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-rw-r--r--decoder/ff_soft_syntax_mindist.cc235
1 files changed, 235 insertions, 0 deletions
diff --git a/decoder/ff_soft_syntax_mindist.cc b/decoder/ff_soft_syntax_mindist.cc
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+++ b/decoder/ff_soft_syntax_mindist.cc
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+#include "ff_soft_syntax_mindist.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))).
+//
+// This variant accepts fuzzy matches, choosing the constituent with
+// minimum distance.
+
+struct SoftSyntaxFeaturesMindistImpl {
+ SoftSyntaxFeaturesMindistImpl(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_ef.clear();
+ src_tree.clear();
+ 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];
+ string lhs_to_str = TD::Convert(lhs);
+ int min_dist;
+ string min_dist_label;
+ if (lhs_to_str.compare("XX") != 0) {
+ min_dist = 0;
+ min_dist_label = lhs_to_str;
+ }
+ else {
+ int ok = 0;
+ for (unsigned int k = 1; k < (j - i); k++) {
+ min_dist = k;
+ for (unsigned int l = 0; l <= k; l++) {
+ int l_add = i-l;
+ int r_add = j+(k-l);
+ if ((l_add < src_tree.width() && r_add < src_tree.height()) && (TD::Convert(src_tree(l_add, r_add)).compare("XX") != 0)) {
+ ok = 1;
+ min_dist_label = (TD::Convert(src_tree(l_add, r_add)));
+ break;
+ }
+ else {
+ int l_rem= i+l;
+ int r_rem = j-(k-l);
+ if ((l_rem < src_tree.width() && r_rem < src_tree.height()) && TD::Convert(src_tree(l_rem, r_rem)).compare("XX") != 0) {
+ ok = 1;
+ min_dist_label = (TD::Convert(src_tree(l_rem, r_rem)));
+ break;
+ }
+ }
+ }
+ if (ok) break;
+ }
+ }
+ //cerr << "SPAN: " << i << " " << j << endl;
+ //cerr << "MINDIST: " << min_dist << endl;
+ //cerr << "MINDISTLABEL: " << min_dist_label << endl;
+ 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 (min_dist_label.compare(label) == 0) {
+ if (min_dist == 0) {
+ os << "SYN:" << label << "_conform";
+ }
+ else {
+ os << "SYN:" << label << "_cross";
+ }
+ fid_ef = FD::Convert(os.str());
+ //cerr << "Feature :" << os.str() << endl;
+ feats->set_value(fid_ef, 1.0);
+ }
+ break;
+ case '_':
+ os << "SYN:" << label;
+ fid_ef = FD::Convert(os.str());
+ if (min_dist_label.compare(label) == 0) {
+ //cerr << "Feature: " << os.str() << endl;
+ if (min_dist == 0) {
+ feats->set_value(fid_ef, 1.0);
+ }
+ else {
+ //cerr << "Feature: " << os.str() << endl;
+ feats->set_value(fid_ef, -1.0);
+ }
+ }
+ break;
+ case '+':
+ if (min_dist_label.compare(label) == 0) {
+ os << "SYN:" << label << "_conform";
+ fid_ef = FD::Convert(os.str());
+ if (min_dist == 0) {
+ //cerr << "Feature: " << os.str() << endl;
+ feats->set_value(fid_ef, 1.0);
+ }
+ }
+ break;
+ case '-':
+ //cerr << "-" << endl;
+ if (min_dist_label.compare(label) != 0) {
+ os << "SYN:" << label << "_cross";
+ fid_ef = FD::Convert(os.str());
+ if (min_dist > 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;
+};
+
+SoftSyntaxFeaturesMindist::SoftSyntaxFeaturesMindist(const string& param) :
+ FeatureFunction(sizeof(WordID)) {
+ impl = new SoftSyntaxFeaturesMindistImpl(param);
+}
+
+SoftSyntaxFeaturesMindist::~SoftSyntaxFeaturesMindist() {
+ delete impl;
+ impl = NULL;
+}
+
+void SoftSyntaxFeaturesMindist::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 SoftSyntaxFeaturesMindist::PrepareForInput(const SentenceMetadata& smeta) {
+ impl->InitializeGrids(smeta.GetSGMLValue("src_tree"), smeta.GetSourceLength());
+}
+