
 static PyTypeObject *__pyx_ptype_5_cdec_Candidate = 0;
 static PyTypeObject *__pyx_ptype_5_cdec_SufficientStats = 0;
+static PyTypeObject *__pyx_ptype_5_cdec_CandidateSet = 0;
 static PyTypeObject *__pyx_ptype_5_cdec_SegmentEvaluator = 0;
 static PyTypeObject *__pyx_ptype_5_cdec_Scorer = 0;
 static PyTypeObject *__pyx_ptype_5_cdec_Decoder = 0;
@@ -1000,7 +1012,7 @@ static PyTypeObject *__pyx_ptype_5_cdec___pyx_scope_struct_4_kbest_features = 0;
 static PyTypeObject *__pyx_ptype_5_cdec___pyx_scope_struct_5_sample = 0;
 static PyTypeObject *__pyx_ptype_5_cdec___pyx_scope_struct_6___iter__ = 0;
 static PyTypeObject *__pyx_ptype_5_cdec___pyx_scope_struct_7___iter__ = 0;
-static PyTypeObject *__pyx_ptype_5_cdec___pyx_scope_struct_8_candidate_set = 0;
+static PyTypeObject *__pyx_ptype_5_cdec___pyx_scope_struct_8___iter__ = 0;
 static char *__pyx_f_5_cdec_as_str(PyObject *, struct __pyx_opt_args_5_cdec_as_str *__pyx_optional_args); /*proto*/
 #define __Pyx_MODULE_NAME "_cdec"
 int __pyx_module_is_main__cdec = 0;
@@ -1015,30 +1027,32 @@ static PyObject *__pyx_builtin_eval;
 static PyObject *__pyx_builtin_enumerate;
 static PyObject *__pyx_builtin_IndexError;
 static PyObject *__pyx_builtin_open;
-static PyObject *__pyx_pf_5_cdec_11DenseVector___getitem__(struct __pyx_obj_5_cdec_DenseVector *__pyx_v_self, char *__pyx_v_fname); /* proto */
-static int __pyx_pf_5_cdec_11DenseVector_2__setitem__(struct __pyx_obj_5_cdec_DenseVector *__pyx_v_self, char *__pyx_v_fname, float __pyx_v_value); /* proto */
-static PyObject *__pyx_pf_5_cdec_11DenseVector_4__iter__(struct __pyx_obj_5_cdec_DenseVector *__pyx_v_self); /* proto */
-static PyObject *__pyx_pf_5_cdec_11DenseVector_7dot(struct __pyx_obj_5_cdec_DenseVector *__pyx_v_self, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_other); /* proto */
-static PyObject *__pyx_pf_5_cdec_11DenseVector_9tosparse(struct __pyx_obj_5_cdec_DenseVector *__pyx_v_self); /* proto */
-static PyObject *__pyx_pf_5_cdec_12SparseVector___getitem__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, char *__pyx_v_fname); /* proto */
-static int __pyx_pf_5_cdec_12SparseVector_2__setitem__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, char *__pyx_v_fname, float __pyx_v_value); /* proto */
-static PyObject *__pyx_pf_5_cdec_12SparseVector_4__iter__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self); /* proto */
-static PyObject *__pyx_pf_5_cdec_12SparseVector_7dot(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, PyObject *__pyx_v_other); /* proto */
-static PyObject *__pyx_pf_5_cdec_12SparseVector_9todense(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self); /* proto */
-static PyObject *__pyx_pf_5_cdec_12SparseVector_11__richcmp__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_x, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_y, int __pyx_v_op); /* proto */
-static Py_ssize_t __pyx_pf_5_cdec_12SparseVector_13__len__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self); /* proto */
-static int __pyx_pf_5_cdec_12SparseVector_15__contains__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, char *__pyx_v_fname); /* proto */
-static PyObject *__pyx_pf_5_cdec_12SparseVector_17__iadd__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_other); /* proto */
-static PyObject *__pyx_pf_5_cdec_12SparseVector_19__isub__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_other); /* proto */
-static PyObject *__pyx_pf_5_cdec_12SparseVector_21__imul__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, float __pyx_v_scalar); /* proto */
+static Py_ssize_t __pyx_pf_5_cdec_11DenseVector___len__(struct __pyx_obj_5_cdec_DenseVector *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_5_cdec_11DenseVector_2__getitem__(struct __pyx_obj_5_cdec_DenseVector *__pyx_v_self, char *__pyx_v_fname); /* proto */
+static int __pyx_pf_5_cdec_11DenseVector_4__setitem__(struct __pyx_obj_5_cdec_DenseVector *__pyx_v_self, char *__pyx_v_fname, float __pyx_v_value); /* proto */
+static PyObject *__pyx_pf_5_cdec_11DenseVector_6__iter__(struct __pyx_obj_5_cdec_DenseVector *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_5_cdec_11DenseVector_9dot(struct __pyx_obj_5_cdec_DenseVector *__pyx_v_self, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_other); /* proto */
+static PyObject *__pyx_pf_5_cdec_11DenseVector_11tosparse(struct __pyx_obj_5_cdec_DenseVector *__pyx_v_self); /* proto */
+static void __pyx_pf_5_cdec_12SparseVector___dealloc__(CYTHON_UNUSED struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_5_cdec_12SparseVector_2copy(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_5_cdec_12SparseVector_4__getitem__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, char *__pyx_v_fname); /* proto */
+static int __pyx_pf_5_cdec_12SparseVector_6__setitem__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, char *__pyx_v_fname, float __pyx_v_value); /* proto */
+static PyObject *__pyx_pf_5_cdec_12SparseVector_8__iter__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_5_cdec_12SparseVector_11dot(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, PyObject *__pyx_v_other); /* proto */
+static PyObject *__pyx_pf_5_cdec_12SparseVector_13__richcmp__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_x, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_y, int __pyx_v_op); /* proto */
+static Py_ssize_t __pyx_pf_5_cdec_12SparseVector_15__len__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self); /* proto */
+static int __pyx_pf_5_cdec_12SparseVector_17__contains__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, char *__pyx_v_fname); /* proto */
+static PyObject *__pyx_pf_5_cdec_12SparseVector_19__iadd__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_other); /* proto */
+static PyObject *__pyx_pf_5_cdec_12SparseVector_21__isub__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_other); /* proto */
+static PyObject *__pyx_pf_5_cdec_12SparseVector_23__imul__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, float __pyx_v_scalar); /* proto */
 #if PY_MAJOR_VERSION < 3
-static PyObject *__pyx_pf_5_cdec_12SparseVector_23__idiv__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, float __pyx_v_scalar); /* proto */
+static PyObject *__pyx_pf_5_cdec_12SparseVector_25__idiv__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, float __pyx_v_scalar); /* proto */
 #endif
-static PyObject *__pyx_pf_5_cdec_12SparseVector_25__add__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_x, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_y); /* proto */
-static PyObject *__pyx_pf_5_cdec_12SparseVector_27__sub__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_x, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_y); /* proto */
-static PyObject *__pyx_pf_5_cdec_12SparseVector_29__mul__(PyObject *__pyx_v_x, PyObject *__pyx_v_y); /* proto */
+static PyObject *__pyx_pf_5_cdec_12SparseVector_27__add__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_x, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_y); /* proto */
+static PyObject *__pyx_pf_5_cdec_12SparseVector_29__sub__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_x, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_y); /* proto */
+static PyObject *__pyx_pf_5_cdec_12SparseVector_31__mul__(PyObject *__pyx_v_x, PyObject *__pyx_v_y); /* proto */
 #if PY_MAJOR_VERSION < 3
-static PyObject *__pyx_pf_5_cdec_12SparseVector_31__div__(PyObject *__pyx_v_x, PyObject *__pyx_v_y); /* proto */
+static PyObject *__pyx_pf_5_cdec_12SparseVector_33__div__(PyObject *__pyx_v_x, PyObject *__pyx_v_y); /* proto */
 #endif
 static void __pyx_pf_5_cdec_10Hypergraph___dealloc__(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_5_cdec_10Hypergraph_2viterbi(struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_self); /* proto */
@@ -1071,12 +1085,19 @@ static Py_ssize_t __pyx_pf_5_cdec_15SufficientStats_2__len__(struct __pyx_obj_5_
 static PyObject *__pyx_pf_5_cdec_15SufficientStats_4__iter__(struct __pyx_obj_5_cdec_SufficientStats *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_5_cdec_15SufficientStats_7__iadd__(struct __pyx_obj_5_cdec_SufficientStats *__pyx_v_self, struct __pyx_obj_5_cdec_SufficientStats *__pyx_v_other); /* proto */
 static PyObject *__pyx_pf_5_cdec_15SufficientStats_9__add__(struct __pyx_obj_5_cdec_SufficientStats *__pyx_v_x, struct __pyx_obj_5_cdec_SufficientStats *__pyx_v_y); /* proto */
+static int __pyx_pf_5_cdec_12CandidateSet___cinit__(struct __pyx_obj_5_cdec_CandidateSet *__pyx_v_self, struct __pyx_obj_5_cdec_SegmentEvaluator *__pyx_v_evaluator); /* proto */
+static void __pyx_pf_5_cdec_12CandidateSet_2__dealloc__(CYTHON_UNUSED struct __pyx_obj_5_cdec_CandidateSet *__pyx_v_self); /* proto */
+static Py_ssize_t __pyx_pf_5_cdec_12CandidateSet_4__len__(struct __pyx_obj_5_cdec_CandidateSet *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_5_cdec_12CandidateSet_6__getitem__(struct __pyx_obj_5_cdec_CandidateSet *__pyx_v_self, unsigned int __pyx_v_k); /* proto */
+static PyObject *__pyx_pf_5_cdec_12CandidateSet_8__iter__(struct __pyx_obj_5_cdec_CandidateSet *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_5_cdec_12CandidateSet_11add_kbest(struct __pyx_obj_5_cdec_CandidateSet *__pyx_v_self, struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_hypergraph, unsigned int __pyx_v_k); /* proto */
 static void __pyx_pf_5_cdec_16SegmentEvaluator___dealloc__(CYTHON_UNUSED struct __pyx_obj_5_cdec_SegmentEvaluator *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_5_cdec_16SegmentEvaluator_2evaluate(struct __pyx_obj_5_cdec_SegmentEvaluator *__pyx_v_self, PyObject *__pyx_v_sentence); /* proto */
-static PyObject *__pyx_pf_5_cdec_16SegmentEvaluator_4candidate_set(struct __pyx_obj_5_cdec_SegmentEvaluator *__pyx_v_self, struct __pyx_obj_5_cdec_Hypergraph *__pyx_v_hypergraph, unsigned int __pyx_v_k); /* proto */
+static PyObject *__pyx_pf_5_cdec_16SegmentEvaluator_4candidate_set(struct __pyx_obj_5_cdec_SegmentEvaluator *__pyx_v_self); /* proto */
 static int __pyx_pf_5_cdec_6Scorer___cinit__(struct __pyx_obj_5_cdec_Scorer *__pyx_v_self, char *__pyx_v_name); /* proto */
-static PyObject *__pyx_pf_5_cdec_6Scorer_2__call__(struct __pyx_obj_5_cdec_Scorer *__pyx_v_self, PyObject *__pyx_v_refs); /* proto */
-static PyObject *__pyx_pf_5_cdec_6Scorer_4__str__(struct __pyx_obj_5_cdec_Scorer *__pyx_v_self); /* proto */
+static void __pyx_pf_5_cdec_6Scorer_2__dealloc__(CYTHON_UNUSED struct __pyx_obj_5_cdec_Scorer *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_5_cdec_6Scorer_4__call__(struct __pyx_obj_5_cdec_Scorer *__pyx_v_self, PyObject *__pyx_v_refs); /* proto */
+static PyObject *__pyx_pf_5_cdec_6Scorer_6__str__(struct __pyx_obj_5_cdec_Scorer *__pyx_v_self); /* proto */
 static int __pyx_pf_5_cdec_7Decoder___cinit__(struct __pyx_obj_5_cdec_Decoder *__pyx_v_self, char *__pyx_v_config); /* proto */
 static void __pyx_pf_5_cdec_7Decoder_2__dealloc__(CYTHON_UNUSED struct __pyx_obj_5_cdec_Decoder *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_5_cdec_7Decoder_4read_weights(struct __pyx_obj_5_cdec_Decoder *__pyx_v_self, PyObject *__pyx_v_cfg); /* proto */
@@ -1124,6 +1145,7 @@ static char __pyx_k__Exception[] = "Exception";
 static char __pyx_k__TypeError[] = "TypeError";
 static char __pyx_k____enter__[] = "__enter__";
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 static char __pyx_k__beam_alpha[] = "beam_alpha";
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 static PyObject *__pyx_n_s__encoding;
 static PyObject *__pyx_n_s__enumerate;
 static PyObject *__pyx_n_s__eval;
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 static PyObject *__pyx_n_s__grammar;
 static PyObject *__pyx_n_s__hypergraph;
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+static Py_ssize_t __pyx_pw_5_cdec_11DenseVector_1__len__(PyObject *__pyx_v_self) {
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+static Py_ssize_t __pyx_pf_5_cdec_11DenseVector___len__(struct __pyx_obj_5_cdec_DenseVector *__pyx_v_self) {
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+    /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":12
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-static PyObject *__pyx_pf_5_cdec_11DenseVector_4__iter__(struct __pyx_obj_5_cdec_DenseVector *__pyx_v_self) {
+static PyObject *__pyx_pf_5_cdec_11DenseVector_6__iter__(struct __pyx_obj_5_cdec_DenseVector *__pyx_v_self) {
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 }
 
