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authorKenneth Heafield <github@kheafield.com>2012-10-22 12:07:20 +0100
committerKenneth Heafield <github@kheafield.com>2012-10-22 12:07:20 +0100
commit5f98fe5c4f2a2090eeb9d30c030305a70a8347d1 (patch)
tree9b6002f850e6dea1e3400c6b19bb31a9cdf3067f /training/fast_align.cc
parentcf9994131993b40be62e90e213b1e11e6b550143 (diff)
parent21825a09d97c2e0afd20512f306fb25fed55e529 (diff)
Merge remote branch 'upstream/master'
Conflicts: Jamroot bjam decoder/Jamfile decoder/cdec.cc dpmert/Jamfile jam-files/sanity.jam klm/lm/Jamfile klm/util/Jamfile mira/Jamfile
Diffstat (limited to 'training/fast_align.cc')
-rw-r--r--training/fast_align.cc281
1 files changed, 281 insertions, 0 deletions
diff --git a/training/fast_align.cc b/training/fast_align.cc
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+++ b/training/fast_align.cc
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+#include <iostream>
+#include <cmath>
+
+#include <boost/program_options.hpp>
+#include <boost/program_options/variables_map.hpp>
+
+#include "m.h"
+#include "corpus_tools.h"
+#include "stringlib.h"
+#include "filelib.h"
+#include "ttables.h"
+#include "tdict.h"
+
+namespace po = boost::program_options;
+using namespace std;
+
+bool InitCommandLine(int argc, char** argv, po::variables_map* conf) {
+ po::options_description opts("Configuration options");
+ opts.add_options()
+ ("input,i",po::value<string>(),"Parallel corpus input file")
+ ("reverse,r","Reverse estimation (swap source and target during training)")
+ ("iterations,I",po::value<unsigned>()->default_value(5),"Number of iterations of EM training")
+ //("bidir,b", "Run bidirectional alignment")
+ ("favor_diagonal,d", "Use a static alignment distribution that assigns higher probabilities to alignments near the diagonal")
+ ("prob_align_null", po::value<double>()->default_value(0.08), "When --favor_diagonal is set, what's the probability of a null alignment?")
+ ("diagonal_tension,T", po::value<double>()->default_value(4.0), "How sharp or flat around the diagonal is the alignment distribution (<1 = flat >1 = sharp)")
+ ("variational_bayes,v","Infer VB estimate of parameters under a symmetric Dirichlet prior")
+ ("alpha,a", po::value<double>()->default_value(0.01), "Hyperparameter for optional Dirichlet prior")
+ ("no_null_word,N","Do not generate from a null token")
+ ("output_parameters,p", "Write model parameters instead of alignments")
+ ("beam_threshold,t",po::value<double>()->default_value(-4),"When writing parameters, log_10 of beam threshold for writing parameter (-10000 to include everything, 0 max parameter only)")
+ ("hide_training_alignments,H", "Hide training alignments (only useful if you want to use -x option and just compute testset statistics)")
+ ("testset,x", po::value<string>(), "After training completes, compute the log likelihood of this set of sentence pairs under the learned model")
+ ("no_add_viterbi,V","When writing model parameters, do not add Viterbi alignment points (may generate a grammar where some training sentence pairs are unreachable)");
+ po::options_description clo("Command line options");
+ clo.add_options()
+ ("config", po::value<string>(), "Configuration file")
+ ("help,h", "Print this help message and exit");
+ po::options_description dconfig_options, dcmdline_options;
+ dconfig_options.add(opts);
+ dcmdline_options.add(opts).add(clo);
+
+ po::store(parse_command_line(argc, argv, dcmdline_options), *conf);
+ if (conf->count("config")) {
+ ifstream config((*conf)["config"].as<string>().c_str());
+ po::store(po::parse_config_file(config, dconfig_options), *conf);
+ }
+ po::notify(*conf);
+
+ if (conf->count("help") || conf->count("input") == 0) {
