summaryrefslogtreecommitdiff
path: root/gi/pyp-topics/src/pyp-topics.cc
blob: 3614fb229cb5c92b75e29541cad641ea4fce1e8f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
#include "timing.h"
#include "pyp-topics.hh"

//#include <boost/date_time/posix_time/posix_time_types.hpp>
void PYPTopics::sample_corpus(const Corpus& corpus, int samples,
                              int freq_cutoff_start, int freq_cutoff_end,
                              int freq_cutoff_interval) {
  Timer timer;

  if (!m_backoff.get()) {
    m_word_pyps.clear();
    m_word_pyps.push_back(PYPs());
  }

  std::cerr << "\n Training with " << m_word_pyps.size()-1 << " backoff level"
    << (m_word_pyps.size()==2 ? ":" : "s:") << std::endl;


  for (int i=0; i<(int)m_word_pyps.size(); ++i)
  {
    m_word_pyps.at(i).reserve(m_num_topics);
    for (int j=0; j<m_num_topics; ++j)
      m_word_pyps.at(i).push_back(new PYP<int>(0.5, 1.0, m_seed));
  }
  std::cerr << std::endl;

  m_document_pyps.reserve(corpus.num_documents());
  for (int j=0; j<corpus.num_documents(); ++j)
    m_document_pyps.push_back(new PYP<int>(0.5, 1.0, m_seed));

  m_topic_p0 = 1.0/m_num_topics;
  m_term_p0 = 1.0/corpus.num_types();
  m_backoff_p0 = 1.0/corpus.num_documents();

  std::cerr << " Documents: " << corpus.num_documents() << " Terms: "
    << corpus.num_types() << std::endl;

  int frequency_cutoff = freq_cutoff_start;
  std::cerr << " Context frequency cutoff set to " << frequency_cutoff << std::endl;

  timer.Reset();
  // Initialisation pass
  int document_id=0, topic_counter=0;
  for (Corpus::const_iterator corpusIt=corpus.begin();
       corpusIt != corpus.end(); ++corpusIt, ++document_id) {
    m_corpus_topics.push_back(DocumentTopics(corpusIt->size(), 0));

    int term_index=0;
    for (Document::const_iterator docIt=corpusIt->begin();
         docIt != corpusIt->end(); ++docIt, ++term_index) {
      topic_counter++;
      Term term = *docIt;

      // sample a new_topic
      //int new_topic = (topic_counter % m_num_topics);
      int freq = corpus.context_count(term);
      int new_topic = (freq > frequency_cutoff ? (document_id % m_num_topics) : -1);

      // add the new topic to the PYPs
      m_corpus_topics[document_id][term_index] = new_topic;
      if (freq > frequency_cutoff) {
        increment(term, new_topic);

        if (m_use_topic_pyp) {
          F p0 = m_topic_pyp.prob(new_topic, m_topic_p0);
          int table_delta = m_document_pyps[document_id].increment(new_topic, p0);
          if (table_delta)
            m_topic_pyp.increment(new_topic, m_topic_p0);
        }
        else m_document_pyps[document_id].increment(new_topic, m_topic_p0);
      }
    }
  }
  std::cerr << "  Initialized in " << timer.Elapsed() << " seconds\n";

  int* randomDocIndices = new int[corpus.num_documents()];
  for (int i = 0; i < corpus.num_documents(); ++i)
	  randomDocIndices[i] = i;

  if (num_jobs < max_threads)
    num_jobs = max_threads;
  int job_incr = (int) ( (float)m_document_pyps.size() / float(num_jobs) );

  // Sampling phase
  for (int curr_sample=0; curr_sample < samples; ++curr_sample) {
    if (freq_cutoff_interval > 0 && curr_sample != 1
        && curr_sample % freq_cutoff_interval == 1
        && frequency_cutoff > freq_cutoff_end) {
      frequency_cutoff--;
      std::cerr << "\n Context frequency cutoff set to " << frequency_cutoff << std::endl;
    }

    std::cerr << "\n  -- Sample " << curr_sample << " "; std::cerr.flush();