-static PyObject *__pyx_gb_5_cdec_11DenseVector_6generator(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value) /* generator body */
+static PyObject *__pyx_gb_5_cdec_11DenseVector_8generator(__pyx_GeneratorObject *__pyx_generator, PyObject *__pyx_sent_value) /* generator body */
 {
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+  if (unlikely(!__pyx_sent_value)) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 22; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
 
-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":20
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-    /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":21
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+    __pyx_t_3 = PyBytes_FromString(FD::Convert(__pyx_cur_scope->__pyx_v_fid).c_str()); if (unlikely(!__pyx_t_3)) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 25; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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+    __pyx_t_5 = PyTuple_New(2); if (unlikely(!__pyx_t_5)) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 25; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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+  __pyx_r = __pyx_pf_5_cdec_11DenseVector_9dot(((struct __pyx_obj_5_cdec_DenseVector *)__pyx_v_self), ((struct __pyx_obj_5_cdec_SparseVector *)__pyx_v_other));
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-/* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":23
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+static PyObject *__pyx_pf_5_cdec_11DenseVector_9dot(struct __pyx_obj_5_cdec_DenseVector *__pyx_v_self, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_other) {
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":24
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":67
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-    /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":65
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+  __pyx_r = __pyx_pf_5_cdec_12SparseVector_21__isub__(((struct __pyx_obj_5_cdec_SparseVector *)__pyx_v_self), ((struct __pyx_obj_5_cdec_SparseVector *)__pyx_v_other));
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@@ -2474,7 +2683,7 @@ static PyObject *__pyx_pw_5_cdec_12SparseVector_20__isub__(PyObject *__pyx_v_sel
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 }
 
-/* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":81
+/* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":88
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-static PyObject *__pyx_pf_5_cdec_12SparseVector_19__isub__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_other) {
+static PyObject *__pyx_pf_5_cdec_12SparseVector_21__isub__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_other) {
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":82
+  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":89
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":83
+  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":90
  *     def __isub__(SparseVector self, SparseVector other):
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@@ -2516,14 +2725,14 @@ static PyObject *__pyx_pf_5_cdec_12SparseVector_19__isub__(struct __pyx_obj_5_cd
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-static PyObject *__pyx_pw_5_cdec_12SparseVector_22__imul__(PyObject *__pyx_v_self, PyObject *__pyx_arg_scalar) {
+static PyObject *__pyx_pw_5_cdec_12SparseVector_24__imul__(PyObject *__pyx_v_self, PyObject *__pyx_arg_scalar); /*proto*/
+static PyObject *__pyx_pw_5_cdec_12SparseVector_24__imul__(PyObject *__pyx_v_self, PyObject *__pyx_arg_scalar) {
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+    __pyx_v_scalar = __pyx_PyFloat_AsFloat(__pyx_arg_scalar); if (unlikely((__pyx_v_scalar == (float)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 92; __pyx_clineno = __LINE__; goto __pyx_L3_error;}
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@@ -2531,12 +2740,12 @@ static PyObject *__pyx_pw_5_cdec_12SparseVector_22__imul__(PyObject *__pyx_v_sel
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+  __pyx_r = __pyx_pf_5_cdec_12SparseVector_23__imul__(((struct __pyx_obj_5_cdec_SparseVector *)__pyx_v_self), ((float)__pyx_v_scalar));
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-/* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":85
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-static PyObject *__pyx_pf_5_cdec_12SparseVector_21__imul__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, float __pyx_v_scalar) {
+static PyObject *__pyx_pf_5_cdec_12SparseVector_23__imul__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, float __pyx_v_scalar) {
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":86
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":87
+  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":94
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-static PyObject *__pyx_pw_5_cdec_12SparseVector_24__idiv__(PyObject *__pyx_v_self, PyObject *__pyx_arg_scalar) {
+static PyObject *__pyx_pw_5_cdec_12SparseVector_26__idiv__(PyObject *__pyx_v_self, PyObject *__pyx_arg_scalar); /*proto*/
+static PyObject *__pyx_pw_5_cdec_12SparseVector_26__idiv__(PyObject *__pyx_v_self, PyObject *__pyx_arg_scalar) {
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+    __pyx_v_scalar = __pyx_PyFloat_AsFloat(__pyx_arg_scalar); if (unlikely((__pyx_v_scalar == (float)-1) && PyErr_Occurred())) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 96; __pyx_clineno = __LINE__; goto __pyx_L3_error;}
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+  __pyx_r = __pyx_pf_5_cdec_12SparseVector_25__idiv__(((struct __pyx_obj_5_cdec_SparseVector *)__pyx_v_self), ((float)__pyx_v_scalar));
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-/* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":89
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-static PyObject *__pyx_pf_5_cdec_12SparseVector_23__idiv__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, float __pyx_v_scalar) {
+static PyObject *__pyx_pf_5_cdec_12SparseVector_25__idiv__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_self, float __pyx_v_scalar) {
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":90
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":91
+  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":98
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-static PyObject *__pyx_pw_5_cdec_12SparseVector_26__add__(PyObject *__pyx_v_x, PyObject *__pyx_v_y) {
+static PyObject *__pyx_pw_5_cdec_12SparseVector_28__add__(PyObject *__pyx_v_x, PyObject *__pyx_v_y); /*proto*/
+static PyObject *__pyx_pw_5_cdec_12SparseVector_28__add__(PyObject *__pyx_v_x, PyObject *__pyx_v_y) {
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+  if (unlikely(!__Pyx_ArgTypeTest(((PyObject *)__pyx_v_x), __pyx_ptype_5_cdec_SparseVector, 1, "x", 0))) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 100; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (unlikely(!__Pyx_ArgTypeTest(((PyObject *)__pyx_v_y), __pyx_ptype_5_cdec_SparseVector, 1, "y", 0))) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 100; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_r = __pyx_pf_5_cdec_12SparseVector_27__add__(((struct __pyx_obj_5_cdec_SparseVector *)__pyx_v_x), ((struct __pyx_obj_5_cdec_SparseVector *)__pyx_v_y));
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-/* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":93
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-static PyObject *__pyx_pf_5_cdec_12SparseVector_25__add__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_x, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_y) {
+static PyObject *__pyx_pf_5_cdec_12SparseVector_27__add__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_x, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_y) {
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":94
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+  __pyx_t_1 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_SparseVector)), ((PyObject *)__pyx_empty_tuple), NULL); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 101; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":95
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":96
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+  if (unlikely(!__Pyx_ArgTypeTest(((PyObject *)__pyx_v_x), __pyx_ptype_5_cdec_SparseVector, 1, "x", 0))) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 105; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (unlikely(!__Pyx_ArgTypeTest(((PyObject *)__pyx_v_y), __pyx_ptype_5_cdec_SparseVector, 1, "y", 0))) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 105; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_r = __pyx_pf_5_cdec_12SparseVector_29__sub__(((struct __pyx_obj_5_cdec_SparseVector *)__pyx_v_x), ((struct __pyx_obj_5_cdec_SparseVector *)__pyx_v_y));
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-/* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":98
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+static PyObject *__pyx_pf_5_cdec_12SparseVector_29__sub__(struct __pyx_obj_5_cdec_SparseVector *__pyx_v_x, struct __pyx_obj_5_cdec_SparseVector *__pyx_v_y) {
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":99
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+  __pyx_t_1 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_SparseVector)), ((PyObject *)__pyx_empty_tuple), NULL); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 106; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":100
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":101
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-static PyObject *__pyx_pf_5_cdec_12SparseVector_29__mul__(PyObject *__pyx_v_x, PyObject *__pyx_v_y) {
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":108
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+  __pyx_t_1 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_SparseVector)), ((PyObject *)__pyx_empty_tuple), NULL); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 115; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":109
+  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":116
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":110
+  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":117
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-static PyObject *__pyx_pw_5_cdec_12SparseVector_32__div__(PyObject *__pyx_v_x, PyObject *__pyx_v_y) {
+static PyObject *__pyx_pw_5_cdec_12SparseVector_34__div__(PyObject *__pyx_v_x, PyObject *__pyx_v_y); /*proto*/
+static PyObject *__pyx_pw_5_cdec_12SparseVector_34__div__(PyObject *__pyx_v_x, PyObject *__pyx_v_y) {
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-/* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":112
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-static PyObject *__pyx_pf_5_cdec_12SparseVector_31__div__(PyObject *__pyx_v_x, PyObject *__pyx_v_y) {
+static PyObject *__pyx_pf_5_cdec_12SparseVector_33__div__(PyObject *__pyx_v_x, PyObject *__pyx_v_y) {
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":115
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-    /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":116
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":117
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":118
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":119
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":70
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  * 
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@@ -4074,7 +4389,7 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_21generator5(__pyx_GeneratorObject
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":71
+  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":77
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-    /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":72
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":73
+  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":79
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@@ -4105,68 +4420,104 @@ static PyObject *__pyx_gb_5_cdec_10Hypergraph_21generator5(__pyx_GeneratorObject
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":76
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-    __pyx_cur_scope->__pyx_v_k = __pyx_t_3;
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-    /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":77
+    /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":83
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+ *             for k in range(hypos.size()):             # <<<<<<<<<<<<<<
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-    /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":78
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- *             yield sentence.decode('utf8')             # <<<<<<<<<<<<<<
- *         del hypos
- * 
+      /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":85
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":79
- *             sentence = GetString(hypos[0][k].words).c_str()
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+  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":87
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  * 
  *     # TODO richer k-best/sample output (feature vectors, trees?)
  */
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@@ -4186,7 +4537,7 @@ static PyObject *__pyx_pw_5_cdec_10Hypergraph_23intersect(PyObject *__pyx_v_self
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+  if (unlikely(!__Pyx_ArgTypeTest(((PyObject *)__pyx_v_lat), __pyx_ptype_5_cdec_Lattice, 1, "lat", 0))) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 91; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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@@ -4196,7 +4547,7 @@ static PyObject *__pyx_pw_5_cdec_10Hypergraph_23intersect(PyObject *__pyx_v_self
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 }
 
