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mosesdecoder/sigtest-filter/filter-pt.cpp
hieuhoang1972 c93569c906 #include according to Ceslav 
git-svn-id: https://mosesdecoder.svn.sourceforge.net/svnroot/mosesdecoder/trunk@3922 1f5c12ca-751b-0410-a591-d2e778427230
2011-03-10 07:10:48 +00:00

383 lines
12 KiB
C++
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#include <cstring>
#include <cassert>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include "_SuffixArraySearchApplicationBase.h"
#include <vector>
#include <iostream>
#include <set>
#ifdef WIN32
#include "WIN32_functions.h"
#else
#include <unistd.h>
#endif
typedef std::set<TextLenType> SentIdSet;
typedef std::map<std::string, SentIdSet> PhraseSetMap;
#undef min
// constants
const size_t MINIMUM_SIZE_TO_KEEP = 10000; // reduce this to improve memory usage,
// increase for speed
const std::string SEPARATOR = " ||| ";
const double ALPHA_PLUS_EPS = -1000.0; // dummy value
const double ALPHA_MINUS_EPS = -2000.0; // dummy value
// configuration params
int pfe_filter_limit = 0; // 0 = don't filter anything based on P(f|e)
bool print_cooc_counts = false; // add cooc counts to phrase table?
bool print_neglog_significance = false; // add -log(p) to phrase table?
double sig_filter_limit = 0; // keep phrase pairs with -log(sig) > sig_filter_limit
// higher = filter-more
bool pef_filter_only = false; // only filter based on pef
// globals
PhraseSetMap esets;
double p_111 = 0.0; // alpha
size_t nremoved_sigfilter = 0;
size_t nremoved_pfefilter = 0;
C_SuffixArraySearchApplicationBase e_sa;
C_SuffixArraySearchApplicationBase f_sa;
int num_lines;
void usage()
{
std::cerr << "\nFilter phrase table using significance testing as described\n"
<< "in H. Johnson, et al. (2007) Improving Translation Quality\n"
<< "by Discarding Most of the Phrasetable. EMNLP 2007.\n"
<< "\nUsage:\n"
<< "\n filter-pt -e english.suf-arr -f french.suf-arr\n"
<< " [-c] [-p] [-l threshold] [-n num] < PHRASE-TABLE > FILTERED-PHRASE-TABLE\n\n"
<< " [-l threshold] >0.0, a+e, or a-e: keep values that have a -log significance > this\n"
<< " [-n num ] 0, 1...: 0=no filtering, >0 sort by P(e|f) and keep the top num elements\n"
<< " [-c ] add the cooccurence counts to the phrase table\n"
<< " [-p ] add -log(significance) to the phrasetable\n\n";
exit(1);
}
struct PTEntry {
PTEntry(const std::string& str, int index);
std::string f_phrase;
std::string e_phrase;
std::string extra;
std::string scores;
float pfe;
int cf;
int ce;
int cfe;
float nlog_pte;
void set_cooc_stats(int _cef, int _cf, int _ce, float nlp) {
cfe = _cef;
cf = _cf;
ce = _ce;
nlog_pte = nlp;
}
};
PTEntry::PTEntry(const std::string& str, int index) :
cf(0), ce(0), cfe(0), nlog_pte(0.0)
{
size_t pos = 0;
std::string::size_type nextPos = str.find(SEPARATOR, pos);
this->f_phrase = str.substr(pos,nextPos);
pos = nextPos + SEPARATOR.size();
nextPos = str.find(SEPARATOR, pos);
this->e_phrase = str.substr(pos,nextPos-pos);
pos = nextPos + SEPARATOR.size();
nextPos = str.find(SEPARATOR, pos);
this->scores = str.substr(pos,nextPos-pos);
pos = nextPos + SEPARATOR.size();
this->extra = str.substr(pos);
int c = 0;
std::string::iterator i=scores.begin();
if (index > 0) {
for (; i != scores.end(); ++i) {
if ((*i) == ' ') {
c++;
if (c == index) break;
}
}
}
if (i != scores.end()) {
++i;
}
char f[24];
char *fp=f;
while (i != scores.end() && *i != ' ') {
*fp++=*i++;
}
*fp++=0;
this->pfe = atof(f);
// std::cerr << "L: " << f_phrase << " ::: " << e_phrase << " ::: " << scores << " ::: " << pfe << std::endl;
// std::cerr << "X: " << extra << "\n";
}
struct PfeComparer {
bool operator()(const PTEntry* a, const PTEntry* b) const {
return a->pfe > b->pfe;
}
};
struct NlogSigThresholder {
NlogSigThresholder(float threshold) : t(threshold) {}
float t;
bool operator()(const PTEntry* a) const {
