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//
// CRF++ -- Yet Another CRF toolkit
//
// $Id: feature.cpp 1595 2007-02-24 10:18:32Z taku $;
//
// Copyright(C) 2005-2007 Taku Kudo <[email protected]>
//
#include "feature_index.h"
#include "common.h"
#include "node.h"
#include "path.h"
#include "tagger.h"
namespace CRFPP {
static const char *BOS[4] = { "_B-1", "_B-2", "_B-3", "_B-4"};
static const char *EOS[4] = { "_B+1", "_B+2", "_B+3", "_B+4"};
const char *FeatureIndex::get_index(char *&p,
size_t pos,
const TaggerImpl &tagger) {
if (*p++ !='[') return 0;
int col = 0;
int row = 0;
int neg = 1;
if (*p++ == '-')
neg = -1;
else
--p;
for (; *p; ++p) {
switch (*p) {
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
row = 10 * row +(*p - '0');
break;
case ',':
++p;
goto NEXT1;
default: return 0;
}
}
NEXT1:
for (; *p; ++p) {
switch (*p) {
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
col = 10 * col +(*p - '0');
break;
case ']': goto NEXT2;
default: return 0;
}
}
NEXT2:
row *= neg;
if (row < -4 || row > 4 ||
col < 0 || col >= static_cast<int>(tagger.xsize()))
return 0;
max_xsize_ = _max(max_xsize_, static_cast<unsigned int>(col + 1));
int idx = pos + row;
if (idx < 0)
return BOS[-idx-1];
if (idx >= static_cast<int>(tagger.size()))
return EOS[idx - tagger.size()];
return tagger.x(idx, col);
}
bool FeatureIndex::apply_rule(string_buffer *os,
char *p,
size_t pos,
const TaggerImpl& tagger) {
os->assign(""); // clear
const char *r;
for (; *p; p++) {
switch (*p) {
default:
*os << *p;
break;
case '%':
switch (*++p) {
case 'x':
++p;
r = get_index(p, pos, tagger);
if (!r) return false;
*os << r;
break;
default:
return false;
}
break;
}
}
*os << '\0';
return true;
}
void FeatureIndex::rebuildFeatures(TaggerImpl *tagger) {
size_t fid = tagger->feature_id();
unsigned short thread_id = tagger->thread_id();
path_freelist_[thread_id].free();
node_freelist_[thread_id].free();
for (size_t cur = 0; cur < tagger->size(); ++cur) {
int *f = feature_cache_[fid++];
for (size_t i = 0; i < y_.size(); ++i) {
Node *n = node_freelist_[thread_id].alloc();
n->clear();
n->x = cur;
n->y = i;
n->fvector = f;
tagger->set_node(n, cur, i);
}
}
for (size_t cur = 1; cur < tagger->size(); ++cur) {
int *f = feature_cache_[fid++];
for (size_t j = 0; j < y_.size(); ++j) {
for (size_t i = 0; i < y_.size(); ++i) {
Path *p = path_freelist_[thread_id].alloc();
p->clear();
p->add(tagger->node(cur-1, j),
tagger->node(cur, i));
p->fvector = f;
}
}
}
}
#define ADD { int id = this->getID(os.c_str()); \
if (id != -1) feature.push_back(id); } while (0)
bool FeatureIndex::buildFeatures(TaggerImpl *tagger) {
string_buffer os;
std::vector <int> feature;
tagger->set_feature_id(feature_cache_.size());
for (size_t cur = 0; cur < tagger->size(); ++cur) {
for (std::vector<char *>::const_iterator it = unigram_templs_.begin();
it != unigram_templs_.end(); ++it) {
CHECK_FALSE(apply_rule(&os, *it, cur, *tagger))
<< " format error: " << *it;
ADD;
}
feature_cache_.add(feature);
feature.clear();
}
for (size_t cur = 1; cur < tagger->size(); ++cur) {
for (std::vector<char *>::const_iterator it = bigram_templs_.begin();
it != bigram_templs_.end(); ++it) {
CHECK_FALSE(apply_rule(&os, *it, cur, *tagger))
<< "format error: " << *it;
ADD;
}
feature_cache_.add(feature);
feature.clear();
}
return true;
}
#undef ADD
}
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