-/* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":83
+/* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":91
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":84
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+  __pyx_t_1 = __Pyx_PyBool_FromLong(HG::Intersect((__pyx_v_lat->lattice[0]), __pyx_v_self->hg)); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 92; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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+  __Pyx_RaiseArgtupleInvalid("prune", 0, 0, 2, PyTuple_GET_SIZE(__pyx_args)); {__pyx_filename = __pyx_f[2]; __pyx_lineno = 94; __pyx_clineno = __LINE__; goto __pyx_L3_error;}
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-/* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":86
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":87
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":88
+  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":96
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-    /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":89
+    /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":97
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-    /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":90
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- * 
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":91
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+  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":100
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+ * 
+ */
+  __pyx_t_1 = (__pyx_v_preserve_mask != 0);
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+    /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":101
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+ *         if preserve_mask:
+ *             del preserve_mask             # <<<<<<<<<<<<<<
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-  __pyx_v_self->hg->PruneInsideOutside(__pyx_t_2, __pyx_t_3, __pyx_v_preserve_mask, 0, 1.0, 0);
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   __pyx_r = Py_None; __Pyx_INCREF(Py_None);
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+/* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":103
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":94
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+  if (!(likely(PyString_CheckExact(((PyObject *)__pyx_t_1)))||(PyErr_Format(PyExc_TypeError, "Expected str, got %.200s", Py_TYPE(((PyObject *)__pyx_t_1))->tp_name), 0))) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 104; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":95
+  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":105
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-    /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":99
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+        if (unlikely(__Pyx_ParseOptionalKeywords(__pyx_kwds, __pyx_pyargnames, 0, values, pos_args, "__cinit__") < 0)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 112; __pyx_clineno = __LINE__; goto __pyx_L3_error;}
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+    __pyx_v_name = PyBytes_AsString(values[0]); if (unlikely((!__pyx_v_name) && PyErr_Occurred())) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 112; __pyx_clineno = __LINE__; goto __pyx_L3_error;}
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+  __Pyx_RaiseArgtupleInvalid("__cinit__", 1, 1, 1, PyTuple_GET_SIZE(__pyx_args)); {__pyx_filename = __pyx_f[4]; __pyx_lineno = 112; __pyx_clineno = __LINE__; goto __pyx_L3_error;}
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-/* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":90
+/* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":112
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":91
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  *     def __cinit__(self, char* name):
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- *     def __call__(self, refs):
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@@ -6871,8 +7557,41 @@ static int __pyx_pf_5_cdec_6Scorer___cinit__(struct __pyx_obj_5_cdec_Scorer *__p
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 /* Python wrapper */
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-static PyObject *__pyx_pw_5_cdec_6Scorer_3__call__(PyObject *__pyx_v_self, PyObject *__pyx_args, PyObject *__pyx_kwds) {
+static void __pyx_pw_5_cdec_6Scorer_3__dealloc__(PyObject *__pyx_v_self); /*proto*/
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+
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+ *         del self.name
+ * 
+ */
+
+static void __pyx_pf_5_cdec_6Scorer_2__dealloc__(CYTHON_UNUSED struct __pyx_obj_5_cdec_Scorer *__pyx_v_self) {
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+ *     def __call__(self, refs):
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+  delete __pyx_v_self->name;
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+  __Pyx_RaiseArgtupleInvalid("__call__", 1, 1, 1, PyTuple_GET_SIZE(__pyx_args)); {__pyx_filename = __pyx_f[4]; __pyx_lineno = 118; __pyx_clineno = __LINE__; goto __pyx_L3_error;}
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-/* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":93
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-static PyObject *__pyx_pf_5_cdec_6Scorer_2__call__(struct __pyx_obj_5_cdec_Scorer *__pyx_v_self, PyObject *__pyx_v_refs) {
+static PyObject *__pyx_pf_5_cdec_6Scorer_4__call__(struct __pyx_obj_5_cdec_Scorer *__pyx_v_self, PyObject *__pyx_v_refs) {
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":94
+  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":119
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":95
+  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":120
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-    /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":96
+    /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":121
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+    __pyx_t_1 = PyList_New(1); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 121; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":97
+  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":122
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":100
+  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":125
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+    __pyx_t_5 = -1; __pyx_t_1 = PyObject_GetIter(__pyx_v_refs); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 125; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-          else {__pyx_filename = __pyx_f[4]; __pyx_lineno = 100; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-    /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":101
+    /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":126
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-    /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":102
+    /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":127
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+    __pyx_t_7 = PyObject_GetAttr(__pyx_v_ref, __pyx_n_s__strip); if (unlikely(!__pyx_t_7)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 127; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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+    __pyx_t_8 = PyObject_Call(__pyx_t_7, ((PyObject *)__pyx_empty_tuple), NULL); if (unlikely(!__pyx_t_8)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 127; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-    /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":103
+    /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":128
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-    /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":104
+    /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":129
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":106
+  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":131
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+  __pyx_t_1 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_SegmentEvaluator)), ((PyObject *)__pyx_empty_tuple), NULL); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 131; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":107
+  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":132
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   __pyx_v_evaluator->metric = __pyx_v_metric;
 
-  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":108
+  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":133
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":109
+  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":134
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-  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":110
+  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":135
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-static PyObject *__pyx_pw_5_cdec_6Scorer_5__str__(PyObject *__pyx_v_self) {
+static PyObject *__pyx_pw_5_cdec_6Scorer_7__str__(PyObject *__pyx_v_self); /*proto*/
+static PyObject *__pyx_pw_5_cdec_6Scorer_7__str__(PyObject *__pyx_v_self) {
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+  __pyx_r = __pyx_pf_5_cdec_6Scorer_6__str__(((struct __pyx_obj_5_cdec_Scorer *)__pyx_v_self));
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-/* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":112
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  */
 
-static PyObject *__pyx_pf_5_cdec_6Scorer_4__str__(struct __pyx_obj_5_cdec_Scorer *__pyx_v_self) {
+static PyObject *__pyx_pf_5_cdec_6Scorer_6__str__(struct __pyx_obj_5_cdec_Scorer *__pyx_v_self) {
   PyObject *__pyx_r = NULL;
   __Pyx_RefNannyDeclarations
   PyObject *__pyx_t_1 = NULL;
@@ -7184,7 +7903,7 @@ static PyObject *__pyx_pf_5_cdec_6Scorer_4__str__(struct __pyx_obj_5_cdec_Scorer
   int __pyx_clineno = 0;
   __Pyx_RefNannySetupContext("__str__", 0);
 
-  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":113
+  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":138
  * 
  *     def __str__(self):
  *         return self.name.c_str()             # <<<<<<<<<<<<<<
@@ -7192,7 +7911,7 @@ static PyObject *__pyx_pf_5_cdec_6Scorer_4__str__(struct __pyx_obj_5_cdec_Scorer
  * BLEU = Scorer('IBM_BLEU')
  */
   __Pyx_XDECREF(__pyx_r);
-  __pyx_t_1 = PyBytes_FromString(__pyx_v_self->name->c_str()); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 113; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_t_1 = PyBytes_FromString(__pyx_v_self->name->c_str()); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 138; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_GOTREF(((PyObject *)__pyx_t_1));
   __pyx_r = ((PyObject *)__pyx_t_1);
   __pyx_t_1 = 0;
@@ -8129,7 +8848,7 @@ static PyObject *__pyx_sq_item_5_cdec_DenseVector(PyObject *o, Py_ssize_t i) {
 
 static int __pyx_mp_ass_subscript_5_cdec_DenseVector(PyObject *o, PyObject *i, PyObject *v) {
   if (v) {
-    return __pyx_pw_5_cdec_11DenseVector_3__setitem__(o, i, v);
+    return __pyx_pw_5_cdec_11DenseVector_5__setitem__(o, i, v);
   }
   else {
     PyErr_Format(PyExc_NotImplementedError,
@@ -8139,8 +8858,8 @@ static int __pyx_mp_ass_subscript_5_cdec_DenseVector(PyObject *o, PyObject *i, P
 }
 
 static PyMethodDef __pyx_methods_5_cdec_DenseVector[] = {
-  {__Pyx_NAMESTR("dot"), (PyCFunction)__pyx_pw_5_cdec_11DenseVector_8dot, METH_O, __Pyx_DOCSTR(0)},
-  {__Pyx_NAMESTR("tosparse"), (PyCFunction)__pyx_pw_5_cdec_11DenseVector_10tosparse, METH_NOARGS, __Pyx_DOCSTR(0)},
+  {__Pyx_NAMESTR("dot"), (PyCFunction)__pyx_pw_5_cdec_11DenseVector_10dot, METH_O, __Pyx_DOCSTR(0)},
+  {__Pyx_NAMESTR("tosparse"), (PyCFunction)__pyx_pw_5_cdec_11DenseVector_12tosparse, METH_NOARGS, __Pyx_DOCSTR(0)},
   {0, 0, 0, 0}
 };
 
@@ -8203,7 +8922,7 @@ static PyNumberMethods __pyx_tp_as_number_DenseVector = {
 };
 
 static PySequenceMethods __pyx_tp_as_sequence_DenseVector = {
-  0, /*sq_length*/
+  __pyx_pw_5_cdec_11DenseVector_1__len__, /*sq_length*/
   0, /*sq_concat*/
   0, /*sq_repeat*/
   __pyx_sq_item_5_cdec_DenseVector, /*sq_item*/
@@ -8216,8 +8935,8 @@ static PySequenceMethods __pyx_tp_as_sequence_DenseVector = {
 };
 
 static PyMappingMethods __pyx_tp_as_mapping_DenseVector = {
-  0, /*mp_length*/
-  __pyx_pw_5_cdec_11DenseVector_1__getitem__, /*mp_subscript*/
+  __pyx_pw_5_cdec_11DenseVector_1__len__, /*mp_length*/
+  __pyx_pw_5_cdec_11DenseVector_3__getitem__, /*mp_subscript*/
   __pyx_mp_ass_subscript_5_cdec_DenseVector, /*mp_ass_subscript*/
 };
 
