From 2579dd24d3833823527e688196276c2fab381b37 Mon Sep 17 00:00:00 2001 From: Chris Dyer Date: Sat, 3 Mar 2012 17:16:58 -0500 Subject: pyp lm, fixed hyperparameters inference --- gi/pf/align-lexonly-pyp.cc | 2 +- gi/pf/align-lexonly.cc | 2 +- gi/pf/brat.cc | 2 +- gi/pf/conditional_pseg.h | 4 +-- gi/pf/learn_cfg.cc | 4 +-- gi/pf/pfbrat.cc | 2 +- gi/pf/pyp_lm.cc | 70 ++++++++++++++++++++++++++++++++++++++++++---- 7 files changed, 72 insertions(+), 14 deletions(-) (limited to 'gi/pf') diff --git a/gi/pf/align-lexonly-pyp.cc b/gi/pf/align-lexonly-pyp.cc index e24cb457..4ce7cf62 100644 --- a/gi/pf/align-lexonly-pyp.cc +++ b/gi/pf/align-lexonly-pyp.cc @@ -104,7 +104,7 @@ struct HierarchicalWordBase { } void Summary() const { - cerr << "NUMBER OF CUSTOMERS: " << r.num_customers() << " (d=" << r.d() << ",\\alpha=" << r.alpha() << ')' << endl; + cerr << "NUMBER OF CUSTOMERS: " << r.num_customers() << " (d=" << r.discount() << ",\\alpha=" << r.alpha() << ')' << endl; for (MFCR >::const_iterator it = r.begin(); it != r.end(); ++it) cerr << " " << it->second.total_dish_count_ << " (on " << it->second.table_counts_.size() << " tables)" << TD::GetString(it->first) << endl; } diff --git a/gi/pf/align-lexonly.cc b/gi/pf/align-lexonly.cc index 8c1d689f..dbc9dc07 100644 --- a/gi/pf/align-lexonly.cc +++ b/gi/pf/align-lexonly.cc @@ -105,7 +105,7 @@ struct HierarchicalWordBase { } void Summary() const { - cerr << "NUMBER OF CUSTOMERS: " << r.num_customers() << " (\\alpha=" << r.concentration() << ')' << endl; + cerr << "NUMBER OF CUSTOMERS: " << r.num_customers() << " (\\alpha=" << r.alpha() << ')' << endl; for (CCRP_NoTable >::const_iterator it = r.begin(); it != r.end(); ++it) cerr << " " << it->second << '\t' << TD::GetString(it->first) << endl; } diff --git a/gi/pf/brat.cc b/gi/pf/brat.cc index 7b60ef23..c2c52760 100644 --- a/gi/pf/brat.cc +++ b/gi/pf/brat.cc @@ -191,7 +191,7 @@ struct UniphraseLM { void ResampleHyperparameters(MT19937* rng) { phrases_.resample_hyperparameters(rng); gen_.resample_hyperparameters(rng); - cerr << " " << phrases_.concentration(); + cerr << " " << phrases_.alpha(); } CCRP_NoTable > phrases_; diff --git a/gi/pf/conditional_pseg.h b/gi/pf/conditional_pseg.h index 2e9e38fc..f9841cbf 100644 --- a/gi/pf/conditional_pseg.h +++ b/gi/pf/conditional_pseg.h @@ -22,7 +22,7 @@ struct MConditionalTranslationModel { void Summary() const { std::cerr << "Number of conditioning contexts: " << r.size() << std::endl; for (RuleModelHash::const_iterator it = r.begin(); it != r.end(); ++it) { - std::cerr << TD::GetString(it->first) << " \t(d=" << it->second.d() << ",\\alpha = " << it->second.alpha() << ") --------------------------" << std::endl; + std::cerr << TD::GetString(it->first) << " \t(d=" << it->second.discount() << ",\\alpha = " << it->second.alpha() << ") --------------------------" << std::endl; for (MFCR::const_iterator i2 = it->second.begin(); i2 != it->second.end(); ++i2) std::cerr << " " << -1 << '\t' << i2->first << std::endl; } @@ -95,7 +95,7 @@ struct ConditionalTranslationModel { void Summary() const { std::cerr << "Number of conditioning contexts: " << r.size() << std::endl; for (RuleModelHash::const_iterator it = r.begin(); it != r.end(); ++it) { - std::cerr << TD::GetString(it->first) << " \t(\\alpha = " << it->second.concentration() << ") --------------------------" << std::endl; + std::cerr << TD::GetString(it->first) << " \t(\\alpha = " << it->second.alpha() << ") --------------------------" << std::endl; for (CCRP_NoTable::const_iterator i2 = it->second.begin(); i2 != it->second.end(); ++i2) std::cerr << " " << i2->second << '\t' << i2->first << std::endl; } diff --git a/gi/pf/learn_cfg.cc b/gi/pf/learn_cfg.cc index b2ca029a..5b748311 100644 --- a/gi/pf/learn_cfg.cc +++ b/gi/pf/learn_cfg.cc @@ -183,9 +183,9 @@ struct HieroLMModel { nts[i].resample_hyperparameters(rng); if (kHIERARCHICAL_PRIOR) { q0.resample_hyperparameters(rng); - cerr << "[base d=" << q0.discount() << ", alpha=" << q0.discount() << "]"; + cerr << "[base d=" << q0.discount() << ", alpha=" << q0.alpha() << "]"; } - cerr << " d=" << nts[0].discount() << ", alpha=" << nts[0].concentration() << endl; + cerr << " d=" << nts[0].discount() << ", alpha=" << nts[0].alpha() << endl; } const BaseRuleModel base; diff --git a/gi/pf/pfbrat.cc b/gi/pf/pfbrat.cc index 7b60ef23..c2c52760 100644 --- a/gi/pf/pfbrat.cc +++ b/gi/pf/pfbrat.cc @@ -191,7 +191,7 @@ struct UniphraseLM { void