if (a->nlog_pte < t) {
delete a;
return true;
} else return false;
}
};
std::ostream& operator << (std::ostream& os, const PTEntry& pp)
{
os << pp.f_phrase << " ||| " << pp.e_phrase;
os << " ||| " << pp.scores;
if (pp.extra.size()>0) os << " ||| " << pp.extra;
if (print_cooc_counts) os << " ||| " << pp.cfe << " " << pp.cf << " " << pp.ce;
if (print_neglog_significance) os << " ||| " << pp.nlog_pte;
return os;
}
void print(int a, int b, int c, int d, float p)
{
std::cerr << a << "\t" << b << "\t P=" << p << "\n"
<< c << "\t" << d << "\t xf=" << (double)(b)*(double)(c)/(double)(a+1)/(double)(d+1) << "\n\n";
}
// 2x2 (one-sided) Fisher's exact test
// see B. Moore. (2004) On Log Likelihood and the Significance of Rare Events
double fisher_exact(int cfe, int ce, int cf)
{
assert(cfe <= ce);
assert(cfe <= cf);
int a = cfe;
int b = (cf - cfe);
int c = (ce - cfe);
int d = (num_lines - ce - cf + cfe);
int n = a + b + c + d;
double cp = exp(lgamma(1+a+c) + lgamma(1+b+d) + lgamma(1+a+b) + lgamma(1+c+d) - lgamma(1+n) - lgamma(1+a) - lgamma(1+b) - lgamma(1+c) - lgamma(1+d));
double total_p = 0.0;
int tc = std::min(b,c);
for (int i=0; i<=tc; i++) {
total_p += cp;
// double lg = lgamma(1+a+c) + lgamma(1+b+d) + lgamma(1+a+b) + lgamma(1+c+d) - lgamma(1+n) - lgamma(1+a) - lgamma(1+b) - lgamma(1+c) - lgamma(1+d); double cp = exp(lg);
// print(a,b,c,d,cp);
double coef = (double)(b)*(double)(c)/(double)(a+1)/(double)(d+1);
cp *= coef;
++a;
--c;
++d;
--b;
}
return total_p;
}
// input: unordered list of translation options for a single source phrase
void compute_cooc_stats_and_filter(std::vector<PTEntry*>& options)
{
if (pfe_filter_limit>0 && options.size() > pfe_filter_limit) {
nremoved_pfefilter += (options.size() - pfe_filter_limit);
std::nth_element(options.begin(), options.begin()+pfe_filter_limit, options.end(), PfeComparer());
for (std::vector<PTEntry*>::iterator i=options.begin()+pfe_filter_limit; i != options.end(); ++i)
delete *i;
options.erase(options.begin()+pfe_filter_limit,options.end());
}
if (pef_filter_only) return;
SentIdSet fset;
vector<S_SimplePhraseLocationElement> locations;
//std::cerr << "Looking up f-phrase: " << options.front()->f_phrase << "\n";
locations = f_sa.locateExactPhraseInCorpus(options.front()->f_phrase.c_str());
if(locations.size()==0) {
cerr<<"No occurrences found!!\n";
}
for (vector<S_SimplePhraseLocationElement>::iterator i=locations.begin();
i != locations.end();
++i) {
fset.insert(i->sentIdInCorpus);
}
size_t cf = fset.size();
for (std::vector<PTEntry*>::iterator i=options.begin(); i != options.end(); ++i) {
const std::string& e_phrase = (*i)->e_phrase;
size_t cef=0;
SentIdSet& eset = esets[(*i)->e_phrase];
if (eset.empty()) {
//std::cerr << "Looking up e-phrase: " << e_phrase << "\n";
vector<S_SimplePhraseLocationElement> locations = e_sa.locateExactPhraseInCorpus(e_phrase.c_str());
for (vector<S_SimplePhraseLocationElement>::iterator i=locations.begin(); i!= locations.end(); ++i) {
TextLenType curSentId = i->sentIdInCorpus;
eset.insert(curSentId);
}
}
size_t ce=eset.size();
if (ce < cf) {
for (SentIdSet::iterator i=eset.begin(); i != eset.end(); ++i) {
if (fset.find(*i) != fset.end()) cef++;
}
} else {
for (SentIdSet::iterator i=fset.begin(); i != fset.end(); ++i) {
if (eset.find(*i) != eset.end()) cef++;
}
}
double nlp = -log(fisher_exact(cef, cf, ce));
(*i)->set_cooc_stats(cef, cf, ce, nlp);
if (ce < MINIMUM_SIZE_TO_KEEP) {
esets.erase(e_phrase);
}
}
std::vector<PTEntry*>::iterator new_end =
std::remove_if(options.begin(), options.end(), NlogSigThresholder(sig_filter_limit));
nremoved_sigfilter += (options.end() - new_end);
options.erase(new_end,options.end());
}
int main(int argc, char * argv[])
{
int c;
const char* efile=0;
const char* ffile=0;
int pfe_index = 2;