    // Randomize the corpus indexing array
    int tmp;
    for (int i = corpus.num_documents()-1; i > 0; --i)
    {
        //i+1 since j \in [0,i] but rnd() \in [0,1)
    	int j = (int)(rnd() * (i+1));
      assert(j >= 0 && j <= i);
     	tmp = randomDocIndices[i];
    	randomDocIndices[i] = randomDocIndices[j];
    	randomDocIndices[j] = tmp;
    }

    // for each document in the corpus
    int document_id;
    for (int i=0; i<corpus.num_documents(); ++i)
    {
    	document_id = randomDocIndices[i];

      // for each term in the document
      int term_index=0;
      Document::const_iterator docEnd = corpus.at(document_id).end();
      for (Document::const_iterator docIt=corpus.at(document_id).begin();
           docIt != docEnd; ++docIt, ++term_index) {
        Term term = *docIt;
        int freq = corpus.context_count(term);
        if (freq < frequency_cutoff)
          continue;

        // remove the prevous topic from the PYPs
        int current_topic = m_corpus_topics[document_id][term_index];
        // a negative label mean that term hasn't been sampled yet
        if (current_topic >= 0) {
          decrement(term, current_topic);

          int table_delta = m_document_pyps[document_id].decrement(current_topic);
          if (m_use_topic_pyp && table_delta < 0)
            m_topic_pyp.decrement(current_topic);
        }

        // sample a new_topic
        int new_topic = sample(document_id, term);

        // add the new topic to the PYPs
        m_corpus_topics[document_id][term_index] = new_topic;
        increment(term, new_topic);

        if (m_use_topic_pyp) {
          F p0 = m_topic_pyp.prob(new_topic, m_topic_p0);
          int table_delta = m_document_pyps[document_id].increment(new_topic, p0);
          if (table_delta)
            m_topic_pyp.increment(new_topic, m_topic_p0);
        }
        else m_document_pyps[document_id].increment(new_topic, m_topic_p0);
      }
      if (document_id && document_id % 10000 == 0) {
        std::cerr << "."; std::cerr.flush();
      }
    }

    if (curr_sample != 0 && curr_sample % 10 == 0) {
      std::cerr << " ||| time=" << (timer.Elapsed() / 10.0) << " sec/sample" << std::endl;
      timer.Reset();
      std::cerr << "     ... Resampling hyperparameters (";
      
      // resample the hyperparamters
      F log_p=0.0;
      if (max_threads == 1)
      { 
        std::cerr << "1 thread)" << std::endl; std::cerr.flush();
        log_p += hresample_topics();
        log_p += hresample_docs(0, m_document_pyps.size());
      }
      else
      { //parallelize
        std::cerr << max_threads << " threads, " << num_jobs << " jobs)" << std::endl; std::cerr.flush();
        
        WorkerPool<JobReturnsF, F> pool(max_threads); 
        int i=0, sz = m_document_pyps.size();
        //documents...
        while (i <= sz - 2*job_incr)
        {    
          JobReturnsF job = boost::bind(&PYPTopics::hresample_docs, this, i, i+job_incr);
          pool.addJob(job);
          i += job_incr;
        }
        //  do all remaining documents
        JobReturnsF job = boost::bind(&PYPTopics::hresample_docs, this, i,sz);
        pool.addJob(job);
        
        //topics...
        JobReturnsF topics_job = boost::bind(&PYPTopics::hresample_topics, this);
        pool.addJob(topics_job);

        log_p += pool.get_result(); //blocks

      }

      if (m_use_topic_pyp) {
        m_topic_pyp.resample_prior();
        log_p += m_topic_pyp.log_restaurant_prob();
      }

      std::cerr.precision(10);
      std::cerr << " ||| LLH=" << log_p << " ||| resampling time=" << timer.Elapsed() << " sec" << std::endl;
      timer.Reset();

      int k=0;
      std::cerr << "Topics distribution: ";
      std::cerr.precision(2);
      for (PYPs::iterator pypIt=m_word_pyps.front().begin();
           pypIt != m_word_pyps.front().end(); ++pypIt, ++k) {
        if (k % 5 == 0) std::cerr << std::endl << '\t';
        std::cerr << "<" << k << ":" << pypIt->num_customers() << ","
          << pypIt->num_types() << "," << m_topic_pyp.prob(k, m_topic_p0) << "> ";
      }
      std::cerr.precision(4);
      std::cerr << std::endl;
    }
  }
  delete [] randomDocIndices;
}

