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#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());
}
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