added Gesa's alternative source syntax features

1 files changed, 159 insertions, 0 deletions

diff --git a/decoder/ff_source_syntax2.cc b/decoder/ff_source_syntax2.cc
new file mode 100644
index 00000000..08ece917
--- /dev/null
+++ b/decoder/ff_source_syntax2.cc
@@ -0,0 +1,159 @@
+#include "ff_source_syntax2.h"
+
+#include <sstream>
+#include <stack>
+#include <string>
+#include <tr1/unordered_set>
+
+#include "sentence_metadata.h"
+#include "array2d.h"
+#include "filelib.h"
+
+using namespace std;
+
+// implements the source side syntax features described in Blunsom et al. (EMNLP 2008)
+// source trees must be represented in Penn Treebank format, e.g.
+//     (S (NP John) (VP (V left)))
+
+struct SourceSyntaxFeatures2Impl {
+  SourceSyntaxFeatures2Impl(const string& param) {
+    if (!(param.compare("") == 0)) {
+      string triggered_features_fn = param;
+      ReadFile triggered_features(triggered_features_fn);
+      string in;
+      while(getline(*triggered_features, in)) {
+        feature_filter.insert(FD::Convert(in));
+      }
+    }
+  }
+
+  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) {
+    //cerr << "TREE: " << tree << endl;
+    stack<pair<int, WordID> > stk;  // first = i, second = category
+    pair<int, WordID> cur_cat; cur_cat.first = -1;
+    unsigned i = 0;
+    unsigned p = 0;
+    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) {
+          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;
+    }
+    //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);
+    int& fid_ef = fids_ef(i,j)[&rule];
+    ostringstream os;
+    os << "SYN:" << TD::Convert(lhs);
+    os << ':';
+    unsigned ntc = 0;
+    for (unsigned k = 0; k < rule.f_.size(); ++k) {
+      int fj = rule.f_[k];
+      if (k > 0 && fj <= 0) os << '_';
+      if (fj <= 0) {
+        os << '[' << TD::Convert(ants[ntc++]) << ']';
+      } /*else {
+        os << TD::Convert(fj);
+      }*/
+    }
+    os << ':';
+    for (unsigned k = 0; k < rule.e_.size(); ++k) {
+      const int ei = rule.e_[k];
+      if (k > 0) os << '_';
+      if (ei <= 0)
+        os << '[' << (1-ei) << ']';
+      else
+        os << TD::Convert(ei);
+    }
+    fid_ef = FD::Convert(os.str());
+    //cerr << "FEATURE: " << os.str() << endl;
+    //cerr << "FID_EF: " << fid_ef << endl;
+    if (feature_filter.find(fid_ef) != feature_filter.end()) {
+      cerr << "SYN-Feature was trigger more than once on training set." << endl;
+      feats->set_value(fid_ef, 1.0);
+    }
+    else cerr << "SYN-Feature was triggered less than once on training set." << 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
+  tr1::unordered_set<int> feature_filter;
+
+};
+
+SourceSyntaxFeatures2::SourceSyntaxFeatures2(const string& param) :
+    FeatureFunction(sizeof(WordID)) {
+  impl = new SourceSyntaxFeatures2Impl(param);
+}
+
+SourceSyntaxFeatures2::~SourceSyntaxFeatures2() {
+  delete impl;
+  impl = NULL;
+}
+
+void SourceSyntaxFeatures2::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 SourceSyntaxFeatures2::PrepareForInput(const SentenceMetadata& smeta) {
+  impl->InitializeGrids(smeta.GetSGMLValue("src_tree"), smeta.GetSourceLength());
+}