From de34b1493df93169c991a1828f951ca5abc00cae Mon Sep 17 00:00:00 2001 From: Chris Dyer Date: Mon, 5 Mar 2012 21:36:07 -0500 Subject: tie hyperparameters for translation distributions; support theta < 0 for PYPLM --- gi/pf/align-lexonly-pyp.cc | 13 ++++----- gi/pf/conditional_pseg.h | 68 ++++++++++++++++++++++++++++++++++++---------- gi/pf/pyp_lm.cc | 12 ++++---- 3 files changed, 66 insertions(+), 27 deletions(-) (limited to 'gi') diff --git a/gi/pf/align-lexonly-pyp.cc b/gi/pf/align-lexonly-pyp.cc index ac0590e0..13a3a487 100644 --- a/gi/pf/align-lexonly-pyp.cc +++ b/gi/pf/align-lexonly-pyp.cc @@ -68,14 +68,14 @@ struct AlignedSentencePair { struct HierarchicalWordBase { explicit HierarchicalWordBase(const unsigned vocab_e_size) : - base(prob_t::One()), r(1,1,1,1), u0(-log(vocab_e_size)), l(1,prob_t::One()), v(1, prob_t::Zero()) {} + base(prob_t::One()), r(1,1,1,1,0.66,50.0), u0(-log(vocab_e_size)), l(1,prob_t::One()), v(1, prob_t::Zero()) {} void ResampleHyperparameters(MT19937* rng) { r.resample_hyperparameters(rng); } inline double logp0(const vector& s) const { - return s.size() * u0; + return Md::log_poisson(s.size(), 7.5) + s.size() * u0; } // return p0 of rule.e_ @@ -106,7 +106,7 @@ struct HierarchicalWordBase { void Summary() const { cerr << "NUMBER OF CUSTOMERS: " << r.num_customers() << " (d=" << r.discount() << ",s=" << r.strength() << ')' << endl; for (MFCR<1,vector >::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; + cerr << " " << it->second.total_dish_count_ << " (on " << it->second.table_counts_.size() << " tables) " << TD::GetString(it->first) << endl; } prob_t base; @@ -167,10 +167,9 @@ struct BasicLexicalAlignment { } void ResampleHyperparemeters() { - cerr << " LLH_prev = " << Likelihood() << flush; tmodel.ResampleHyperparameters(&*prng); up0.ResampleHyperparameters(&*prng); - cerr << "\tLLH_post = " << Likelihood() << endl; + cerr << " (base d=" << up0.r.discount() << ",s=" << up0.r.strength() << ")\n"; } void ResampleCorpus(); @@ -218,7 +217,7 @@ void BasicLexicalAlignment::ResampleCorpus() { up0.Increment(r); } } - cerr << " LLH = " << tmodel.Likelihood() << endl; + cerr << " LLH = " << Likelihood() << endl; } void ExtractLetters(const set& v, vector >* l, set* letset = NULL) { @@ -311,7 +310,7 @@ int main(int argc, char** argv) { for (int i = 0; i < samples; ++i) { for (int j = 65; j < 67; ++j) Debug(corpus[j]); cerr << i << "\t" << x.tmodel.r.size() << "\t"; - if (i % 10 == 0) x.ResampleHyperparemeters(); + if (i % 7 == 6) x.ResampleHyperparemeters(); x.ResampleCorpus(); if (i > (samples / 5) && (i % 10 == 9)) for (int j = 0; j < corpus.size(); ++j) AddSample(&corpus[j]); } diff --git a/gi/pf/conditional_pseg.h b/gi/pf/conditional_pseg.h index ef73e332..8202778b 100644 --- a/gi/pf/conditional_pseg.h +++ b/gi/pf/conditional_pseg.h @@ -17,21 +17,66 @@ template struct MConditionalTranslationModel { explicit MConditionalTranslationModel(ConditionalBaseMeasure& rcp0) : - rp0(rcp0), lambdas(1, prob_t::One()), p0s(1) {} + rp0(rcp0), d(0.5), strength(1.0), lambdas(1, prob_t::One()), p0s(1) {} 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.discount() << ",s=" << it->second.strength() << ") --------------------------" << std::endl; for (MFCR<1,TRule>::const_iterator i2 = it->second.begin(); i2 != it->second.end(); ++i2) - std::cerr << " " << -1 << '\t' << i2->first << std::endl; + std::cerr << " " << i2->second.total_dish_count_ << '\t' << i2->first << std::endl; } } + 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, 10, 3) + Md::log_gamma_density(aa, 1, 1); + double llh = Md::log_beta_density(dd, 1, 1) + + Md::log_gamma_density(dd + aa, 1, 1); + typename std::tr1::unordered_map, MFCR<1,TRule>, boost::hash > >::const_iterator it; + for (it = r.begin(); it != r.end(); ++it) + llh += it->second.log_crp_prob(dd, aa); + return llh; + } + + struct DiscountResampler { + DiscountResampler(const MConditionalTranslationModel& m) : m_(m) {} + const MConditionalTranslationModel& m_; + double operator()(const double& proposed_discount) const { + return m_.log_likelihood(proposed_discount, m_.strength); + } + }; + + struct AlphaResampler { + AlphaResampler(const MConditionalTranslationModel& m) : m_(m) {} + const