@@ -8272,7 +8991,7 @@ static PyTypeObject __pyx_type_5_cdec_DenseVector = {
   0, /*tp_clear*/
   0, /*tp_richcompare*/
   0, /*tp_weaklistoffset*/
-  __pyx_pw_5_cdec_11DenseVector_5__iter__, /*tp_iter*/
+  __pyx_pw_5_cdec_11DenseVector_7__iter__, /*tp_iter*/
   0, /*tp_iternext*/
   __pyx_methods_5_cdec_DenseVector, /*tp_methods*/
   0, /*tp_members*/
@@ -8305,6 +9024,15 @@ static PyObject *__pyx_tp_new_5_cdec_SparseVector(PyTypeObject *t, PyObject *a,
 }
 
 static void __pyx_tp_dealloc_5_cdec_SparseVector(PyObject *o) {
+  {
+    PyObject *etype, *eval, *etb;
+    PyErr_Fetch(&etype, &eval, &etb);
+    ++Py_REFCNT(o);
+    __pyx_pw_5_cdec_12SparseVector_1__dealloc__(o);
+    if (PyErr_Occurred()) PyErr_WriteUnraisable(o);
+    --Py_REFCNT(o);
+    PyErr_Restore(etype, eval, etb);
+  }
   (*Py_TYPE(o)->tp_free)(o);
 }
 static PyObject *__pyx_sq_item_5_cdec_SparseVector(PyObject *o, Py_ssize_t i) {
@@ -8317,7 +9045,7 @@ static PyObject *__pyx_sq_item_5_cdec_SparseVector(PyObject *o, Py_ssize_t i) {
 
 static int __pyx_mp_ass_subscript_5_cdec_SparseVector(PyObject *o, PyObject *i, PyObject *v) {
   if (v) {
-    return __pyx_pw_5_cdec_12SparseVector_3__setitem__(o, i, v);
+    return __pyx_pw_5_cdec_12SparseVector_7__setitem__(o, i, v);
   }
   else {
     PyErr_Format(PyExc_NotImplementedError,
@@ -8327,17 +9055,17 @@ static int __pyx_mp_ass_subscript_5_cdec_SparseVector(PyObject *o, PyObject *i,
 }
 
 static PyMethodDef __pyx_methods_5_cdec_SparseVector[] = {
-  {__Pyx_NAMESTR("dot"), (PyCFunction)__pyx_pw_5_cdec_12SparseVector_8dot, METH_O, __Pyx_DOCSTR(0)},
-  {__Pyx_NAMESTR("todense"), (PyCFunction)__pyx_pw_5_cdec_12SparseVector_10todense, METH_NOARGS, __Pyx_DOCSTR(0)},
+  {__Pyx_NAMESTR("copy"), (PyCFunction)__pyx_pw_5_cdec_12SparseVector_3copy, METH_NOARGS, __Pyx_DOCSTR(0)},
+  {__Pyx_NAMESTR("dot"), (PyCFunction)__pyx_pw_5_cdec_12SparseVector_12dot, METH_O, __Pyx_DOCSTR(0)},
   {0, 0, 0, 0}
 };
 
 static PyNumberMethods __pyx_tp_as_number_SparseVector = {
-  __pyx_pw_5_cdec_12SparseVector_26__add__, /*nb_add*/
-  __pyx_pw_5_cdec_12SparseVector_28__sub__, /*nb_subtract*/
-  __pyx_pw_5_cdec_12SparseVector_30__mul__, /*nb_multiply*/
+  __pyx_pw_5_cdec_12SparseVector_28__add__, /*nb_add*/
+  __pyx_pw_5_cdec_12SparseVector_30__sub__, /*nb_subtract*/
+  __pyx_pw_5_cdec_12SparseVector_32__mul__, /*nb_multiply*/
   #if PY_MAJOR_VERSION < 3
-  __pyx_pw_5_cdec_12SparseVector_32__div__, /*nb_divide*/
+  __pyx_pw_5_cdec_12SparseVector_34__div__, /*nb_divide*/
   #endif
   0, /*nb_remainder*/
   0, /*nb_divmod*/
@@ -8368,11 +9096,11 @@ static PyNumberMethods __pyx_tp_as_number_SparseVector = {
   #if PY_MAJOR_VERSION < 3
   0, /*nb_hex*/
   #endif
-  __pyx_pw_5_cdec_12SparseVector_18__iadd__, /*nb_inplace_add*/
-  __pyx_pw_5_cdec_12SparseVector_20__isub__, /*nb_inplace_subtract*/
-  __pyx_pw_5_cdec_12SparseVector_22__imul__, /*nb_inplace_multiply*/
+  __pyx_pw_5_cdec_12SparseVector_20__iadd__, /*nb_inplace_add*/
+  __pyx_pw_5_cdec_12SparseVector_22__isub__, /*nb_inplace_subtract*/
+  __pyx_pw_5_cdec_12SparseVector_24__imul__, /*nb_inplace_multiply*/
   #if PY_MAJOR_VERSION < 3
-  __pyx_pw_5_cdec_12SparseVector_24__idiv__, /*nb_inplace_divide*/
+  __pyx_pw_5_cdec_12SparseVector_26__idiv__, /*nb_inplace_divide*/
   #endif
   0, /*nb_inplace_remainder*/
   0, /*nb_inplace_power*/
@@ -8391,21 +9119,21 @@ static PyNumberMethods __pyx_tp_as_number_SparseVector = {
 };
 
 static PySequenceMethods __pyx_tp_as_sequence_SparseVector = {
-  __pyx_pw_5_cdec_12SparseVector_14__len__, /*sq_length*/
+  __pyx_pw_5_cdec_12SparseVector_16__len__, /*sq_length*/
   0, /*sq_concat*/
   0, /*sq_repeat*/
   __pyx_sq_item_5_cdec_SparseVector, /*sq_item*/
   0, /*sq_slice*/
   0, /*sq_ass_item*/
   0, /*sq_ass_slice*/
-  __pyx_pw_5_cdec_12SparseVector_16__contains__, /*sq_contains*/
+  __pyx_pw_5_cdec_12SparseVector_18__contains__, /*sq_contains*/
   0, /*sq_inplace_concat*/
   0, /*sq_inplace_repeat*/
 };
 
 static PyMappingMethods __pyx_tp_as_mapping_SparseVector = {
-  __pyx_pw_5_cdec_12SparseVector_14__len__, /*mp_length*/
-  __pyx_pw_5_cdec_12SparseVector_1__getitem__, /*mp_subscript*/
+  __pyx_pw_5_cdec_12SparseVector_16__len__, /*mp_length*/
+  __pyx_pw_5_cdec_12SparseVector_5__getitem__, /*mp_subscript*/
   __pyx_mp_ass_subscript_5_cdec_SparseVector, /*mp_ass_subscript*/
 };
 
@@ -8458,9 +9186,9 @@ static PyTypeObject __pyx_type_5_cdec_SparseVector = {
   0, /*tp_doc*/
   0, /*tp_traverse*/
   0, /*tp_clear*/
-  __pyx_pw_5_cdec_12SparseVector_12__richcmp__, /*tp_richcompare*/
+  __pyx_pw_5_cdec_12SparseVector_14__richcmp__, /*tp_richcompare*/
   0, /*tp_weaklistoffset*/
-  __pyx_pw_5_cdec_12SparseVector_5__iter__, /*tp_iter*/
+  __pyx_pw_5_cdec_12SparseVector_9__iter__, /*tp_iter*/
   0, /*tp_iternext*/
   __pyx_methods_5_cdec_SparseVector, /*tp_methods*/
   0, /*tp_members*/
@@ -9258,6 +9986,194 @@ static PyTypeObject __pyx_type_5_cdec_SufficientStats = {
   #endif
 };
 
+static PyObject *__pyx_tp_new_5_cdec_CandidateSet(PyTypeObject *t, PyObject *a, PyObject *k) {
+  PyObject *o = (*t->tp_alloc)(t, 0);
+  if (!o) return 0;
+  if (__pyx_pw_5_cdec_12CandidateSet_1__cinit__(o, a, k) < 0) {
+    Py_DECREF(o); o = 0;
+  }
+  return o;
+}
+
+static void __pyx_tp_dealloc_5_cdec_CandidateSet(PyObject *o) {
+  {
+    PyObject *etype, *eval, *etb;
+    PyErr_Fetch(&etype, &eval, &etb);
+    ++Py_REFCNT(o);
+    __pyx_pw_5_cdec_12CandidateSet_3__dealloc__(o);
+    if (PyErr_Occurred()) PyErr_WriteUnraisable(o);
+    --Py_REFCNT(o);
+    PyErr_Restore(etype, eval, etb);
+  }
+  (*Py_TYPE(o)->tp_free)(o);
+}
+static PyObject *__pyx_sq_item_5_cdec_CandidateSet(PyObject *o, Py_ssize_t i) {
+  PyObject *r;
+  PyObject *x = PyInt_FromSsize_t(i); if(!x) return 0;
+  r = Py_TYPE(o)->tp_as_mapping->mp_subscript(o, x);
+  Py_DECREF(x);
+  return r;
+}
+
+static PyMethodDef __pyx_methods_5_cdec_CandidateSet[] = {
+  {__Pyx_NAMESTR("add_kbest"), (PyCFunction)__pyx_pw_5_cdec_12CandidateSet_12add_kbest, METH_VARARGS|METH_KEYWORDS, __Pyx_DOCSTR(0)},
+  {0, 0, 0, 0}
+};
+
+static PyNumberMethods __pyx_tp_as_number_CandidateSet = {
+  0, /*nb_add*/
+  0, /*nb_subtract*/
+  0, /*nb_multiply*/
+  #if PY_MAJOR_VERSION < 3
+  0, /*nb_divide*/
+  #endif
+  0, /*nb_remainder*/
+  0, /*nb_divmod*/
+  0, /*nb_power*/
+  0, /*nb_negative*/
+  0, /*nb_positive*/
+  0, /*nb_absolute*/
+  0, /*nb_nonzero*/
+  0, /*nb_invert*/
+  0, /*nb_lshift*/
+  0, /*nb_rshift*/
+  0, /*nb_and*/
+  0, /*nb_xor*/
+  0, /*nb_or*/
+  #if PY_MAJOR_VERSION < 3
+  0, /*nb_coerce*/
+  #endif
+  0, /*nb_int*/
+  #if PY_MAJOR_VERSION < 3
+  0, /*nb_long*/
+  #else
+  0, /*reserved*/
+  #endif
+  0, /*nb_float*/
+  #if PY_MAJOR_VERSION < 3
+  0, /*nb_oct*/
+  #endif
+  #if PY_MAJOR_VERSION < 3
+  0, /*nb_hex*/
+  #endif
+  0, /*nb_inplace_add*/
+  0, /*nb_inplace_subtract*/
+  0, /*nb_inplace_multiply*/
+  #if PY_MAJOR_VERSION < 3
+  0, /*nb_inplace_divide*/
+  #endif
+  0, /*nb_inplace_remainder*/
+  0, /*nb_inplace_power*/
+  0, /*nb_inplace_lshift*/
+  0, /*nb_inplace_rshift*/
+  0, /*nb_inplace_and*/
+  0, /*nb_inplace_xor*/
+  0, /*nb_inplace_or*/
+  0, /*nb_floor_divide*/
+  0, /*nb_true_divide*/
+  0, /*nb_inplace_floor_divide*/
+  0, /*nb_inplace_true_divide*/
+  #if PY_VERSION_HEX >= 0x02050000
+  0, /*nb_index*/
+  #endif
+};
+
+static PySequenceMethods __pyx_tp_as_sequence_CandidateSet = {
+  __pyx_pw_5_cdec_12CandidateSet_5__len__, /*sq_length*/
+  0, /*sq_concat*/
+  0, /*sq_repeat*/
+  __pyx_sq_item_5_cdec_CandidateSet, /*sq_item*/
+  0, /*sq_slice*/
+  0, /*sq_ass_item*/
+  0, /*sq_ass_slice*/
+  0, /*sq_contains*/
+  0, /*sq_inplace_concat*/
+  0, /*sq_inplace_repeat*/
+};
+
+static PyMappingMethods __pyx_tp_as_mapping_CandidateSet = {
+  __pyx_pw_5_cdec_12CandidateSet_5__len__, /*mp_length*/
+  __pyx_pw_5_cdec_12CandidateSet_7__getitem__, /*mp_subscript*/
+  0, /*mp_ass_subscript*/
+};
+
+static PyBufferProcs __pyx_tp_as_buffer_CandidateSet = {
+  #if PY_MAJOR_VERSION < 3
+  0, /*bf_getreadbuffer*/
+  #endif
+  #if PY_MAJOR_VERSION < 3
+  0, /*bf_getwritebuffer*/
+  #endif
+  #if PY_MAJOR_VERSION < 3
+  0, /*bf_getsegcount*/
+  #endif
+  #if PY_MAJOR_VERSION < 3
+  0, /*bf_getcharbuffer*/
+  #endif
+  #if PY_VERSION_HEX >= 0x02060000
+  0, /*bf_getbuffer*/
+  #endif
+  #if PY_VERSION_HEX >= 0x02060000
+  0, /*bf_releasebuffer*/
+  #endif
+};
+
+static PyTypeObject __pyx_type_5_cdec_CandidateSet = {
+  PyVarObject_HEAD_INIT(0, 0)
+  __Pyx_NAMESTR("_cdec.CandidateSet"), /*tp_name*/
+  sizeof(struct __pyx_obj_5_cdec_CandidateSet), /*tp_basicsize*/
+  0, /*tp_itemsize*/
+  __pyx_tp_dealloc_5_cdec_CandidateSet, /*tp_dealloc*/
+  0, /*tp_print*/
+  0, /*tp_getattr*/
+  0, /*tp_setattr*/
+  #if PY_MAJOR_VERSION < 3
+  0, /*tp_compare*/
+  #else
+  0, /*reserved*/
+  #endif
+  0, /*tp_repr*/
+  &__pyx_tp_as_number_CandidateSet, /*tp_as_number*/
+  &__pyx_tp_as_sequence_CandidateSet, /*tp_as_sequence*/
+  &__pyx_tp_as_mapping_CandidateSet, /*tp_as_mapping*/
+  0, /*tp_hash*/
+  0, /*tp_call*/
+  0, /*tp_str*/
+  0, /*tp_getattro*/
+  0, /*tp_setattro*/
+  &__pyx_tp_as_buffer_CandidateSet, /*tp_as_buffer*/
+  Py_TPFLAGS_DEFAULT|Py_TPFLAGS_CHECKTYPES|Py_TPFLAGS_HAVE_NEWBUFFER|Py_TPFLAGS_BASETYPE, /*tp_flags*/
+  0, /*tp_doc*/
+  0, /*tp_traverse*/
+  0, /*tp_clear*/
+  0, /*tp_richcompare*/
+  0, /*tp_weaklistoffset*/
+  __pyx_pw_5_cdec_12CandidateSet_9__iter__, /*tp_iter*/
+  0, /*tp_iternext*/
+  __pyx_methods_5_cdec_CandidateSet, /*tp_methods*/
+  0, /*tp_members*/
+  0, /*tp_getset*/
+  0, /*tp_base*/
+  0, /*tp_dict*/
+  0, /*tp_descr_get*/
+  0, /*tp_descr_set*/
+  0, /*tp_dictoffset*/
+  0, /*tp_init*/
+  0, /*tp_alloc*/
+  __pyx_tp_new_5_cdec_CandidateSet, /*tp_new*/
+  0, /*tp_free*/
+  0, /*tp_is_gc*/
+  0, /*tp_bases*/
+  0, /*tp_mro*/
+  0, /*tp_cache*/
+  0, /*tp_subclasses*/
+  0, /*tp_weaklist*/
+  0, /*tp_del*/
+  #if PY_VERSION_HEX >= 0x02060000
+  0, /*tp_version_tag*/
+  #endif
+};
+
 static PyObject *__pyx_tp_new_5_cdec_SegmentEvaluator(PyTypeObject *t, PyObject *a, PyObject *k) {
   PyObject *o = (*t->tp_alloc)(t, 0);
   if (!o) return 0;
@@ -9279,7 +10195,7 @@ static void __pyx_tp_dealloc_5_cdec_SegmentEvaluator(PyObject *o) {
 