ResampleHyperparameters(MT19937* rng) { phrases_.resample_hyperparameters(rng); gen_.resample_hyperparameters(rng); - cerr << " " << phrases_.concentration(); + cerr << " " << phrases_.alpha(); } CCRP_NoTable > phrases_; diff --git a/gi/pf/pyp_lm.cc b/gi/pf/pyp_lm.cc index 2837e33c..0d85536c 100644 --- a/gi/pf/pyp_lm.cc +++ b/gi/pf/pyp_lm.cc @@ -50,16 +50,19 @@ template struct PYPLM; // uniform base distribution template<> struct PYPLM<0> { - PYPLM(unsigned vs) : p0(1.0 / vs) {} - void increment(WordID w, const vector& context, MT19937* rng) const {} - void decrement(WordID w, const vector& context, MT19937* rng) const {} + PYPLM(unsigned vs) : p0(1.0 / vs), draws() {} + void increment(WordID w, const vector& context, MT19937* rng) { ++draws; } + void decrement(WordID w, const vector& context, MT19937* rng) { --draws; assert(draws >= 0); } double prob(WordID w, const vector& context) const { return p0; } + void resample_hyperparameters(MT19937* rng, const unsigned nloop, const unsigned niterations) {} + double log_likelihood() const { return draws * log(p0); } const double p0; + int draws; }; // represents an N-gram LM template struct PYPLM { - PYPLM(unsigned vs) : backoff(vs) {} + PYPLM(unsigned vs) : backoff(vs), d(0.8), alpha(1.0) {} void increment(WordID w, const vector& context, MT19937* rng) { const double bo = backoff.prob(w, context); static vector lookup(N-1); @@ -67,7 +70,7 @@ template struct PYPLM { lookup[i] = context[context.size() - 1 - i]; typename unordered_map, CCRP, boost::hash > >::iterator it = p.find(lookup); if (it == p.end()) - it = p.insert(make_pair(lookup, CCRP(1,1,1,1))).first; + it = p.insert(make_pair(lookup, CCRP(d,alpha))).first; if (it->second.increment(w, bo, rng)) backoff.increment(w, context, rng); } @@ -89,7 +92,58 @@ template struct PYPLM { if (it == p.end()) return bo; return it->second.prob(w, bo); } + + double log_likelihood() const { + return log_likelihood(d, alpha) + backoff.log_likelihood(); + } + + double log_likelihood(const double& dd, const double& aa) const { + if (aa <= -dd) return -std::numeric_limits::infinity(); + double llh = Md::log_beta_density(dd, 1, 1) + Md::log_gamma_density(aa, 1, 1); + typename unordered_map, CCRP, boost::hash > >::const_iterator it; + for (it = p.begin(); it != p.end(); ++it) + llh += it->second.log_crp_prob(dd, aa); + return llh; + } + + struct DiscountResampler { + DiscountResampler(const PYPLM& m) : m_(m) {} + const PYPLM& m_; + double operator()(const double& proposed_discount) const { + return m_.log_likelihood(proposed_discount, m_.alpha); + } + }; + + struct AlphaResampler { + AlphaResampler(const PYPLM& m) : m_(m) {} + const PYPLM& m_; + double operator()(const double& proposed_alpha) const { + return m_.log_likelihood(m_.d, proposed_alpha); + } + }; + + void resample_hyperparameters(MT19937* rng, const unsigned nloop = 5, const unsigned niterations = 10) { + DiscountResampler dr(*this); + AlphaResampler ar(*this); + for (int iter = 0; iter < nloop; ++iter) { + alpha = slice_sampler1d(ar, alpha, *rng, 0.0, + std::numeric_limits::infinity(), 0.0, niterations, 100*niterations); + d = slice_sampler1d(dr, d, *rng, std::numeric_limits::min(), + 1.0, 0.0, niterations, 100*niterations); + } + alpha = slice_sampler1d(ar, alpha, *rng, 0.0, + std::numeric_limits::infinity(), 0.0, niterations, 100*niterations); + typename unordered_map, CCRP, boost::hash > >::iterator it; + cerr << "PYPLM<" << N << ">(d=" << d << ",a=" << alpha << ") = " << log_likelihood(d, alpha) << endl; + for (it = p.begin(); it != p.end(); ++it) { + it->second.set_discount(d); + it->second.set_alpha(alpha); + } + backoff.resample_hyperparameters(rng, nloop, niterations); + } + PYPLM backoff; + double d, alpha; unordered_map, CCRP, boost::hash > > p; }; @@ -109,7 +163,7 @@ int main(int argc, char** argv) { cerr << "Reading corpus...\n"; CorpusTools::ReadFromFile(conf["input"].as(), &corpuse, &vocabe); cerr << "E-corpus size: " << corpuse.size() << " sentences\t (" << vocabe.size() << " word types)\n"; -#define kORDER 5 +#define kORDER 3 PYPLM lm(vocabe.size()); vector ctx(kORDER - 1, TD::Convert("")); int mci = corpuse.size() * 99 / 100; @@ -126,6 +180,10 @@ int main(int argc, char** argv) { if (SS > 0) lm.decrement(kEOS, ctx, &rng); lm.increment(kEOS, ctx, &rng); } + if (SS % 10 == 9) { + cerr << " [LLH=" << lm.log_likelihood() << "]" << endl; + if (SS % 20 == 19) lm.resample_hyperparameters(&rng); + } else { cerr << '.' << flush; } } double llh = 0; unsigned cnt = 0; -- cgit v1.2.3