PYPTopics::F PYPTopics::hresample_docs(int start, int end)
{
  int resample_counter=0;
  F log_p = 0.0;
  assert(start >= 0);
  assert(end >= 0);
  assert(start <= end);
  for (int i=start; i < end; ++i)
  {
    m_document_pyps[i].resample_prior();
    log_p += m_document_pyps[i].log_restaurant_prob();
    if (resample_counter++ % 5000 == 0) {
      std::cerr << "."; std::cerr.flush();
    }
  }
  return log_p;
}

PYPTopics::F PYPTopics::hresample_topics()
{
  F log_p = 0.0;
  for (std::vector<PYPs>::iterator levelIt=m_word_pyps.begin();
      levelIt != m_word_pyps.end(); ++levelIt) {
    for (PYPs::iterator pypIt=levelIt->begin();
        pypIt != levelIt->end(); ++pypIt) {

      pypIt->resample_prior();
      log_p += pypIt->log_restaurant_prob();
    }
  }
  return log_p;
}

void PYPTopics::decrement(const Term& term, int topic, int level) {
  //std::cerr << "PYPTopics::decrement(" << term << "," << topic << "," << level << ")" << std::endl;
  m_word_pyps.at(level).at(topic).decrement(term);
  if (m_backoff.get()) {
    Term backoff_term = (*m_backoff)[term];
    if (!m_backoff->is_null(backoff_term))
      decrement(backoff_term, topic, level+1);
  }
}

void PYPTopics::increment(const Term& term, int topic, int level) {
  //std::cerr << "PYPTopics::increment(" << term << "," << topic << "," << level << ")" << std::endl;
  m_word_pyps.at(level).at(topic).increment(term, word_pyps_p0(term, topic, level));

  if (m_backoff.get()) {
    Term backoff_term = (*m_backoff)[term];
    if (!m_backoff->is_null(backoff_term))
      increment(backoff_term, topic, level+1);
  }
}

int PYPTopics::sample(const DocumentId& doc, const Term& term) {
  // First pass: collect probs
  F sum=0.0;
  std::vector<F> sums;
  for (int k=0; k<m_num_topics; ++k) {
    F p_w_k = prob(term, k);

    F topic_prob = m_topic_p0;
    if (m_use_topic_pyp) topic_prob = m_topic_pyp.prob(k, m_topic_p0);

    //F p_k_d = m_document_pyps[doc].prob(k, topic_prob);
    F p_k_d = m_document_pyps[doc].unnormalised_prob(k, topic_prob);

    sum += (p_w_k*p_k_d);
    sums.push_back(sum);
  }
  // Second pass: sample a topic
  F cutoff = rnd() * sum;
  for (int k=0; k<m_num_topics; ++k) {
    if (cutoff <= sums[k])
      return k;
  }
  assert(false);
}

PYPTopics::F PYPTopics::word_pyps_p0(const Term& term, int topic, int level) const {
  //for (int i=0; i<level+1; ++i) std::cerr << "  ";
  //std::cerr << "PYPTopics::word_pyps_p0(" << term << "," << topic << "," << level << ")" << std::endl;

  F p0 = m_term_p0;
  if (m_backoff.get()) {
    //static F fudge=m_backoff_p0; // TODO

    Term backoff_term = (*m_backoff)[term];
    if (!m_backoff->is_null(backoff_term)) {
      assert (level < m_backoff->order());
      p0 = (1.0/(double)m_backoff->terms_at_level(level))*prob(backoff_term, topic, level+1);
    }
    else
      p0 = m_term_p0;
  }
  //for (int i=0; i<level+1; ++i) std::cerr << "  ";
  //std::cerr << "PYPTopics::word_pyps_p0(" << term << "," << topic << "," << level << ") = " << p0 << std::endl;
  return p0;
}

