added Gesa's soft syntactic features

1 files changed, 201 insertions, 0 deletions

diff --git a/decoder/ff_soft_syntax.cc b/decoder/ff_soft_syntax.cc
new file mode 100644
index 00000000..9981fa45
--- /dev/null
+++ b/decoder/ff_soft_syntax.cc
@@ -0,0 +1,201 @@
+#include "ff_soft_syntax.h"
+
+#include <cstdio>
+#include <sstream>
+#include <stack>
+#include <string>
+#include <vector>
+
+#include "sentence_metadata.h"
+#include "stringlib.h"
+#include "array2d.h"
+#include "filelib.h"
+
+using namespace std;
+
+// Implements the soft syntactic features described in 
+// Marton and Resnik (2008): "Soft Syntacitc Constraints for Hierarchical Phrase-Based Translation".
+// Source trees must be represented in Penn Treebank format,
+// e.g. (S (NP John) (VP (V left))).
+
+struct SoftSyntacticFeaturesImpl {
+  SoftSyntacticFeaturesImpl(const string& param) {
+    vector<string> labels = SplitOnWhitespace(param);
+	for (unsigned int i = 0; i < labels.size(); i++) 
+      //cerr << "Labels: " << labels.at(i) << endl;
+    for (unsigned int i = 0; i < labels.size(); i++) {
+      string label = labels.at(i);
+      pair<string, string> feat_label;
+      feat_label.first = label.substr(0, label.size() - 1);
+      feat_label.second = label.at(label.size() - 1);
+      feat_labels.push_back(feat_label);
+    }
+}
+
+  void InitializeGrids(const string& tree, unsigned src_len) {
+    assert(tree.size() > 0);
+    //fids_cat.clear();
+    fids_ef.clear();
+    src_tree.clear();
+    //fids_cat.resize(src_len, src_len + 1);
+    fids_ef.resize(src_len, src_len + 1);
+    src_tree.resize(src_len, src_len + 1, TD::Convert("XX"));
+    ParseTreeString(tree, src_len);
+  }
+
+  void ParseTreeString(const string& tree, unsigned src_len) {
+    stack<pair<int, WordID> > stk;  // first = i, second = category
+    pair<int, WordID> cur_cat; cur_cat.first = -1;
+    unsigned i = 0;
+    unsigned p = 0;
+    //cerr << "String " << tree << endl;
+    while(p < tree.size()) {
+      const char cur = tree[p];
+      if (cur == '(') {
+        stk.push(cur_cat);
+        ++p;
+        unsigned k = p + 1;
+        while (k < tree.size() && tree[k] != ' ') { ++k; }
+        cur_cat.first = i;
+        cur_cat.second = TD::Convert(tree.substr(p, k - p));
+        //cerr << "NT: '" << tree.substr(p, k-p) << "' (i=" << i << ")\n";
+        p = k + 1;
+      } else if (cur == ')') {
+        unsigned k = p;
+        while (k < tree.size() && tree[k] == ')') { ++k; }
+        const unsigned num_closes = k - p;
+        for (unsigned ci = 0; ci < num_closes; ++ci) {
+          // cur_cat.second spans from cur_cat.first to i
+          //cerr << TD::Convert(cur_cat.second) << " from " << cur_cat.first << " to " << i << endl;
+          // NOTE: unary rule chains end up being labeled with the top-most category
+          src_tree(cur_cat.first, i) = cur_cat.second;
+          cur_cat = stk.top();
+          stk.pop();
+        }
+        p = k;
+        while (p < tree.size() && (tree[p] == ' ' || tree[p] == '\t')) { ++p; }
+      } else if (cur == ' ' || cur == '\t') {
+        cerr << "Unexpected whitespace in: " << tree << endl;
+        abort();
+      } else { // terminal symbol
+        unsigned k = p + 1;
+        do {
+          while (k < tree.size() && tree[k] != ')' && tree[k] != ' ') { ++k; }
+          // cerr << "TERM: '" << tree.substr(p, k-p) << "' (i=" << i << ")\n";
+          ++i;
+          assert(i <= src_len);
+          while (k < tree.size() && tree[k] == ' ') { ++k; }
+          p = k;
+        } while (p < tree.size() && tree[p] != ')');
+      }
+    }
+    //cerr << "i=" << i << "  src_len=" << src_len << endl;
+    assert(i == src_len);  // make sure tree specified in src_tree is
+                           // the same length as the source sentence
+  }
+