MConditionalTranslationModel& m_; + double operator()(const double& proposed_strength) const { + return m_.log_likelihood(m_.d, proposed_strength); + } + }; + void ResampleHyperparameters(MT19937* rng) { - for (RuleModelHash::iterator it = r.begin(); it != r.end(); ++it) - it->second.resample_hyperparameters(rng); - } + const unsigned nloop = 5; + const unsigned niterations = 10; + DiscountResampler dr(*this); + AlphaResampler ar(*this); + for (int iter = 0; iter < nloop; ++iter) { + strength = slice_sampler1d(ar, strength, *rng, -d + std::numeric_limits::min(), + std::numeric_limits::infinity(), 0.0, niterations, 100*niterations); + double min_discount = std::numeric_limits::min(); + if (strength < 0.0) min_discount -= strength; + d = slice_sampler1d(dr, d, *rng, min_discount, + 1.0, 0.0, niterations, 100*niterations); + } + strength = slice_sampler1d(ar, strength, *rng, -d, + std::numeric_limits::infinity(), 0.0, niterations, 100*niterations); + typename std::tr1::unordered_map, MFCR<1,TRule>, boost::hash > >::iterator it; + std::cerr << "MConditionalTranslationModel(d=" << d << ",s=" << strength << ") = " << log_likelihood(d, strength) << std::endl; + for (it = r.begin(); it != r.end(); ++it) { + it->second.set_discount(d); + it->second.set_strength(strength); + } + } int DecrementRule(const TRule& rule, MT19937* rng) { RuleModelHash::iterator it = r.find(rule.f_); @@ -46,7 +91,7 @@ struct MConditionalTranslationModel { int IncrementRule(const TRule& rule, MT19937* rng) { RuleModelHash::iterator it = r.find(rule.f_); if (it == r.end()) { - it = r.insert(make_pair(rule.f_, MFCR<1,TRule>(1.0, 1.0, 1.0, 1.0, 1e-9, 4.0))).first; + it = r.insert(make_pair(rule.f_, MFCR<1,TRule>(d, strength))).first; } p0s[0] = rp0(rule); TableCount delta = it->second.increment(rule, p0s.begin(), lambdas.begin(), rng); @@ -66,15 +111,7 @@ struct MConditionalTranslationModel { } prob_t Likelihood() const { - prob_t p = prob_t::One(); -#if 0 - for (RuleModelHash::const_iterator it = r.begin(); it != r.end(); ++it) { - prob_t q; q.logeq(it->second.log_crp_prob()); - p *= q; - for (CCRP_NoTable::const_iterator i2 = it->second.begin(); i2 != it->second.end(); ++i2) - p *= rp0(i2->first); - } -#endif + prob_t p; p.logeq(log_likelihood(d, strength)); return p; } @@ -83,6 +120,7 @@ struct MConditionalTranslationModel { MFCR<1, TRule>, boost::hash > > RuleModelHash; RuleModelHash r; + double d, strength; std::vector lambdas; mutable std::vector p0s; }; diff --git a/gi/pf/pyp_lm.cc b/gi/pf/pyp_lm.cc index 7ebada13..104f356b 100644 --- a/gi/pf/pyp_lm.cc +++ b/gi/pf/pyp_lm.cc @@ -18,7 +18,7 @@ // I use templates to handle the recursive formalation of the prior, so // the order of the model has to be specified here, at compile time: -#define kORDER 3 +#define kORDER 4 using namespace std; using namespace tr1; @@ -114,7 +114,7 @@ template struct PYPLM { if (aa <= -dd) return -std::numeric_limits::infinity(); //double llh = Md::log_beta_density(dd, 10, 3) + Md::log_gamma_density(aa, 1, 1); double llh = Md::log_beta_density(dd, discount_a, discount_b) + - Md::log_gamma_density(aa, strength_s, strength_r); + Md::log_gamma_density(aa + dd, strength_s, strength_r); 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); @@ -141,12 +141,14 @@ template struct PYPLM { DiscountResampler dr(*this); AlphaResampler ar(*this); for (int iter = 0; iter < nloop; ++iter) { - strength = slice_sampler1d(ar, strength, *rng, 0.0, + strength = slice_sampler1d(ar, strength, *rng, -d + std::numeric_limits::min(), std::numeric_limits::infinity(), 0.0, niterations, 100*niterations); - d = slice_sampler1d(dr, d, *rng, std::numeric_limits::min(), + double min_discount = std::numeric_limits::min(); + if (strength < 0.0) min_discount -= strength; + d = slice_sampler1d(dr, d, *rng, min_discount, 1.0, 0.0, niterations, 100*niterations); } - strength = slice_sampler1d(ar, strength, *rng, 0.0, + strength = slice_sampler1d(ar, strength, *rng, -d + std::numeric_limits::min(), std::numeric_limits::infinity(), 0.0, niterations, 100*niterations); typename unordered_map, CCRP, boost::hash > >::iterator it; cerr << "PYPLM<" << N << ">(d=" << d << ",a=" << strength << ") = " << log_likelihood(d, strength) << endl; -- cgit v1.2.3