 static PyMethodDef __pyx_methods_5_cdec_SegmentEvaluator[] = {
   {__Pyx_NAMESTR("evaluate"), (PyCFunction)__pyx_pw_5_cdec_16SegmentEvaluator_3evaluate, METH_O, __Pyx_DOCSTR(0)},
-  {__Pyx_NAMESTR("candidate_set"), (PyCFunction)__pyx_pw_5_cdec_16SegmentEvaluator_5candidate_set, METH_VARARGS|METH_KEYWORDS, __Pyx_DOCSTR(0)},
+  {__Pyx_NAMESTR("candidate_set"), (PyCFunction)__pyx_pw_5_cdec_16SegmentEvaluator_5candidate_set, METH_NOARGS, __Pyx_DOCSTR(0)},
   {0, 0, 0, 0}
 };
 
@@ -9447,6 +10363,15 @@ static PyObject *__pyx_tp_new_5_cdec_Scorer(PyTypeObject *t, PyObject *a, PyObje
 }
 
 static void __pyx_tp_dealloc_5_cdec_Scorer(PyObject *o) {
+  {
+    PyObject *etype, *eval, *etb;
+    PyErr_Fetch(&etype, &eval, &etb);
+    ++Py_REFCNT(o);
+    __pyx_pw_5_cdec_6Scorer_3__dealloc__(o);
+    if (PyErr_Occurred()) PyErr_WriteUnraisable(o);
+    --Py_REFCNT(o);
+    PyErr_Restore(etype, eval, etb);
+  }
   (*Py_TYPE(o)->tp_free)(o);
 }
 
@@ -9571,8 +10496,8 @@ static PyTypeObject __pyx_type_5_cdec_Scorer = {
   &__pyx_tp_as_sequence_Scorer, /*tp_as_sequence*/
   &__pyx_tp_as_mapping_Scorer, /*tp_as_mapping*/
   0, /*tp_hash*/
-  __pyx_pw_5_cdec_6Scorer_3__call__, /*tp_call*/
-  __pyx_pw_5_cdec_6Scorer_5__str__, /*tp_str*/
+  __pyx_pw_5_cdec_6Scorer_5__call__, /*tp_call*/
+  __pyx_pw_5_cdec_6Scorer_7__str__, /*tp_str*/
   0, /*tp_getattro*/
   0, /*tp_setattro*/
   &__pyx_tp_as_buffer_Scorer, /*tp_as_buffer*/
@@ -10027,14 +10952,12 @@ static PyObject *__pyx_tp_new_5_cdec___pyx_scope_struct_1___iter__(PyTypeObject
   PyObject *o = (*t->tp_alloc)(t, 0);
   if (!o) return 0;
   p = ((struct __pyx_obj_5_cdec___pyx_scope_struct_1___iter__ *)o);
-  p->__pyx_v_fname = 0;
   p->__pyx_v_self = 0;
   return o;
 }
 
 static void __pyx_tp_dealloc_5_cdec___pyx_scope_struct_1___iter__(PyObject *o) {
   struct __pyx_obj_5_cdec___pyx_scope_struct_1___iter__ *p = (struct __pyx_obj_5_cdec___pyx_scope_struct_1___iter__ *)o;
-  Py_XDECREF(((PyObject *)p->__pyx_v_fname));
   Py_XDECREF(((PyObject *)p->__pyx_v_self));
   (*Py_TYPE(o)->tp_free)(o);
 }
@@ -10042,9 +10965,6 @@ static void __pyx_tp_dealloc_5_cdec___pyx_scope_struct_1___iter__(PyObject *o) {
 static int __pyx_tp_traverse_5_cdec___pyx_scope_struct_1___iter__(PyObject *o, visitproc v, void *a) {
   int e;
   struct __pyx_obj_5_cdec___pyx_scope_struct_1___iter__ *p = (struct __pyx_obj_5_cdec___pyx_scope_struct_1___iter__ *)o;
-  if (p->__pyx_v_fname) {
-    e = (*v)(p->__pyx_v_fname, a); if (e) return e;
-  }
   if (p->__pyx_v_self) {
     e = (*v)(((PyObject*)p->__pyx_v_self), a); if (e) return e;
   }
@@ -10054,9 +10974,6 @@ static int __pyx_tp_traverse_5_cdec___pyx_scope_struct_1___iter__(PyObject *o, v
 static int __pyx_tp_clear_5_cdec___pyx_scope_struct_1___iter__(PyObject *o) {
   struct __pyx_obj_5_cdec___pyx_scope_struct_1___iter__ *p = (struct __pyx_obj_5_cdec___pyx_scope_struct_1___iter__ *)o;
   PyObject* tmp;
-  tmp = ((PyObject*)p->__pyx_v_fname);
-  p->__pyx_v_fname = ((PyObject*)Py_None); Py_INCREF(Py_None);
-  Py_XDECREF(tmp);
   tmp = ((PyObject*)p->__pyx_v_self);
   p->__pyx_v_self = ((struct __pyx_obj_5_cdec_SparseVector *)Py_None); Py_INCREF(Py_None);
   Py_XDECREF(tmp);
@@ -11439,60 +12356,44 @@ static PyTypeObject __pyx_type_5_cdec___pyx_scope_struct_7___iter__ = {
   #endif
 };
 
-static PyObject *__pyx_tp_new_5_cdec___pyx_scope_struct_8_candidate_set(PyTypeObject *t, PyObject *a, PyObject *k) {
-  struct __pyx_obj_5_cdec___pyx_scope_struct_8_candidate_set *p;
+static PyObject *__pyx_tp_new_5_cdec___pyx_scope_struct_8___iter__(PyTypeObject *t, PyObject *a, PyObject *k) {
+  struct __pyx_obj_5_cdec___pyx_scope_struct_8___iter__ *p;
   PyObject *o = (*t->tp_alloc)(t, 0);
   if (!o) return 0;
-  p = ((struct __pyx_obj_5_cdec___pyx_scope_struct_8_candidate_set *)o);
-  p->__pyx_v_candidate = 0;
-  p->__pyx_v_hypergraph = 0;
+  p = ((struct __pyx_obj_5_cdec___pyx_scope_struct_8___iter__ *)o);
   p->__pyx_v_self = 0;
   return o;
 }
 
-static void __pyx_tp_dealloc_5_cdec___pyx_scope_struct_8_candidate_set(PyObject *o) {
-  struct __pyx_obj_5_cdec___pyx_scope_struct_8_candidate_set *p = (struct __pyx_obj_5_cdec___pyx_scope_struct_8_candidate_set *)o;
-  Py_XDECREF(((PyObject *)p->__pyx_v_candidate));
-  Py_XDECREF(((PyObject *)p->__pyx_v_hypergraph));
+static void __pyx_tp_dealloc_5_cdec___pyx_scope_struct_8___iter__(PyObject *o) {
+  struct __pyx_obj_5_cdec___pyx_scope_struct_8___iter__ *p = (struct __pyx_obj_5_cdec___pyx_scope_struct_8___iter__ *)o;
   Py_XDECREF(((PyObject *)p->__pyx_v_self));
   (*Py_TYPE(o)->tp_free)(o);
 }
 
-static int __pyx_tp_traverse_5_cdec___pyx_scope_struct_8_candidate_set(PyObject *o, visitproc v, void *a) {
+static int __pyx_tp_traverse_5_cdec___pyx_scope_struct_8___iter__(PyObject *o, visitproc v, void *a) {
   int e;
-  struct __pyx_obj_5_cdec___pyx_scope_struct_8_candidate_set *p = (struct __pyx_obj_5_cdec___pyx_scope_struct_8_candidate_set *)o;
-  if (p->__pyx_v_candidate) {
-    e = (*v)(((PyObject*)p->__pyx_v_candidate), a); if (e) return e;
-  }
-  if (p->__pyx_v_hypergraph) {
-    e = (*v)(((PyObject*)p->__pyx_v_hypergraph), a); if (e) return e;
-  }
+  struct __pyx_obj_5_cdec___pyx_scope_struct_8___iter__ *p = (struct __pyx_obj_5_cdec___pyx_scope_struct_8___iter__ *)o;
   if (p->__pyx_v_self) {
     e = (*v)(((PyObject*)p->__pyx_v_self), a); if (e) return e;
   }
   return 0;
 }
 
