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#include <sstream>
#include <iostream>
#include <vector>
#include <limits>
#include <boost/program_options.hpp>
#include <boost/program_options/variables_map.hpp>
#include "filelib.h"
#include "stringlib.h"
#include "weights.h"
#include "hg_io.h"
#include "kbest.h"
#include "viterbi.h"
#include "ns.h"
#include "ns_docscorer.h"
using namespace std;
namespace po = boost::program_options;
void InitCommandLine(int argc, char** argv, po::variables_map* conf) {
po::options_description opts("Configuration options");
opts.add_options()
("reference,r",po::value<vector<string> >(), "[REQD] Reference translation (tokenized text)")
("weights,w",po::value<string>(), "[REQD] Weights files from current iterations")
("input,i",po::value<string>()->default_value("-"), "Input file to map (- is STDIN)")
("evaluation_metric,m",po::value<string>()->default_value("IBM_BLEU"), "Evaluation metric (ibm_bleu, koehn_bleu, nist_bleu, ter, meteor, etc.)")
("kbest_size,k",po::value<unsigned>()->default_value(500u), "Top k-hypotheses to extract")
("cccp_iterations,I", po::value<unsigned>()->default_value(10u), "CCCP iterations (T')")
("ssd_iterations,J", po::value<unsigned>()->default_value(5u), "Stochastic subgradient iterations (T'')")
("eta", po::value<double>()->default_value(1e-4), "Step size")
("regularization_strength,C", po::value<double>()->default_value(1.0), "L2 regularization strength")
("alpha,a", po::value<double>()->default_value(10.0), "Cost scale (alpha); alpha * [1-metric(y,y')]")
("help,h", "Help");
po::options_description dcmdline_options;
dcmdline_options.add(opts);
po::store(parse_command_line(argc, argv, dcmdline_options), *conf);
bool flag = false;
if (!conf->count("reference")) {
cerr << "Please specify one or more references using -r <REF.TXT>\n";
flag = true;
}
if (!conf->count("weights")) {
cerr << "Please specify weights using -w <WEIGHTS.TXT>\n";
flag = true;
}
if (flag || conf->count("help")) {
cerr << dcmdline_options << endl;
exit(1);
}
}
struct HypInfo {
HypInfo() : g(-100.0f) {}
HypInfo(const vector<WordID>& h,
const SparseVector<weight_t>& feats,
const SegmentEvaluator& scorer, const EvaluationMetric* metric) : hyp(h), x(feats) {
SufficientStats ss;
scorer.Evaluate(hyp, &ss);
g = metric->ComputeScore(ss);
}
vector<WordID> hyp;
float g;
SparseVector<weight_t> x;
};
void CostAugmentedSearch(const vector<HypInfo>& kbest,
const SparseVector<double>& w,
double alpha,
SparseVector<double>* fmap) {
unsigned best_i = 0;
double best = -numeric_limits<double>::infinity();
for (unsigned i = 0; i < kbest.size(); ++i) {
double s = kbest[i].x.dot(w) + alpha * kbest[i].g;
if (s > best) {
best = s;
best_i = i;
}
}
*fmap = kbest[best_i].x;
}
// runs lines 4--15 of rampion algorithm
int main(int argc, char** argv) {
po::variables_map conf;
InitCommandLine(argc, argv, &conf);
const string evaluation_metric = conf["evaluation_metric"].as<string>();
EvaluationMetric* metric = EvaluationMetric::Instance(evaluation_metric);
DocumentScorer ds(metric, conf["reference"].as<vector<string> >());
cerr << "Loaded " << ds.size() << " references for scoring with " << evaluation_metric << endl;
double goodsign = 1;
if (metric->IsErrorMetric()) goodsign = -goodsign;
double badsign = -goodsign;
Hypergraph hg;
string last_file;
ReadFile in_read(conf["input"].as<string>());
istream &in=*in_read.stream();
const unsigned kbest_size = conf["kbest_size"].as<unsigned>();
const unsigned tp = conf["cccp_iterations"].as<unsigned>();
const unsigned tpp = conf["ssd_iterations"].as<unsigned>();
const double eta = conf["eta"].as<double>();
const double reg = conf["regularization_strength"].as<double>();
const double alpha = conf["alpha"].as<double>();
SparseVector<weight_t> weights;
{
vector<weight_t> vweights;
const string weightsf = conf["weights"].as<string>();
Weights::InitFromFile(weightsf, &vweights);
Weights::InitSparseVector(vweights, &weights);
}
string line, file;
vector<vector<HypInfo> > kis;
cerr << "Loading hypergraphs...\n";
while(getline(in, line)) {
istringstream is(line);
int sent_id;
kis.resize(kis.size() + 1);
vector<HypInfo>& curkbest = kis.back();
is >> file >> sent_id;
ReadFile rf(file);
HypergraphIO::ReadFromJSON(rf.stream(), &hg);
hg.Reweight(weights);
KBest::KBestDerivations<vector<WordID>, ESentenceTraversal> kbest(hg, kbest_size);
for (int i = 0; i < kbest_size; ++i) {
const KBest::KBestDerivations<vector<WordID>, ESentenceTraversal>::Derivation* d =
kbest.LazyKthBest(hg.nodes_.size() - 1, i);
if (!d) break;
curkbest.push_back(HypInfo(d->yield, d->feature_values, *ds[sent_id], metric));
}
}
cerr << "Hypergraphs loaded.\n";
vector<SparseVector<weight_t> > goals(kis.size()); // f(x_i,y+,h+)
SparseVector<weight_t> fear; // f(x,y-,h-)
for (unsigned iterp = 1; iterp <= tp; ++iterp) {
cerr << "CCCP Iteration " << iterp << endl;
for (int i = 0; i < goals.size(); ++i)
CostAugmentedSearch(kis[i], weights, goodsign * alpha, &goals[i]);
for (unsigned iterpp = 1; iterpp <= tpp; ++iterpp) {
cerr << " SSD Iteration " << iterpp << endl;
for (int i = 0; i < goals.size(); ++i) {
CostAugmentedSearch(kis[i], weights, badsign * alpha, &fear);
weights -= weights * (eta * reg / goals.size());
weights += (goals[i] - fear) * eta;
}
}
}
vector<weight_t> w;
weights.init_vector(&w);
Weights::WriteToFile("-", w);
return 0;
}
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