PYPTopics::F PYPTopics::prob(const Term& term, int topic, int level) const {
  //for (int i=0; i<level+1; ++i) std::cerr << "  ";
  //std::cerr << "PYPTopics::prob(" << term << "," << topic << "," << level << " " << factor << ")" << std::endl;

  F p0 = word_pyps_p0(term, topic, level);
  F p_w_k = m_word_pyps.at(level).at(topic).prob(term, p0);

  //for (int i=0; i<level+1; ++i) std::cerr << "  ";
  //std::cerr << "PYPTopics::prob(" << term << "," << topic << "," << level << ") = " << p_w_k << std::endl;

  return p_w_k;
}

int PYPTopics::max_topic() const {
  if (!m_use_topic_pyp)
    return -1;

  F current_max=0.0;
  int current_topic=-1;
  for (int k=0; k<m_num_topics; ++k) {
    F prob = m_topic_pyp.prob(k, m_topic_p0);
    if (prob > current_max) {
      current_max = prob;
      current_topic = k;
    }
  }
  assert(current_topic >= 0);
  return current_topic;
}

std::pair<int,PYPTopics::F> PYPTopics::max(const DocumentId& doc) const {
  //std::cerr << "PYPTopics::max(" << doc << "," << term << ")" << std::endl;
  // collect probs
  F current_max=0.0;
  int current_topic=-1;
  for (int k=0; k<m_num_topics; ++k) {
    //F p_w_k = prob(term, k);

    F topic_prob = m_topic_p0;
    if (m_use_topic_pyp)
      topic_prob = m_topic_pyp.prob(k, m_topic_p0);

    F prob = 0;
    if (doc < 0) prob = topic_prob;
    else         prob = m_document_pyps[doc].prob(k, topic_prob);

    if (prob > current_max) {
      current_max = prob;
      current_topic = k;
    }
  }
  assert(current_topic >= 0);
  assert(current_max >= 0);
  return std::make_pair(current_topic, current_max);
}

std::pair<int,PYPTopics::F> PYPTopics::max(const DocumentId& doc, const Term& term) const {
  //std::cerr << "PYPTopics::max(" << doc << "," << term << ")" << std::endl;
  // collect probs
  F current_max=0.0;
  int current_topic=-1;
  for (int k=0; k<m_num_topics; ++k) {
    F p_w_k = prob(term, k);

    F topic_prob = m_topic_p0;
    if (m_use_topic_pyp)
      topic_prob = m_topic_pyp.prob(k, m_topic_p0);

    F p_k_d = 0;
    if (doc < 0) p_k_d = topic_prob;
    else         p_k_d = m_document_pyps[doc].prob(k, topic_prob);

    F prob = (p_w_k*p_k_d);
    if (prob > current_max) {
      current_max = prob;
      current_topic = k;
    }
  }
  assert(current_topic >= 0);
  assert(current_max >= 0);
  return std::make_pair(current_topic,current_max);
}

std::ostream& PYPTopics::print_document_topics(std::ostream& out) const {
  for (CorpusTopics::const_iterator corpusIt=m_corpus_topics.begin();
       corpusIt != m_corpus_topics.end(); ++corpusIt) {
    int term_index=0;
    for (DocumentTopics::const_iterator docIt=corpusIt->begin();
         docIt != corpusIt->end(); ++docIt, ++term_index) {
      if (term_index) out << " ";
      out << *docIt;
    }
    out << std::endl;
  }
  return out;
}

std::ostream& PYPTopics::print_topic_terms(std::ostream& out) const {
  for (PYPs::const_iterator pypsIt=m_word_pyps.front().begin();
       pypsIt != m_word_pyps.front().end(); ++pypsIt) {
    int term_index=0;
    for (PYP<int>::const_iterator termIt=pypsIt->begin();
         termIt != pypsIt->end(); ++termIt, ++term_index) {
      if (term_index) out << " ";
      out << termIt->first << ":" << termIt->second;
    }
    out << std::endl;
  }
  return out;
}