+  WordID FireFeatures(const TRule& rule, const int i, const int j, const WordID* ants, SparseVector<double>* feats) {
+    //cerr << "fire features: " << rule.AsString() << " for " << i << "," << j << endl;
+    const WordID lhs = src_tree(i,j);
+	string lhs_str = TD::Convert(lhs);
+    //cerr << "LHS: " << lhs_str << " from " << i << " to " << j << endl;
+	//cerr << "RULE :"<< rule << endl;
+    int& fid_ef = fids_ef(i,j)[&rule];
+    for (unsigned int i = 0; i < feat_labels.size(); i++) {
+      ostringstream os;
+      string label = feat_labels.at(i).first;
+      //cerr << "This Label: " << label << endl;
+      char feat_type = (char) feat_labels.at(i).second.c_str()[0];
+      //cerr << "feat_type: " << feat_type << endl;
+      switch(feat_type) {
+        case '2':
+          if (lhs_str.compare(label) == 0) {
+            os << "SYN:" << label << "_conform";
+          }
+          else {
+            os << "SYN:" << label << "_cross";
+          }
+          fid_ef = FD::Convert(os.str());
+          if (fid_ef > 0) {
+            //cerr << "Feature :" << os.str() << endl;
+            feats->set_value(fid_ef, 1.0);
+          }
+          break;
+        case '_':
+          os << "SYN:" << label;
+          fid_ef = FD::Convert(os.str());
+          if (lhs_str.compare(label) == 0) {
+            if (fid_ef > 0) {
+            //cerr << "Feature: " << os.str() << endl;
+              feats->set_value(fid_ef, 1.0);
+            }
+          }
+          else {
+            if (fid_ef > 0) {
+              //cerr << "Feature: " << os.str() << endl;
+              feats->set_value(fid_ef, -1.0);
+            }
+          }
+          break;
+        case '+':
+          if (lhs_str.compare(label) == 0) {
+            os << "SYN:" << label << "_conform";
+            fid_ef = FD::Convert(os.str());
+            if (fid_ef > 0) {
+              //cerr << "Feature: " << os.str() << endl;
+              feats->set_value(fid_ef, 1.0);
+            }
+          }
+          break;
+        case '-': 
+          //cerr << "-" << endl;           
+          if (lhs_str.compare(label) != 0) {
+            os << "SYN:" << label << "_cross";
+            fid_ef = FD::Convert(os.str());
+            if (fid_ef > 0) {
+              //cerr << "Feature :" << os.str() << endl;
+              feats->set_value(fid_ef, 1.0);
+            }
+          }
+          break;
+        os.clear();
+        os.str("");
+      }
+      //cerr << "Feature: " << os.str() << endl;
+      //cerr << endl;
+    }
+    return lhs;
+  }
+
+  Array2D<WordID> src_tree;  // src_tree(i,j) NT = type
+  mutable Array2D<map<const TRule*, int> > fids_ef;    // fires for fully lexicalized
+  vector<pair<string, string> > feat_labels;
+};
+
+SoftSyntacticFeatures::SoftSyntacticFeatures(const string& param) :
+    FeatureFunction(sizeof(WordID)) {
+  impl = new SoftSyntacticFeaturesImpl(param);
+}
+
+SoftSyntacticFeatures::~SoftSyntacticFeatures() {
+  delete impl;
+  impl = NULL;
+}
+
+void SoftSyntacticFeatures::TraversalFeaturesImpl(const SentenceMetadata& smeta,
+                                     const Hypergraph::Edge& edge,
+                                     const vector<const void*>& ant_contexts,
+                                     SparseVector<double>* features,
+                                     SparseVector<double>* estimated_features,
+                                     void* context) const {
+  WordID ants[8];
+  for (unsigned i = 0; i < ant_contexts.size(); ++i)
+    ants[i] = *static_cast<const WordID*>(ant_contexts[i]);
+
+  *static_cast<WordID*>(context) =
+     impl->FireFeatures(*edge.rule_, edge.i_, edge.j_, ants, features);
+}
+
+void SoftSyntacticFeatures::PrepareForInput(const SentenceMetadata& smeta) {
+  impl->InitializeGrids(smeta.GetSGMLValue("src_tree"), smeta.GetSourceLength());
+}