Merge pull request #64 from kho/softsyn_2

Proper implementation of soft syntactic constraint features

1 files changed, 265 insertions, 0 deletions

diff --git a/decoder/ff_soft_syn.cc b/decoder/ff_soft_syn.cc
new file mode 100644
index 00000000..2d4369d1
--- /dev/null
+++ b/decoder/ff_soft_syn.cc
@@ -0,0 +1,265 @@
+/*
+ * ff_soft_syn.cc
+ *
+ */
+#include "ff_soft_syn.h"
+
+#include "filelib.h"
+#include "stringlib.h"
+#include "hg.h"
+#include "sentence_metadata.h"
+#include "ff_const_reorder_common.h"
+
+#include <string>
+#include <vector>
+#include <stdio.h>
+
+using namespace std;
+using namespace const_reorder;
+
+typedef HASH_MAP<std::string, vector<string> > MapFeatures;
+
+struct SoftSynFeatureImpl {
+  SoftSynFeatureImpl(const string& /*params*/) {
+    parsed_tree_ = NULL;
+    map_features_ = NULL;
+  }
+
+  ~SoftSynFeatureImpl() { FreeSentenceVariables(); }
+
+  void InitializeInputSentence(const std::string& parse_file) {
+    FreeSentenceVariables();
+    parsed_tree_ = ReadParseTree(parse_file);
+
+    // we can do the features "off-line"
+    map_features_ = new MapFeatures();
+    InitializeFeatures(map_features_);
+  }
+
+  /*
+   * ff_const_reorder.cc::ConstReorderFeatureImpl also defines this function
+   */
+  void FindConsts(const SParsedTree* tree, int begin, int end,
+                  vector<STreeItem*>& consts) {
+    STreeItem* item;
+    item = tree->m_vecTerminals[begin]->m_ptParent;
+    while (true) {
+      while (item->m_ptParent != NULL &&
+             item->m_ptParent->m_iBegin == item->m_iBegin &&
+             item->m_ptParent->m_iEnd <= end)
+        item = item->m_ptParent;
+
+      if (item->m_ptParent == NULL && item->m_vecChildren.size() == 1 &&
+          strcmp(item->m_pszTerm, "ROOT") == 0)
+        item = item->m_vecChildren[0];  // we automatically add a "ROOT" node at
+                                        // the top, skip it if necessary.
+
+      consts.push_back(item);
+      if (item->m_iEnd < end)
+        item = tree->m_vecTerminals[item->m_iEnd + 1]->m_ptParent;
+      else
+        break;
+    }
+  }
+
+  /*
+   * according to Marton & Resnik (2008)
+   * a span cann't have both X+ style and X= style features
+   * a constituent XP is crossed only if the span not only covers parts of XP's
+   *content, but also covers one or more words outside XP
+   * a span may have X+, Y+
+   *
+   * (note, we refer X* features to X= features in Marton & Resnik (2008))
+   */
+  void GenerateSoftFeature(int begin, int end, const SParsedTree* tree,
+                           vector<string>& vecFeature) {
+    vector<STreeItem*> vecNode;
+    FindConsts(tree, begin, end, vecNode);
+
+    if (vecNode.size() == 1) {
+      // match to one constituent
+      string feature_name = string(vecNode[0]->m_pszTerm) + string("*");
+      vecFeature.push_back(feature_name);
+    } else {
+      // match to multiple constituents, find the lowest common parent (lcp)
+      STreeItem* lcp = vecNode[0];
+      while (lcp->m_iEnd < end) lcp = lcp->m_ptParent;
+
+      for (size_t i = 0; i < vecNode.size(); i++) {
+        STreeItem* item = vecNode[i];
+
+        while (item != lcp) {
+          if (item->m_iBegin < begin || item->m_iEnd > end) {
+            // item is crossed
+            string feature_name = string(item->m_pszTerm) + string("+");
+            vecFeature.push_back(feature_name);
+          }
+          if (item->m_iBrotherIndex > 0 &&
+              item->m_ptParent->m_vecChildren[item->m_iBrotherIndex - 1]
+                      ->m_iBegin >= begin &&
+              item->m_ptParent->m_vecChildren[item->m_iBrotherIndex - 1]
+                      ->m_iEnd <= end)
+            break;  // we don't want to collect crossed constituents twice
+          item = item->m_ptParent;
+        }
+      }
+    }
+  }
+
+  void GenerateSoftFeatureFromFlattenedTree(int begin, int end,
+                                            const SParsedTree* tree,
+                                            vector<string>& vecFeature) {
+    vector<STreeItem*> vecNode;
+    FindConsts(tree, begin, end, vecNode);
+
+    if (vecNode.size() == 1) {
+      // match to one constituent
+      string feature_name = string(vecNode[0]->m_pszTerm) + string("*");
+      vecFeature.push_back(feature_name);
+    } else {
+      // match to multiple constituents, see if they have a common parent
+      size_t i = 0;
+      for (i = 1; i < vecNode.size(); i++) {
+        if (vecNode[i]->m_ptParent != vecNode[0]->m_ptParent) break;
+      }
+      if (i == vecNode.size()) {
+        // they share a common parent
