diff options
Diffstat (limited to 'decoder/cdec.cc')
| -rw-r--r-- | decoder/cdec.cc | 49 |
1 files changed, 30 insertions, 19 deletions
diff --git a/decoder/cdec.cc b/decoder/cdec.cc index e3a2435d..bb29bafb 100644 --- a/decoder/cdec.cc +++ b/decoder/cdec.cc @@ -86,6 +86,8 @@ void InitCommandLine(int argc, char** argv, po::variables_map* conf) { ("show_expected_length", "Show the expected translation length under the model") ("show_partition,z", "Compute and show the partition (inside score)") ("show_cfg_search_space", "Show the search space as a CFG") + ("prelm_density_prune", po::value<double>(), "Applied to -LM forest just before final LM rescoring: keep no more than this many times the number of edges used in the best derivation tree (>=1.0)") + ("density_prune", po::value<double>(), "Keep no more than this many times the number of edges used in the best derivation tree (>=1.0)") ("prelm_beam_prune", po::value<double>(), "Prune paths from -LM forest before LM rescoring, keeping paths within exp(alpha>=0)") ("beam_prune", po::value<double>(), "Prune paths from +LM forest, keep paths within exp(alpha>=0)") ("scale_prune_srclen", "scale beams by the input length (in # of tokens; may not be what you want for lattices") @@ -241,7 +243,7 @@ static void ExtractRulesDedupe(const Hypergraph& hg, ostream* os) { void register_feature_functions(); -bool beam_param(po::variables_map const& conf,char const* name,double *val,bool scale_srclen=false,double srclen=1) +bool beam_param(po::variables_map const& conf,string const& name,double *val,bool scale_srclen=false,double srclen=1) { if (conf.count(name)) { *val=conf[name].as<double>()*(scale_srclen?srclen:1); @@ -263,6 +265,28 @@ bool prelm_weights_string(po::variables_map const& conf,string &s) return false; } +void maybe_prune(Hypergraph &forest,po::variables_map const& conf,string nbeam,string ndensity,string forestname,double srclen) { + double beam_prune,density_prune; + bool use_beam_prune=beam_param(conf,nbeam,&beam_prune,conf.count("scale_prune_srclen"),srclen); + bool use_density_prune=beam_param(conf,ndensity,&density_prune); + if (use_beam_prune || use_density_prune) { + double presize=forest.edges_.size(); + vector<bool> preserve_mask,*pm=0; + if (conf.count("csplit_preserve_full_word")) { + preserve_mask.resize(forest.edges_.size()); + preserve_mask[CompoundSplit::GetFullWordEdgeIndex(forest)] = true; + pm=&preserve_mask; + } + if (use_beam_prune) + forest.BeamPruneInsideOutside(1.0, false, beam_prune, pm); + if (use_density_prune) + forest.DensityPruneInsideOutside(1.0 ,false, density_prune, pm); + if (!forestname.empty()) forestname=" "+forestname; + cerr << viterbi_stats(forest," Pruned "+forestname+" forest",false,false); + cerr << " Pruned "<<forestname<<" forest portion of edges kept: "<<forest.edges_.size()/presize<<endl; + } +} + int main(int argc, char** argv) { global_ff_registry.reset(new FFRegistry); @@ -282,12 +306,11 @@ int main(int argc, char** argv) { const string formalism = LowercaseString(conf["formalism"].as<string>()); const bool csplit_preserve_full_word = conf.count("csplit_preserve_full_word"); if (csplit_preserve_full_word && - (formalism != "csplit" || !conf.count("beam_prune"))) { + (formalism != "csplit" || !(conf.count("beam_prune")||conf.count("density_prune")||conf.count("prelm_beam_prune")||conf.count("prelm_density_prune")))) { cerr << "--csplit_preserve_full_word should only be " - << "used with csplit AND --beam_prune!\n"; + << "used with csplit AND --*_prune!\n"; exit(1); } - const bool scale_prune_srclen=conf.count("scale_prune_srclen"); const bool csplit_output_plf = conf.count("csplit_output_plf"); if (csplit_output_plf && formalism != "csplit") { cerr << "--csplit_output_plf should only be used with csplit!\n"; @@ -477,13 +500,7 @@ int main(int argc, char** argv) { cerr << viterbi_stats(forest," prelm forest",true,show_tree_structure); } - double prelm_beam_prune; - if (beam_param(conf,"prelm_beam_prune",&prelm_beam_prune,scale_prune_srclen,srclen)) { - double presize=forest.edges_.size(); - forest.BeamPruneInsideOutside(1.0, false, prelm_beam_prune, NULL); - cerr << viterbi_stats(forest," Pruned -LM forest",false,false); - cerr << " Pruned -LM forest (beam="<<prelm_beam_prune<<") portion of edges kept: "<<forest.edges_.size()/presize<<endl; - } + maybe_prune(forest,conf,"prelm_beam_prune","prelm_density_prune","-LM",srclen); bool has_late_models = !late_models.empty(); if (has_late_models) { @@ -501,14 +518,8 @@ int main(int argc, char** argv) { forest.Reweight(feature_weights); cerr << viterbi_stats(forest," +LM forest",true,show_tree_structure); } - double beam_prune; - if (beam_param(conf,"beam_prune",&beam_prune,scale_prune_srclen,srclen)) { - vector<bool> preserve_mask(forest.edges_.size(), false); - if (csplit_preserve_full_word) - preserve_mask[CompoundSplit::GetFullWordEdgeIndex(forest)] = true; - forest.BeamPruneInsideOutside(1.0, false, beam_prune, &preserve_mask); - cerr << viterbi_stats(forest," Pruned forest",false,false); - } + + maybe_prune(forest,conf,"beam_prune","density_prune","+LM",srclen); if (conf.count("forest_output") && !has_ref) { ForestWriter writer(conf["forest_output"].as<string>(), sent_id); |