-static int __pyx_tp_clear_5_cdec___pyx_scope_struct_8_candidate_set(PyObject *o) {
-  struct __pyx_obj_5_cdec___pyx_scope_struct_8_candidate_set *p = (struct __pyx_obj_5_cdec___pyx_scope_struct_8_candidate_set *)o;
+static int __pyx_tp_clear_5_cdec___pyx_scope_struct_8___iter__(PyObject *o) {
+  struct __pyx_obj_5_cdec___pyx_scope_struct_8___iter__ *p = (struct __pyx_obj_5_cdec___pyx_scope_struct_8___iter__ *)o;
   PyObject* tmp;
-  tmp = ((PyObject*)p->__pyx_v_candidate);
-  p->__pyx_v_candidate = ((struct __pyx_obj_5_cdec_Candidate *)Py_None); Py_INCREF(Py_None);
-  Py_XDECREF(tmp);
-  tmp = ((PyObject*)p->__pyx_v_hypergraph);
-  p->__pyx_v_hypergraph = ((struct __pyx_obj_5_cdec_Hypergraph *)Py_None); Py_INCREF(Py_None);
-  Py_XDECREF(tmp);
   tmp = ((PyObject*)p->__pyx_v_self);
-  p->__pyx_v_self = ((struct __pyx_obj_5_cdec_SegmentEvaluator *)Py_None); Py_INCREF(Py_None);
+  p->__pyx_v_self = ((struct __pyx_obj_5_cdec_CandidateSet *)Py_None); Py_INCREF(Py_None);
   Py_XDECREF(tmp);
   return 0;
 }
 
-static PyMethodDef __pyx_methods_5_cdec___pyx_scope_struct_8_candidate_set[] = {
+static PyMethodDef __pyx_methods_5_cdec___pyx_scope_struct_8___iter__[] = {
   {0, 0, 0, 0}
 };
 
-static PyNumberMethods __pyx_tp_as_number___pyx_scope_struct_8_candidate_set = {
+static PyNumberMethods __pyx_tp_as_number___pyx_scope_struct_8___iter__ = {
   0, /*nb_add*/
   0, /*nb_subtract*/
   0, /*nb_multiply*/
@@ -11550,7 +12451,7 @@ static PyNumberMethods __pyx_tp_as_number___pyx_scope_struct_8_candidate_set = {
   #endif
 };
 
-static PySequenceMethods __pyx_tp_as_sequence___pyx_scope_struct_8_candidate_set = {
+static PySequenceMethods __pyx_tp_as_sequence___pyx_scope_struct_8___iter__ = {
   0, /*sq_length*/
   0, /*sq_concat*/
   0, /*sq_repeat*/
@@ -11563,13 +12464,13 @@ static PySequenceMethods __pyx_tp_as_sequence___pyx_scope_struct_8_candidate_set
   0, /*sq_inplace_repeat*/
 };
 
-static PyMappingMethods __pyx_tp_as_mapping___pyx_scope_struct_8_candidate_set = {
+static PyMappingMethods __pyx_tp_as_mapping___pyx_scope_struct_8___iter__ = {
   0, /*mp_length*/
   0, /*mp_subscript*/
   0, /*mp_ass_subscript*/
 };
 
-static PyBufferProcs __pyx_tp_as_buffer___pyx_scope_struct_8_candidate_set = {
+static PyBufferProcs __pyx_tp_as_buffer___pyx_scope_struct_8___iter__ = {
   #if PY_MAJOR_VERSION < 3
   0, /*bf_getreadbuffer*/
   #endif
@@ -11590,12 +12491,12 @@ static PyBufferProcs __pyx_tp_as_buffer___pyx_scope_struct_8_candidate_set = {
   #endif
 };
 
-static PyTypeObject __pyx_type_5_cdec___pyx_scope_struct_8_candidate_set = {
+static PyTypeObject __pyx_type_5_cdec___pyx_scope_struct_8___iter__ = {
   PyVarObject_HEAD_INIT(0, 0)
-  __Pyx_NAMESTR("_cdec.__pyx_scope_struct_8_candidate_set"), /*tp_name*/
-  sizeof(struct __pyx_obj_5_cdec___pyx_scope_struct_8_candidate_set), /*tp_basicsize*/
+  __Pyx_NAMESTR("_cdec.__pyx_scope_struct_8___iter__"), /*tp_name*/
+  sizeof(struct __pyx_obj_5_cdec___pyx_scope_struct_8___iter__), /*tp_basicsize*/
   0, /*tp_itemsize*/
-  __pyx_tp_dealloc_5_cdec___pyx_scope_struct_8_candidate_set, /*tp_dealloc*/
+  __pyx_tp_dealloc_5_cdec___pyx_scope_struct_8___iter__, /*tp_dealloc*/
   0, /*tp_print*/
   0, /*tp_getattr*/
   0, /*tp_setattr*/
@@ -11605,24 +12506,24 @@ static PyTypeObject __pyx_type_5_cdec___pyx_scope_struct_8_candidate_set = {
   0, /*reserved*/
   #endif
   0, /*tp_repr*/
-  &__pyx_tp_as_number___pyx_scope_struct_8_candidate_set, /*tp_as_number*/
-  &__pyx_tp_as_sequence___pyx_scope_struct_8_candidate_set, /*tp_as_sequence*/
-  &__pyx_tp_as_mapping___pyx_scope_struct_8_candidate_set, /*tp_as_mapping*/
+  &__pyx_tp_as_number___pyx_scope_struct_8___iter__, /*tp_as_number*/
+  &__pyx_tp_as_sequence___pyx_scope_struct_8___iter__, /*tp_as_sequence*/
+  &__pyx_tp_as_mapping___pyx_scope_struct_8___iter__, /*tp_as_mapping*/
   0, /*tp_hash*/
   0, /*tp_call*/
   0, /*tp_str*/
   0, /*tp_getattro*/
   0, /*tp_setattro*/
-  &__pyx_tp_as_buffer___pyx_scope_struct_8_candidate_set, /*tp_as_buffer*/
+  &__pyx_tp_as_buffer___pyx_scope_struct_8___iter__, /*tp_as_buffer*/
   Py_TPFLAGS_DEFAULT|Py_TPFLAGS_CHECKTYPES|Py_TPFLAGS_HAVE_NEWBUFFER|Py_TPFLAGS_HAVE_GC, /*tp_flags*/
   0, /*tp_doc*/
-  __pyx_tp_traverse_5_cdec___pyx_scope_struct_8_candidate_set, /*tp_traverse*/
-  __pyx_tp_clear_5_cdec___pyx_scope_struct_8_candidate_set, /*tp_clear*/
+  __pyx_tp_traverse_5_cdec___pyx_scope_struct_8___iter__, /*tp_traverse*/
+  __pyx_tp_clear_5_cdec___pyx_scope_struct_8___iter__, /*tp_clear*/
   0, /*tp_richcompare*/
   0, /*tp_weaklistoffset*/
   0, /*tp_iter*/
   0, /*tp_iternext*/
-  __pyx_methods_5_cdec___pyx_scope_struct_8_candidate_set, /*tp_methods*/
+  __pyx_methods_5_cdec___pyx_scope_struct_8___iter__, /*tp_methods*/
   0, /*tp_members*/
   0, /*tp_getset*/
   0, /*tp_base*/
@@ -11632,7 +12533,7 @@ static PyTypeObject __pyx_type_5_cdec___pyx_scope_struct_8_candidate_set = {
   0, /*tp_dictoffset*/
   0, /*tp_init*/
   0, /*tp_alloc*/
-  __pyx_tp_new_5_cdec___pyx_scope_struct_8_candidate_set, /*tp_new*/
+  __pyx_tp_new_5_cdec___pyx_scope_struct_8___iter__, /*tp_new*/
   0, /*tp_free*/
   0, /*tp_is_gc*/
   0, /*tp_bases*/
@@ -11696,6 +12597,7 @@ static __Pyx_StringTabEntry __pyx_string_tab[] = {
   {&__pyx_n_s__encoding, __pyx_k__encoding, sizeof(__pyx_k__encoding), 0, 0, 1, 1},
   {&__pyx_n_s__enumerate, __pyx_k__enumerate, sizeof(__pyx_k__enumerate), 0, 0, 1, 1},
   {&__pyx_n_s__eval, __pyx_k__eval, sizeof(__pyx_k__eval), 0, 0, 1, 1},
+  {&__pyx_n_s__evaluator, __pyx_k__evaluator, sizeof(__pyx_k__evaluator), 0, 0, 1, 1},
   {&__pyx_n_s__grammar, __pyx_k__grammar, sizeof(__pyx_k__grammar), 0, 0, 1, 1},
   {&__pyx_n_s__hypergraph, __pyx_k__hypergraph, sizeof(__pyx_k__hypergraph), 0, 0, 1, 1},
   {&__pyx_n_s__inp, __pyx_k__inp, sizeof(__pyx_k__inp), 0, 0, 1, 1},
@@ -11714,11 +12616,11 @@ static __Pyx_StringTabEntry __pyx_string_tab[] = {
 };
 static int __Pyx_InitCachedBuiltins(void) {
   __pyx_builtin_Exception = __Pyx_GetName(__pyx_b, __pyx_n_s__Exception); if (!__pyx_builtin_Exception) {__pyx_filename = __pyx_f[0]; __pyx_lineno = 13; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
-  __pyx_builtin_KeyError = __Pyx_GetName(__pyx_b, __pyx_n_s__KeyError); if (!__pyx_builtin_KeyError) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 10; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
-  __pyx_builtin_range = __Pyx_GetName(__pyx_b, __pyx_n_s__range); if (!__pyx_builtin_range) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 20; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
-  __pyx_builtin_TypeError = __Pyx_GetName(__pyx_b, __pyx_n_s__TypeError); if (!__pyx_builtin_TypeError) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 56; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
-  __pyx_builtin_NotImplemented = __Pyx_GetName(__pyx_b, __pyx_n_s__NotImplemented); if (!__pyx_builtin_NotImplemented) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 69; __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[2]; __pyx_lineno = 95; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_builtin_KeyError = __Pyx_GetName(__pyx_b, __pyx_n_s__KeyError); if (!__pyx_builtin_KeyError) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 13; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_builtin_range = __Pyx_GetName(__pyx_b, __pyx_n_s__range); if (!__pyx_builtin_range) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 24; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_builtin_TypeError = __Pyx_GetName(__pyx_b, __pyx_n_s__TypeError); if (!__pyx_builtin_TypeError) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 69; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_builtin_NotImplemented = __Pyx_GetName(__pyx_b, __pyx_n_s__NotImplemented); if (!__pyx_builtin_NotImplemented) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 76; __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[2]; __pyx_lineno = 105; __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[3]; __pyx_lineno = 9; __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[3]; __pyx_lineno = 21; __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 = 31; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
@@ -11731,14 +12633,14 @@ static int __Pyx_InitCachedConstants(void) {
   __Pyx_RefNannyDeclarations
   __Pyx_RefNannySetupContext("__Pyx_InitCachedConstants", 0);
 
-  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":69
+  /* "/Users/vchahun/Sandbox/cdec/python/src/vectors.pxi":76
  *         elif op == 3: # !=
  *             return not (x == y)
  *         raise NotImplemented('comparison not implemented for SparseVector')             # <<<<<<<<<<<<<<
  * 
  *     def __len__(self):
  */
-  __pyx_k_tuple_3 = PyTuple_New(1); if (unlikely(!__pyx_k_tuple_3)) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 69; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_k_tuple_3 = PyTuple_New(1); if (unlikely(!__pyx_k_tuple_3)) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 76; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_GOTREF(__pyx_k_tuple_3);
   __Pyx_INCREF(((PyObject *)__pyx_kp_s_2));
   PyTuple_SET_ITEM(__pyx_k_tuple_3, 0, ((PyObject *)__pyx_kp_s_2));
@@ -11787,42 +12689,42 @@ static int __Pyx_InitCachedConstants(void) {
   __Pyx_GIVEREF(((PyObject *)__pyx_n_s__utf8));
   __Pyx_GIVEREF(((PyObject *)__pyx_k_tuple_6));
 