while ((c = getopt(argc, argv, "cpf:e:i:n:l:")) != -1) {
switch (c) {
case 'e':
efile = optarg;
break;
case 'f':
ffile = optarg;
break;
case 'i': // index of pfe in phrase table
pfe_index = atoi(optarg);
break;
case 'n': // keep only the top n entries in phrase table sorted by p(f|e) (0=all)
pfe_filter_limit = atoi(optarg);
std::cerr << "P(f|e) filter limit: " << pfe_filter_limit << std::endl;
break;
case 'c':
print_cooc_counts = true;
break;
case 'p':
print_neglog_significance = true;
break;
case 'l':
std::cerr << "-l = " << optarg << "\n";
if (strcmp(optarg,"a+e") == 0) {
sig_filter_limit = ALPHA_PLUS_EPS;
} else if (strcmp(optarg,"a-e") == 0) {
sig_filter_limit = ALPHA_MINUS_EPS;
} else {
char *x;
sig_filter_limit = strtod(optarg, &x);
if (sig_filter_limit < 0.0) {
std::cerr << "Filter limit (-l) must be either 'a+e', 'a-e' or a real number >= 0.0\n";
usage();
}
}
break;
default:
usage();
}
}
if (sig_filter_limit == 0.0) pef_filter_only = true;
//-----------------------------------------------------------------------------
if (optind != argc || ((!efile || !ffile) && !pef_filter_only)) {
usage();
}
//load the indexed corpus with vocabulary(noVoc=false) and with offset(noOffset=false)
if (!pef_filter_only) {
e_sa.loadData_forSearch(efile, false, false);
f_sa.loadData_forSearch(ffile, false, false);
size_t elines = e_sa.returnTotalSentNumber();
size_t flines = f_sa.returnTotalSentNumber();
if (elines != flines) {
std::cerr << "Number of lines in e-corpus != number of lines in f-corpus!\n";
usage();
} else {
std::cerr << "Training corpus: " << elines << " lines\n";
num_lines = elines;
}
p_111 = -log(fisher_exact(1,1,1));
std::cerr << "\\alpha = " << p_111 << "\n";
if (sig_filter_limit == ALPHA_MINUS_EPS) {
sig_filter_limit = p_111 - 0.001;
} else if (sig_filter_limit == ALPHA_PLUS_EPS) {
sig_filter_limit = p_111 + 0.001;
}
std::cerr << "Sig filter threshold is = " << sig_filter_limit << "\n";
} else {
std::cerr << "Filtering using P(e|f) only. n=" << pfe_filter_limit << std::endl;
}
char tmpString[10000];
std::string prev = "";
std::vector<PTEntry*> options;
size_t pt_lines = 0;
while(!cin.eof()) {
cin.getline(tmpString,10000,'\n');
if(++pt_lines%10000==0) {
std::cerr << ".";
if(pt_lines%500000==0) std::cerr << "[n:"<<pt_lines<<"]\n";
}
if(strlen(tmpString)>0) {
PTEntry* pp = new PTEntry(tmpString, pfe_index);
if (prev != pp->f_phrase) {
prev = pp->f_phrase;
if (!options.empty()) { // always true after first line
compute_cooc_stats_and_filter(options);
}
for (std::vector<PTEntry*>::iterator i=options.begin(); i != options.end(); ++i) {
std::cout << **i << std::endl;
delete *i;
}
options.clear();
options.push_back(pp);
} else {
options.push_back(pp);
}
// for(int i=0;i<locations.size(); i++){
// cout<<"SentId="<<locations[i].sentIdInCorpus<<" Pos="<<(int)locations[i].posInSentInCorpus<<endl;
// }
}
}
compute_cooc_stats_and_filter(options);
for (std::vector<PTEntry*>::iterator i=options.begin(); i != options.end(); ++i) {
std::cout << **i << std::endl;
delete *i;
}
float pfefper = (100.0*(float)nremoved_pfefilter)/(float)pt_lines;
float sigfper = (100.0*(float)nremoved_sigfilter)/(float)pt_lines;
std::cerr << "\n\n------------------------------------------------------\n"
<< " unfiltered phrases pairs: " << pt_lines << "\n"
<< "\n"
<< " P(f|e) filter [first]: " << nremoved_pfefilter << " (" << pfefper << "%)\n"
<< " significance filter: " << nremoved_sigfilter << " (" << sigfper << "%)\n"
<< " TOTAL FILTERED: " << (nremoved_pfefilter + nremoved_sigfilter) << " (" << (sigfper + pfefper) << "%)\n"
<< "\n"
<< " FILTERED phrase pairs: " << (pt_lines - nremoved_pfefilter - nremoved_sigfilter) << " (" << (100.0-sigfper - pfefper) << "%)\n"
<< "------------------------------------------------------\n";
return 0;
}
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