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-rw-r--r--decoder/ff_source_syntax.cc232
1 files changed, 232 insertions, 0 deletions
diff --git a/decoder/ff_source_syntax.cc b/decoder/ff_source_syntax.cc
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--- /dev/null
+++ b/decoder/ff_source_syntax.cc
@@ -0,0 +1,232 @@
+#include "ff_source_syntax.h"
+
+#include <sstream>
+#include <stack>
+
+#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)))
+
+// log transform to make long spans cluster together
+// but preserve differences
+inline int SpanSizeTransform(unsigned span_size) {
+ if (!span_size) return 0;
+ return static_cast<int>(log(span_size+1) / log(1.39)) - 1;
+}
+
+struct SourceSyntaxFeaturesImpl {
+ SourceSyntaxFeaturesImpl() {}
+
+ 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;
+ 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);
+ //int& fid_cat = fids_cat(i,j);
+ int& fid_ef = fids_ef(i,j)[&rule];
+ if (fid_ef <= 0) {
+ ostringstream os;
+ //ostringstream os2;
+ os << "SYN:" << TD::Convert(lhs);
+ //os2 << "SYN:" << TD::Convert(lhs) << '_' << SpanSizeTransform(j - i);
+ //fid_cat = FD::Convert(os2.str());
+ os << ':';
+ unsigned ntc = 0;
+ for (unsigned k = 0; k < rule.f_.size(); ++k) {
+ if (k > 0) os << '_';
+ int fj = rule.f_[k];
+ 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());
+ }
+ //if (fid_cat > 0)
+ // feats->set_value(fid_cat, 1.0);
+ if (fid_ef > 0)
+ feats->set_value(fid_ef, 1.0);
+ return lhs;
+ }
+
+ Array2D<WordID> src_tree; // src_tree(i,j) NT = type
+ // mutable Array2D<int> fids_cat; // this tends to overfit baddly
+ mutable Array2D<map<const TRule*, int> > fids_ef; // fires for fully lexicalized
+};
+
+SourceSyntaxFeatures::SourceSyntaxFeatures(const string& param) :
+ FeatureFunction(sizeof(WordID)) {
+ impl = new SourceSyntaxFeaturesImpl;
+}
+
+SourceSyntaxFeatures::~SourceSyntaxFeatures() {
+ delete impl;
+ impl = NULL;
+}
+
+void SourceSyntaxFeatures::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 SourceSyntaxFeatures::PrepareForInput(const SentenceMetadata& smeta) {
+ impl->InitializeGrids(smeta.GetSGMLValue("src_tree"), smeta.GetSourceLength());
+}
+
+struct SourceSpanSizeFeaturesImpl {
+ SourceSpanSizeFeaturesImpl() {}
+
+ void InitializeGrids(unsigned src_len) {
+ fids.clear();
+ fids.resize(src_len, src_len + 1);
+ }
+
+ int FireFeatures(const TRule& rule, const int i, const int j, const WordID* ants, SparseVector<double>* feats) {
+ if (rule.Arity() > 0) {
+ int& fid = fids(i,j)[&rule];
+ if (fid <= 0) {
+ ostringstream os;
+ os << "SSS:";
+ unsigned ntc = 0;
+ for (unsigned k = 0; k < rule.f_.size(); ++k) {
+ if (k > 0) os << '_';
+ int fj = rule.f_[k];
+ if (fj <= 0) {
+ os << '[' << TD::Convert(-fj) << 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 = FD::Convert(os.str());
+ }
+ if (fid > 0)
+ feats->set_value(fid, 1.0);
+ }
+ return SpanSizeTransform(j - i);
+ }
+
+ mutable Array2D<map<const TRule*, int> > fids;
+};
+
+SourceSpanSizeFeatures::SourceSpanSizeFeatures(const string& param) :
+ FeatureFunction(sizeof(char)) {
+ impl = new SourceSpanSizeFeaturesImpl;
+}
+
+SourceSpanSizeFeatures::~SourceSpanSizeFeatures() {
+ delete impl;
+ impl = NULL;
+}
+
+void SourceSpanSizeFeatures::TraversalFeaturesImpl(const SentenceMetadata& smeta,
+ const Hypergraph::Edge& edge,
+ const vector<const void*>& ant_contexts,
+ SparseVector<double>* features,
+ SparseVector<double>* estimated_features,
+ void* context) const {
+ int ants[8];
+ for (unsigned i = 0; i < ant_contexts.size(); ++i)
+ ants[i] = *static_cast<const char*>(ant_contexts[i]);
+
+ *static_cast<char*>(context) =
+ impl->FireFeatures(*edge.rule_, edge.i_, edge.j_, ants, features);
+}
+
+void SourceSpanSizeFeatures::PrepareForInput(const SentenceMetadata& smeta) {
+ impl->InitializeGrids(smeta.GetSourceLength());
+}
+
+