-  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":41
- *             if not derivation: break
- *             sentence = GetString(derivation._yield).c_str()
- *             yield sentence.decode('utf8')             # <<<<<<<<<<<<<<
- *         del derivations
- * 
+  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":42
+ *                 if not derivation: break
+ *                 sentence = GetString(derivation._yield).c_str()
+ *                 yield sentence.decode('utf8')             # <<<<<<<<<<<<<<
+ *         finally:
+ *             del derivations
  */
-  __pyx_k_tuple_7 = PyTuple_New(1); if (unlikely(!__pyx_k_tuple_7)) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 41; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_k_tuple_7 = PyTuple_New(1); if (unlikely(!__pyx_k_tuple_7)) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 42; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_GOTREF(__pyx_k_tuple_7);
   __Pyx_INCREF(((PyObject *)__pyx_n_s__utf8));
   PyTuple_SET_ITEM(__pyx_k_tuple_7, 0, ((PyObject *)__pyx_n_s__utf8));
   __Pyx_GIVEREF(((PyObject *)__pyx_n_s__utf8));
   __Pyx_GIVEREF(((PyObject *)__pyx_k_tuple_7));
 
-  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":53
- *             if not derivation: break
- *             tree = GetString(derivation._yield).c_str()
- *             yield tree.decode('utf8')             # <<<<<<<<<<<<<<
- *         del derivations
- * 
+  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":56
+ *                 if not derivation: break
+ *                 tree = GetString(derivation._yield).c_str()
+ *                 yield tree.decode('utf8')             # <<<<<<<<<<<<<<
+ *         finally:
+ *             del derivations
  */
-  __pyx_k_tuple_8 = PyTuple_New(1); if (unlikely(!__pyx_k_tuple_8)) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 53; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_k_tuple_8 = PyTuple_New(1); if (unlikely(!__pyx_k_tuple_8)) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 56; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_GOTREF(__pyx_k_tuple_8);
   __Pyx_INCREF(((PyObject *)__pyx_n_s__utf8));
   PyTuple_SET_ITEM(__pyx_k_tuple_8, 0, ((PyObject *)__pyx_n_s__utf8));
   __Pyx_GIVEREF(((PyObject *)__pyx_n_s__utf8));
   __Pyx_GIVEREF(((PyObject *)__pyx_k_tuple_8));
 
-  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":78
- *         for k in range(hypos.size()):
- *             sentence = GetString(hypos[0][k].words).c_str()
- *             yield sentence.decode('utf8')             # <<<<<<<<<<<<<<
- *         del hypos
- * 
+  /* "/Users/vchahun/Sandbox/cdec/python/src/hypergraph.pxi":85
+ *             for k in range(hypos.size()):
+ *                 sentence = GetString(hypos[0][k].words).c_str()
+ *                 yield sentence.decode('utf8')             # <<<<<<<<<<<<<<
+ *         finally:
+ *             del hypos
  */
-  __pyx_k_tuple_9 = PyTuple_New(1); if (unlikely(!__pyx_k_tuple_9)) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 78; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_k_tuple_9 = PyTuple_New(1); if (unlikely(!__pyx_k_tuple_9)) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 85; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_GOTREF(__pyx_k_tuple_9);
   __Pyx_INCREF(((PyObject *)__pyx_n_s__utf8));
   PyTuple_SET_ITEM(__pyx_k_tuple_9, 0, ((PyObject *)__pyx_n_s__utf8));
@@ -11947,25 +12849,25 @@ static int __Pyx_InitCachedConstants(void) {
   __Pyx_GIVEREF(((PyObject *)__pyx_n_s__utf8));
   __Pyx_GIVEREF(((PyObject *)__pyx_k_tuple_22));
 
-  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":115
+  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":140
  *         return self.name.c_str()
  * 
  * BLEU = Scorer('IBM_BLEU')             # <<<<<<<<<<<<<<
  * TER = Scorer('TER')
  */
-  __pyx_k_tuple_24 = PyTuple_New(1); if (unlikely(!__pyx_k_tuple_24)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 115; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_k_tuple_24 = PyTuple_New(1); if (unlikely(!__pyx_k_tuple_24)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 140; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_GOTREF(__pyx_k_tuple_24);
   __Pyx_INCREF(((PyObject *)__pyx_n_s__IBM_BLEU));
   PyTuple_SET_ITEM(__pyx_k_tuple_24, 0, ((PyObject *)__pyx_n_s__IBM_BLEU));
   __Pyx_GIVEREF(((PyObject *)__pyx_n_s__IBM_BLEU));
   __Pyx_GIVEREF(((PyObject *)__pyx_k_tuple_24));
 
-  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":116
+  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":141
  * 
  * BLEU = Scorer('IBM_BLEU')
  * TER = Scorer('TER')             # <<<<<<<<<<<<<<
  */
-  __pyx_k_tuple_25 = PyTuple_New(1); if (unlikely(!__pyx_k_tuple_25)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 116; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_k_tuple_25 = PyTuple_New(1); if (unlikely(!__pyx_k_tuple_25)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 141; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_GOTREF(__pyx_k_tuple_25);
   __Pyx_INCREF(((PyObject *)__pyx_n_s__TER));
   PyTuple_SET_ITEM(__pyx_k_tuple_25, 0, ((PyObject *)__pyx_n_s__TER));
@@ -12057,8 +12959,8 @@ PyMODINIT_FUNC PyInit__cdec(void)
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   if (__Pyx_SetAttrString(__pyx_m, "DenseVector", (PyObject *)&__pyx_type_5_cdec_DenseVector) < 0) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 3; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec_DenseVector = &__pyx_type_5_cdec_DenseVector;
-  if (PyType_Ready(&__pyx_type_5_cdec_SparseVector) < 0) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 32; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
-  if (__Pyx_SetAttrString(__pyx_m, "SparseVector", (PyObject *)&__pyx_type_5_cdec_SparseVector) < 0) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 32; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec_SparseVector) < 0) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 36; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (__Pyx_SetAttrString(__pyx_m, "SparseVector", (PyObject *)&__pyx_type_5_cdec_SparseVector) < 0) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 36; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec_SparseVector = &__pyx_type_5_cdec_SparseVector;
   if (PyType_Ready(&__pyx_type_5_cdec_Hypergraph) < 0) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 4; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   if (__Pyx_SetAttrString(__pyx_m, "Hypergraph", (PyObject *)&__pyx_type_5_cdec_Hypergraph) < 0) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 4; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
@@ -12072,57 +12974,60 @@ PyMODINIT_FUNC PyInit__cdec(void)
   if (PyType_Ready(&__pyx_type_5_cdec_SufficientStats) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 27; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   if (__Pyx_SetAttrString(__pyx_m, "SufficientStats", (PyObject *)&__pyx_type_5_cdec_SufficientStats) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 27; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec_SufficientStats = &__pyx_type_5_cdec_SufficientStats;
-  if (PyType_Ready(&__pyx_type_5_cdec_SegmentEvaluator) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 59; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
-  if (__Pyx_SetAttrString(__pyx_m, "SegmentEvaluator", (PyObject *)&__pyx_type_5_cdec_SegmentEvaluator) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 59; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec_CandidateSet) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 59; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (__Pyx_SetAttrString(__pyx_m, "CandidateSet", (PyObject *)&__pyx_type_5_cdec_CandidateSet) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 59; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_ptype_5_cdec_CandidateSet = &__pyx_type_5_cdec_CandidateSet;
+  if (PyType_Ready(&__pyx_type_5_cdec_SegmentEvaluator) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 90; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (__Pyx_SetAttrString(__pyx_m, "SegmentEvaluator", (PyObject *)&__pyx_type_5_cdec_SegmentEvaluator) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 90; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec_SegmentEvaluator = &__pyx_type_5_cdec_SegmentEvaluator;
-  if (PyType_Ready(&__pyx_type_5_cdec_Scorer) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 87; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
-  if (__Pyx_SetAttrString(__pyx_m, "Scorer", (PyObject *)&__pyx_type_5_cdec_Scorer) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 87; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec_Scorer) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 109; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (__Pyx_SetAttrString(__pyx_m, "Scorer", (PyObject *)&__pyx_type_5_cdec_Scorer) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 109; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec_Scorer = &__pyx_type_5_cdec_Scorer;
   if (PyType_Ready(&__pyx_type_5_cdec_Decoder) < 0) {__pyx_filename = __pyx_f[0]; __pyx_lineno = 15; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   if (__Pyx_SetAttrString(__pyx_m, "Decoder", (PyObject *)&__pyx_type_5_cdec_Decoder) < 0) {__pyx_filename = __pyx_f[0]; __pyx_lineno = 15; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec_Decoder = &__pyx_type_5_cdec_Decoder;
-  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct____iter__) < 0) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 18; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct____iter__) < 0) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 22; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct____iter__ = &__pyx_type_5_cdec___pyx_scope_struct____iter__;
-  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_1___iter__) < 0) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 43; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_1___iter__) < 0) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 55; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_1___iter__ = &__pyx_type_5_cdec___pyx_scope_struct_1___iter__;
   if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_2_kbest) < 0) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 32; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_2_kbest = &__pyx_type_5_cdec___pyx_scope_struct_2_kbest;
-  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_3_kbest_tree) < 0) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 44; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_3_kbest_tree) < 0) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 46; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_3_kbest_tree = &__pyx_type_5_cdec___pyx_scope_struct_3_kbest_tree;
-  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_4_kbest_features) < 0) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 56; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_4_kbest_features) < 0) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 60; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_4_kbest_features = &__pyx_type_5_cdec___pyx_scope_struct_4_kbest_features;
-  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_5_sample) < 0) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 69; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_5_sample) < 0) {__pyx_filename = __pyx_f[2]; __pyx_lineno = 75; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_5_sample = &__pyx_type_5_cdec___pyx_scope_struct_5_sample;
   if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_6___iter__) < 0) {__pyx_filename = __pyx_f[3]; __pyx_lineno = 50; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __pyx_ptype_5_cdec___pyx_scope_struct_6___iter__ = &__pyx_type_5_cdec___pyx_scope_struct_6___iter__;
   if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_7___iter__) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 45; __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_candidate_set) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 75; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
-  __pyx_ptype_5_cdec___pyx_scope_struct_8_candidate_set = &__pyx_type_5_cdec___pyx_scope_struct_8_candidate_set;
+  if (PyType_Ready(&__pyx_type_5_cdec___pyx_scope_struct_8___iter__) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 82; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_ptype_5_cdec___pyx_scope_struct_8___iter__ = &__pyx_type_5_cdec___pyx_scope_struct_8___iter__;
   /*--- Type import code ---*/
   /*--- Variable import code ---*/
   /*--- Function import code ---*/
   /*--- Execution code ---*/
 
-  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":115
+  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":140
  *         return self.name.c_str()
  * 
  * BLEU = Scorer('IBM_BLEU')             # <<<<<<<<<<<<<<
  * TER = Scorer('TER')
  */
-  __pyx_t_1 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_Scorer)), ((PyObject *)__pyx_k_tuple_24), NULL); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 115; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_t_1 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_Scorer)), ((PyObject *)__pyx_k_tuple_24), NULL); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 140; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_GOTREF(__pyx_t_1);
-  if (PyObject_SetAttr(__pyx_m, __pyx_n_s__BLEU, __pyx_t_1) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 115; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyObject_SetAttr(__pyx_m, __pyx_n_s__BLEU, __pyx_t_1) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 140; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_DECREF(__pyx_t_1); __pyx_t_1 = 0;
 