+ cerr << "Usage " << argv[0] << " [OPTIONS] -i corpus.fr-en\n";
+ cerr << dcmdline_options << endl;
+ return false;
+ }
+ return true;
+}
+
+int main(int argc, char** argv) {
+ po::variables_map conf;
+ if (!InitCommandLine(argc, argv, &conf)) return 1;
+ const string fname = conf["input"].as<string>();
+ const bool reverse = conf.count("reverse") > 0;
+ const int ITERATIONS = conf["iterations"].as<unsigned>();
+ const double BEAM_THRESHOLD = pow(10.0, conf["beam_threshold"].as<double>());
+ const bool use_null = (conf.count("no_null_word") == 0);
+ const WordID kNULL = TD::Convert("<eps>");
+ const bool add_viterbi = (conf.count("no_add_viterbi") == 0);
+ const bool variational_bayes = (conf.count("variational_bayes") > 0);
+ const bool write_alignments = (conf.count("output_parameters") == 0);
+ const double diagonal_tension = conf["diagonal_tension"].as<double>();
+ const double prob_align_null = conf["prob_align_null"].as<double>();
+ const bool hide_training_alignments = (conf.count("hide_training_alignments") > 0);
+ string testset;
+ if (conf.count("testset")) testset = conf["testset"].as<string>();
+ const double prob_align_not_null = 1.0 - prob_align_null;
+ const double alpha = conf["alpha"].as<double>();
+ const bool favor_diagonal = conf.count("favor_diagonal");
+ if (variational_bayes && alpha <= 0.0) {
+ cerr << "--alpha must be > 0\n";
+ return 1;
+ }
+
+ TTable s2t, t2s;
+ TTable::Word2Word2Double s2t_viterbi;
+ double tot_len_ratio = 0;
+ double mean_srclen_multiplier = 0;
+ vector<double> unnormed_a_i;
+ for (int iter = 0; iter < ITERATIONS; ++iter) {
+ const bool final_iteration = (iter == (ITERATIONS - 1));
+ cerr << "ITERATION " << (iter + 1) << (final_iteration ? " (FINAL)" : "") << endl;
+ ReadFile rf(fname);
+ istream& in = *rf.stream();
+ double likelihood = 0;
+ double denom = 0.0;
+ int lc = 0;
+ bool flag = false;
+ string line;
+ string ssrc, strg;
+ vector<WordID> src, trg;
+ while(true) {
+ getline(in, line);
+ if (!in) break;
+ ++lc;
+ if (lc % 1000 == 0) { cerr << '.'; flag = true; }
+ if (lc %50000 == 0) { cerr << " [" << lc << "]\n" << flush; flag = false; }
+ src.clear(); trg.clear();
+ CorpusTools::ReadLine(line, &src, &trg);
+ if (reverse) swap(src, trg);
+ if (src.size() == 0 || trg.size() == 0) {
+ cerr << "Error: " << lc << "\n" << line << endl;
+ return 1;
+ }
+ if (src.size() > unnormed_a_i.size())
+ unnormed_a_i.resize(src.size());
+ if (iter == 0)
+ tot_len_ratio += static_cast<double>(trg.size()) / static_cast<double>(src.size());
+ denom += trg.size();
+ vector<double> probs(src.size() + 1);
+ bool first_al = true; // used for write_alignments
+ for (int j = 0; j < trg.size(); ++j) {
+ const WordID& f_j = trg[j];
+ double sum = 0;
+ const double j_over_ts = double(j) / trg.size();
+ double prob_a_i = 1.0 / (src.size() + use_null); // uniform (model 1)
+ if (use_null) {
+ if (favor_diagonal) prob_a_i = prob_align_null;
+ probs[0] = s2t.prob(kNULL, f_j) * prob_a_i;
+ sum += probs[0];
+ }
+ double az = 0;
+ if (favor_diagonal) {
+ for (int ta = 0; ta < src.size(); ++ta) {
+ unnormed_a_i[ta] = exp(-fabs(double(ta) / src.size() - j_over_ts) * diagonal_tension);
+ az += unnormed_a_i[ta];
+ }
+ az /= prob_align_not_null;
+ }
+ for (int i = 1; i <= src.size(); ++i) {
+ if (favor_diagonal)
+ prob_a_i = unnormed_a_i[i-1] / az;
+ probs[i] = s2t.prob(src[i-1], f_j) * prob_a_i;
+ sum += probs[i];
+ }
+ if (final_iteration) {
+ if (add_viterbi || write_alignments) {
+ WordID max_i = 0;
+ double max_p = -1;
+ int max_index = -1;
+ if (use_null) {
+ max_i = kNULL;
+ max_index = 0;
+ max_p = probs[0];
+ }
+ for (int i = 1; i <= src.size(); ++i) {
+ if (probs[i] > max_p) {
+ max_index = i;