+        string feature_name =
+            string(vecNode[0]->m_ptParent->m_pszTerm) + string("&");
+        vecFeature.push_back(feature_name);
+      } else {
+        // they don't share a common parent, find the lowest common parent (lcp)
+        STreeItem* lcp = vecNode[0];
+        while (lcp->m_iEnd < end) lcp = lcp->m_ptParent;
+
+        for (size_t i = 0; i < vecNode.size(); i++) {
+          STreeItem* item = vecNode[i];
+
+          while (item != lcp) {
+            if (item->m_iBegin < begin || item->m_iEnd > end) {
+              // item is crossed
+              string feature_name = string(item->m_pszTerm) + string("+");
+              vecFeature.push_back(feature_name);
+            }
+            if (item->m_iBrotherIndex > 0 &&
+                item->m_ptParent->m_vecChildren[item->m_iBrotherIndex - 1]
+                        ->m_iBegin >= begin &&
+                item->m_ptParent->m_vecChildren[item->m_iBrotherIndex - 1]
+                        ->m_iEnd <= end)
+              break;  // we don't want to collect crossed constituents twice
+            item = item->m_ptParent;
+          }
+        }
+      }
+    }
+  }
+
+  void SetSoftSynFeature(const Hypergraph::Edge& edge,
+                         SparseVector<double>* features) {
+    if (parsed_tree_ == NULL) return;
+
+    // soft feature for the whole span
+    const vector<string> vecFeature =
+        GenerateSoftFeature(edge.i_, edge.j_ - 1, map_features_);
+    for (size_t i = 0; i < vecFeature.size(); i++) {
+      int f_id = FD::Convert(vecFeature[i]);
+      if (f_id) features->set_value(f_id, 1);
+    }
+  }
+
+ private:
+  const vector<string>& GenerateSoftFeature(int begin, int end,
+                                            MapFeatures* map_features) {
+    string key;
+    GenerateKey(begin, end, key);
+    MapFeatures::const_iterator iter = (*map_features).find(key);
+    assert(iter != map_features->end());
+    return iter->second;
+  }
+
+  void Byte_to_Char(unsigned char* str, int n) {
+    str[0] = (n & 255);
+    str[1] = n / 256;
+  }
+
+  void GenerateKey(int begin, int end, string& key) {
+    unsigned char szTerm[1001];
+    Byte_to_Char(szTerm, begin);
+    Byte_to_Char(szTerm + 2, end);
+    szTerm[4] = '\0';
+    key = string(szTerm, szTerm + 4);
+  }
+
+  void InitializeFeatures(MapFeatures* map_features) {
+    if (parsed_tree_ == NULL) return;
+
+    for (size_t i = 0; i < parsed_tree_->m_vecTerminals.size(); i++)
+      for (size_t j = i; j < parsed_tree_->m_vecTerminals.size(); j++) {
+        vector<string> vecFeature;
+        GenerateSoftFeature(i, j, parsed_tree_, vecFeature);
+        string key;
+        GenerateKey(i, j, key);
+        (*map_features)[key] = vecFeature;
+      }
+  }
+
+  void FreeSentenceVariables() {
+    if (parsed_tree_ != NULL) delete parsed_tree_;
+    if (map_features_ != NULL) delete map_features_;
+  }
+
+  SParsedTree* ReadParseTree(const std::string& parse_file) {
+    SParseReader* reader = new SParseReader(parse_file.c_str(), false);
+    SParsedTree* tree = reader->fnReadNextParseTree();
+    // assert(tree != NULL);
+    delete reader;
+    return tree;
+  }
+
+ private:
+  SParsedTree* parsed_tree_;
+
+  MapFeatures* map_features_;
+};
+
+SoftSynFeature::SoftSynFeature(std::string param) {
+  pimpl_ = new SoftSynFeatureImpl(param);
+  name_ = "SoftSynFeature";
+}
+
+SoftSynFeature::~SoftSynFeature() { delete pimpl_; }
+
+void SoftSynFeature::PrepareForInput(const SentenceMetadata& smeta) {
+  string parse_file = smeta.GetSGMLValue("parse");
+  if (parse_file.empty()) {
+    parse_file = smeta.GetSGMLValue("src_tree");
+  }
+  assert(parse_file.size());
+  pimpl_->InitializeInputSentence(parse_file);
+}
+
+void SoftSynFeature::TraversalFeaturesImpl(
+    const SentenceMetadata& /*smeta*/, const Hypergraph::Edge& edge,
+    const vector<const void*>& /*ant_states*/, SparseVector<double>* features,
+    SparseVector<double>* /*estimated_features*/, void* /*state*/) const {
+  pimpl_->SetSoftSynFeature(edge, features);
+}
+
+string SoftSynFeature::usage(bool /*param*/, bool /*verbose*/) {
+  return "SoftSynFeature";
+}
+
+boost::shared_ptr<FeatureFunction> CreateSoftSynFeatureModel(
+    std::string param) {
+  SoftSynFeature* ret = new SoftSynFeature(param);
+  return boost::shared_ptr<FeatureFunction>(ret);
+}
+
+boost::shared_ptr<FeatureFunction> SoftSynFeatureFactory::Create(
+    std::string param) const {
+  return CreateSoftSynFeatureModel(param);
+}
+
+std::string SoftSynFeatureFactory::usage(bool params, bool verbose) const {
+  return SoftSynFeature::usage(params, verbose);
+}