-  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":116
+  /* "/Users/vchahun/Sandbox/cdec/python/src/mteval.pxi":141
  * 
  * BLEU = Scorer('IBM_BLEU')
  * TER = Scorer('TER')             # <<<<<<<<<<<<<<
  */
-  __pyx_t_1 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_Scorer)), ((PyObject *)__pyx_k_tuple_25), NULL); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 116; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  __pyx_t_1 = PyObject_Call(((PyObject *)((PyObject*)__pyx_ptype_5_cdec_Scorer)), ((PyObject *)__pyx_k_tuple_25), NULL); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 141; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_GOTREF(__pyx_t_1);
-  if (PyObject_SetAttr(__pyx_m, __pyx_n_s__TER, __pyx_t_1) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 116; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
+  if (PyObject_SetAttr(__pyx_m, __pyx_n_s__TER, __pyx_t_1) < 0) {__pyx_filename = __pyx_f[4]; __pyx_lineno = 141; __pyx_clineno = __LINE__; goto __pyx_L1_error;}
   __Pyx_DECREF(__pyx_t_1); __pyx_t_1 = 0;
 
   /* "_cdec.pyx":11
diff --git a/python/src/hypergraph.pxi b/python/src/hypergraph.pxi
index ce78b729..9d09722e 100644
--- a/python/src/hypergraph.pxi
+++ b/python/src/hypergraph.pxi
@@ -32,39 +32,45 @@ cdef class Hypergraph:
     def kbest(self, size):
         cdef kb.KBestDerivations[vector[WordID], kb.ESentenceTraversal]* derivations = new kb.KBestDerivations[vector[WordID], kb.ESentenceTraversal](self.hg[0], size)
         cdef kb.KBestDerivations[vector[WordID], kb.ESentenceTraversal].Derivation* derivation
-        cdef str sentence
+        cdef bytes sentence
         cdef unsigned k
-        for k in range(size):
-            derivation = derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
-            if not derivation: break
-            sentence = GetString(derivation._yield).c_str()
-            yield sentence.decode('utf8')
-        del derivations
+        try:
+            for k in range(size):
+                derivation = derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
+                if not derivation: break
+                sentence = GetString(derivation._yield).c_str()
+                yield sentence.decode('utf8')
+        finally:
+            del derivations
 
     def kbest_tree(self, size):
         cdef kb.KBestDerivations[vector[WordID], kb.ETreeTraversal]* derivations = new kb.KBestDerivations[vector[WordID], kb.ETreeTraversal](self.hg[0], size)
         cdef kb.KBestDerivations[vector[WordID], kb.ETreeTraversal].Derivation* derivation
         cdef str tree
         cdef unsigned k
-        for k in range(size):
-            derivation = derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
-            if not derivation: break
-            tree = GetString(derivation._yield).c_str()
-            yield tree.decode('utf8')
-        del derivations
+        try:
+            for k in range(size):
+                derivation = derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
+                if not derivation: break
+                tree = GetString(derivation._yield).c_str()
+                yield tree.decode('utf8')
+        finally:
+            del derivations
 
     def kbest_features(self, size):
         cdef kb.KBestDerivations[FastSparseVector[weight_t], kb.FeatureVectorTraversal]* derivations = new kb.KBestDerivations[FastSparseVector[weight_t], kb.FeatureVectorTraversal](self.hg[0], size)
         cdef kb.KBestDerivations[FastSparseVector[weight_t], kb.FeatureVectorTraversal].Derivation* derivation
         cdef SparseVector fmap
         cdef unsigned k
-        for k in range(size):
-            derivation = derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
-            if not derivation: break
-            fmap = SparseVector()
-            fmap.vector = new FastSparseVector[weight_t](derivation._yield)
-            yield fmap
-        del derivations
+        try:
+            for k in range(size):
+                derivation = derivations.LazyKthBest(self.hg.nodes_.size() - 1, k)
+                if not derivation: break
+                fmap = SparseVector()
+                fmap.vector = new FastSparseVector[weight_t](derivation._yield)
+                yield fmap
+        finally:
+            del derivations
 
     def sample(self, unsigned n):
         cdef vector[hypergraph.Hypothesis]* hypos = new vector[hypergraph.Hypothesis]()
@@ -73,10 +79,12 @@ cdef class Hypergraph:
         hypergraph.sample_hypotheses(self.hg[0], n, self.rng, hypos)
         cdef str sentence
         cdef unsigned k
-        for k in range(hypos.size()):
-            sentence = GetString(hypos[0][k].words).c_str()
-            yield sentence.decode('utf8')
-        del hypos
+        try:
+            for k in range(hypos.size()):
+                sentence = GetString(hypos[0][k].words).c_str()
+                yield sentence.decode('utf8')
+        finally:
+            del hypos
 
     # TODO richer k-best/sample output (feature vectors, trees?)
 
@@ -89,6 +97,8 @@ cdef class Hypergraph:
              preserve_mask = new hypergraph.EdgeMask(self.hg.edges_.size())
              preserve_mask[0][hypergraph.GetFullWordEdgeIndex(self.hg[0])] = True
         self.hg.PruneInsideOutside(beam_alpha, density, preserve_mask, False, 1, False)
+        if preserve_mask:
+            del preserve_mask
 
     def lattice(self): # TODO direct hg -> lattice conversion in cdec
         cdef str plf = hypergraph.AsPLF(self.hg[0], True).c_str()
diff --git a/python/src/mteval.pxi b/python/src/mteval.pxi
index dabdf927..9afb6fe1 100644
--- a/python/src/mteval.pxi
+++ b/python/src/mteval.pxi
@@ -56,6 +56,37 @@ cdef class SufficientStats:
         result.metric = x.metric
         return result
 
+cdef class CandidateSet:
+    cdef shared_ptr[mteval.SegmentEvaluator]* scorer
+    cdef mteval.EvaluationMetric* metric
+    cdef mteval.CandidateSet* cs
+
+    def __cinit__(self, SegmentEvaluator evaluator):
+        self.scorer = new shared_ptr[mteval.SegmentEvaluator](evaluator.scorer[0])
+        self.metric = evaluator.metric
+        self.cs = new mteval.CandidateSet()
+
+    def __dealloc__(self):
+        del self.scorer
+        del self.cs
+
+    def __len__(self):
+        return self.cs.size()
+
+    def __getitem__(self, unsigned k):
+        cdef Candidate candidate = Candidate()
+        candidate.candidate = &self.cs[0][k]
+        candidate.score = self.metric.ComputeScore(self.cs[0][k].eval_feats)
+        return candidate
+
+    def __iter__(self):
+        cdef unsigned i
+        for i in range(len(self)):
+            yield self[i]
+
+    def add_kbest(self, Hypergraph hypergraph, unsigned k):
+        self.cs.AddKBestCandidates(hypergraph.hg[0], k, self.scorer.get())
+
 cdef class SegmentEvaluator:
     cdef shared_ptr[mteval.SegmentEvaluator]* scorer
     cdef mteval.EvaluationMetric* metric
@@ -72,23 +103,17 @@ cdef class SegmentEvaluator:
         self.scorer.get().Evaluate(hyp, sf.stats)
         return sf
 
-    def candidate_set(self, Hypergraph hypergraph, unsigned k):
-        cdef mteval.CandidateSet* cs = new mteval.CandidateSet()
-        cs.AddKBestCandidates(hypergraph.hg[0], k, self.scorer.get())
-        cdef Candidate candidate
-        cdef unsigned i
-        for i in range(cs.size()):
-            candidate = Candidate()
-            candidate.candidate = &cs[0][i]
-            candidate.score = self.metric.ComputeScore(cs[0][i].eval_feats)
-            yield candidate
-        del cs
+    def candidate_set(self):
+        return CandidateSet(self)
 
 cdef class Scorer:
     cdef string* name
 
     def __cinit__(self, char* name):
         self.name = new string(name)
+
+    def __dealloc__(self):
+        del self.name
     
     def __call__(self, refs):
         cdef mteval.EvaluationMetric* metric = mteval.Instance(self.name[0])
diff --git a/python/src/vectors.pxi b/python/src/vectors.pxi
index 233c9530..fc0c365f 100644
--- a/python/src/vectors.pxi
+++ b/python/src/vectors.pxi
@@ -1,16 +1,20 @@
 from cython.operator cimport preincrement as pinc
 
 cdef class DenseVector:
-    cdef vector[weight_t]* vector
+    cdef vector[weight_t]* vector # Not owned by DenseVector
+
+    def __len__(self):
+        return self.vector.size()
 
     def __getitem__(self, char* fname):
-        cdef unsigned fid = FDConvert(fname)
-        if fid <= self.vector.size():
+        cdef int fid = FDConvert(fname)
+        if 0 <= fid < self.vector.size():
             return self.vector[0][fid]
         raise KeyError(fname)
     
     def __setitem__(self, char* fname, float value):
-        cdef unsigned fid = FDConvert(<char *>fname)
+        cdef int fid = FDConvert(<char *>fname)
+        if fid < 0: raise KeyError(fname)
         if self.vector.size() <= fid:
             self.vector.resize(fid + 1)
         self.vector[0][fid] = value
@@ -32,21 +36,30 @@ cdef class DenseVector:
 cdef class SparseVector:
     cdef FastSparseVector[weight_t]* vector
 
+    def __dealloc__(self):
+        del self.vector
+
+    def copy(self):
+        return self * 1
+
     def __getitem__(self, char* fname):
-        cdef unsigned fid = FDConvert(fname)
+        cdef int fid = FDConvert(fname)
+        if fid < 0: raise KeyError(fname)
         return self.vector.value(fid)
     
     def __setitem__(self, char* fname, float value):
-        cdef unsigned fid = FDConvert(<char *>fname)
+        cdef int fid = FDConvert(<char *>fname)
+        if fid < 0: raise KeyError(fname)
         self.vector.set_value(fid, value)
 
     def __iter__(self):
         cdef FastSparseVector[weight_t].const_iterator* it = new FastSparseVector[weight_t].const_iterator(self.vector[0], False)
-        cdef str fname
-        for i in range(self.vector.size()):
-            fname = FDConvert(it[0].ptr().first).c_str()
-            yield (fname, it[0].ptr().second)
-            pinc(it[0])
+        try:
+            for i in range(self.vector.size()):
+                yield (FDConvert(it[0].ptr().first).c_str(), it[0].ptr().second)
+                pinc(it[0]) # ++it
+        finally:
+            del it
 
     def dot(self, other):
         if isinstance(other, DenseVector):
@@ -54,12 +67,6 @@ cdef class SparseVector:
         elif isinstance(other, SparseVector):
             return self.vector.dot((<SparseVector> other).vector[0])
         raise TypeError('cannot take the dot product of %s and SparseVector' % type(other))
-
-    def todense(self):
-        cdef DenseVector dense = DenseVector()
-        dense.vector = new vector[weight_t]()
-        self.vector.init_vector(dense.vector)
-        return dense
     
     def __richcmp__(SparseVector x, SparseVector y, int op):
         if op == 2: # ==
diff --git a/python/test.py b/python/test.py
index b3900eef..8069aa0a 100644
--- a/python/test.py
+++ b/python/test.py
@@ -60,3 +60,6 @@ print forest.viterbi_source_tree()
 # Compare 1best and reference feature vectors
 fref = forest.viterbi_features()
 print dict(fsrc - fref)
+
+# Prune hypergraph
+forest.prune(density=100)