+ max_p = probs[i];
+ max_i = src[i-1];
+ }
+ }
+ if (!hide_training_alignments && write_alignments) {
+ if (max_index > 0) {
+ if (first_al) first_al = false; else cout << ' ';
+ if (reverse)
+ cout << j << '-' << (max_index - 1);
+ else
+ cout << (max_index - 1) << '-' << j;
+ }
+ }
+ s2t_viterbi[max_i][f_j] = 1.0;
+ }
+ } else {
+ if (use_null)
+ s2t.Increment(kNULL, f_j, probs[0] / sum);
+ for (int i = 1; i <= src.size(); ++i)
+ s2t.Increment(src[i-1], f_j, probs[i] / sum);
+ }
+ likelihood += log(sum);
+ }
+ if (write_alignments && final_iteration && !hide_training_alignments) cout << endl;
+ }
+
+ // log(e) = 1.0
+ double base2_likelihood = likelihood / log(2);
+
+ if (flag) { cerr << endl; }
+ if (iter == 0) {
+ mean_srclen_multiplier = tot_len_ratio / lc;
+ cerr << "expected target length = source length * " << mean_srclen_multiplier << endl;
+ }
+ cerr << " log_e likelihood: " << likelihood << endl;
+ cerr << " log_2 likelihood: " << base2_likelihood << endl;
+ cerr << " cross entropy: " << (-base2_likelihood / denom) << endl;
+ cerr << " perplexity: " << pow(2.0, -base2_likelihood / denom) << endl;
+ if (!final_iteration) {
+ if (variational_bayes)
+ s2t.NormalizeVB(alpha);
+ else
+ s2t.Normalize();
+ }
+ }
+ if (testset.size()) {
+ ReadFile rf(testset);
+ istream& in = *rf.stream();
+ int lc = 0;
+ double tlp = 0;
+ string line;
+ while (getline(in, line)) {
+ ++lc;
+ vector<WordID> src, trg;
+ CorpusTools::ReadLine(line, &src, &trg);
+ cout << TD::GetString(src) << " ||| " << TD::GetString(trg) << " |||";
+ if (reverse) swap(src, trg);
+ double log_prob = Md::log_poisson(trg.size(), 0.05 + src.size() * mean_srclen_multiplier);
+ if (src.size() > unnormed_a_i.size())
+ unnormed_a_i.resize(src.size());
+
+ // compute likelihood
+ for (int j = 0; j < trg.size(); ++j) {
+ const WordID& f_j = trg[j];
+ double sum = 0;
+ int a_j = 0;
+ double max_pat = 0;
+ const double j_over_ts = double(j) / trg.size();
+ double prob_a_i = 1.0 / (src.size() + use_null); // uniform (model 1)
+ if (use_null) {
+ if (favor_diagonal) prob_a_i = prob_align_null;
+ max_pat = s2t.prob(kNULL, f_j) * prob_a_i;
+ sum += max_pat;
+ }
+ double az = 0;
+ if (favor_diagonal) {
+ for (int ta = 0; ta < src.size(); ++ta) {
+ unnormed_a_i[ta] = exp(-fabs(double(ta) / src.size() - j_over_ts) * diagonal_tension);
+ az += unnormed_a_i[ta];
+ }
+ az /= prob_align_not_null;
+ }
+ for (int i = 1; i <= src.size(); ++i) {
+ if (favor_diagonal)
+ prob_a_i = unnormed_a_i[i-1] / az;
+ double pat = s2t.prob(src[i-1], f_j) * prob_a_i;
+ if (pat > max_pat) { max_pat = pat; a_j = i; }
+ sum += pat;
+ }
+ log_prob += log(sum);
+ if (write_alignments) {
+ if (a_j > 0) {
+ cout << ' ';
+ if (reverse)
+ cout << j << '-' << (a_j - 1);
+ else
+ cout << (a_j - 1) << '-' << j;
+ }
+ }
+ }
+ tlp += log_prob;
+ cout << " ||| " << log_prob << endl << flush;
+ } // loop over test set sentences
+ cerr << "TOTAL LOG PROB " << tlp << endl;
+ }
+
+ if (write_alignments) return 0;
+
+ for (TTable::Word2Word2Double::iterator ei = s2t.ttable.begin(); ei != s2t.ttable.end(); ++ei) {
+ const TTable::Word2Double& cpd = ei->second;
+ const TTable::Word2Double& vit = s2t_viterbi[ei->first];
+ const string& esym = TD::Convert(ei->first);
+ double max_p = -1;
+ for (TTable::Word2Double::const_iterator fi = cpd.begin(); fi != cpd.end(); ++fi)
+ if (fi->second > max_p) max_p = fi->second;
+ const double threshold = max_p * BEAM_THRESHOLD;
+ for (TTable::Word2Double::const_iterator fi = cpd.begin(); fi != cpd.end(); ++fi) {
+ if (fi->second > threshold || (vit.find(fi->first) != vit.end())) {
+ cout << esym << ' ' << TD::Convert(fi->first) << ' ' << log(fi->second) << endl;
+ }
+ }
+ }
+ return 0;
+}
+