File size: 5,195 Bytes
71e354e | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 | #ifndef CPPJIBEA_HMMSEGMENT_H
#define CPPJIBEA_HMMSEGMENT_H
#include <iostream>
#include <fstream>
#include <memory.h>
#include <cassert>
#include "HMMModel.hpp"
#include "SegmentBase.hpp"
namespace cppjieba {
class HMMSegment: public SegmentBase {
public:
HMMSegment(const string& filePath)
: model_(new HMMModel(filePath)), isNeedDestroy_(true) {
}
HMMSegment(const HMMModel* model)
: model_(model), isNeedDestroy_(false) {
}
~HMMSegment() {
if (isNeedDestroy_) {
delete model_;
}
}
void Cut(const string& sentence,
vector<string>& words) const {
vector<Word> tmp;
Cut(sentence, tmp);
GetStringsFromWords(tmp, words);
}
void Cut(const string& sentence,
vector<Word>& words) const {
PreFilter pre_filter(symbols_, sentence);
PreFilter::Range range;
vector<WordRange> wrs;
wrs.reserve(sentence.size()/2);
while (pre_filter.HasNext()) {
range = pre_filter.Next();
Cut(range.begin, range.end, wrs);
}
words.clear();
words.reserve(wrs.size());
GetWordsFromWordRanges(sentence, wrs, words);
}
void Cut(RuneStrArray::const_iterator begin, RuneStrArray::const_iterator end, vector<WordRange>& res) const {
RuneStrArray::const_iterator left = begin;
RuneStrArray::const_iterator right = begin;
while (right != end) {
if (right->rune < 0x80) {
if (left != right) {
InternalCut(left, right, res);
}
left = right;
do {
right = SequentialLetterRule(left, end);
if (right != left) {
break;
}
right = NumbersRule(left, end);
if (right != left) {
break;
}
right ++;
} while (false);
WordRange wr(left, right - 1);
res.push_back(wr);
left = right;
} else {
right++;
}
}
if (left != right) {
InternalCut(left, right, res);
}
}
private:
// sequential letters rule
RuneStrArray::const_iterator SequentialLetterRule(RuneStrArray::const_iterator begin, RuneStrArray::const_iterator end) const {
Rune x = begin->rune;
if (('a' <= x && x <= 'z') || ('A' <= x && x <= 'Z')) {
begin ++;
} else {
return begin;
}
while (begin != end) {
x = begin->rune;
if (('a' <= x && x <= 'z') || ('A' <= x && x <= 'Z') || ('0' <= x && x <= '9')) {
begin ++;
} else {
break;
}
}
return begin;
}
//
RuneStrArray::const_iterator NumbersRule(RuneStrArray::const_iterator begin, RuneStrArray::const_iterator end) const {
Rune x = begin->rune;
if ('0' <= x && x <= '9') {
begin ++;
} else {
return begin;
}
while (begin != end) {
x = begin->rune;
if ( ('0' <= x && x <= '9') || x == '.') {
begin++;
} else {
break;
}
}
return begin;
}
void InternalCut(RuneStrArray::const_iterator begin, RuneStrArray::const_iterator end, vector<WordRange>& res) const {
vector<size_t> status;
Viterbi(begin, end, status);
RuneStrArray::const_iterator left = begin;
RuneStrArray::const_iterator right;
for (size_t i = 0; i < status.size(); i++) {
if (status[i] % 2) { //if (HMMModel::E == status[i] || HMMModel::S == status[i])
right = begin + i + 1;
WordRange wr(left, right - 1);
res.push_back(wr);
left = right;
}
}
}
void Viterbi(RuneStrArray::const_iterator begin,
RuneStrArray::const_iterator end,
vector<size_t>& status) const {
size_t Y = HMMModel::STATUS_SUM;
size_t X = end - begin;
size_t XYSize = X * Y;
size_t now, old, stat;
double tmp, endE, endS;
vector<int> path(XYSize);
vector<double> weight(XYSize);
//start
for (size_t y = 0; y < Y; y++) {
weight[0 + y * X] = model_->startProb[y] + model_->GetEmitProb(model_->emitProbVec[y], begin->rune, MIN_DOUBLE);
path[0 + y * X] = -1;
}
double emitProb;
for (size_t x = 1; x < X; x++) {
for (size_t y = 0; y < Y; y++) {
now = x + y*X;
weight[now] = MIN_DOUBLE;
path[now] = HMMModel::E; // warning
emitProb = model_->GetEmitProb(model_->emitProbVec[y], (begin+x)->rune, MIN_DOUBLE);
for (size_t preY = 0; preY < Y; preY++) {
old = x - 1 + preY * X;
tmp = weight[old] + model_->transProb[preY][y] + emitProb;
if (tmp > weight[now]) {
weight[now] = tmp;
path[now] = preY;
}
}
}
}
endE = weight[X-1+HMMModel::E*X];
endS = weight[X-1+HMMModel::S*X];
stat = 0;
if (endE >= endS) {
stat = HMMModel::E;
} else {
stat = HMMModel::S;
}
status.resize(X);
for (int x = X -1 ; x >= 0; x--) {
status[x] = stat;
stat = path[x + stat*X];
}
}
const HMMModel* model_;
bool isNeedDestroy_;
}; // class HMMSegment
} // namespace cppjieba
#endif
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