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#include <iostream>
#include <vector>
#include <map>
#include "timer.h"
#include "crp.h"
#include "sampler.h"
#include "tdict.h"
Dict TD::dict_;
std::string TD::empty = "";
std::string TD::space = " ";
const size_t MAX_DOC_LEN_CHARS = 1000000;
using namespace std;
void ShowTopWordsForTopic(const map<WordID, int>& counts) {
multimap<int, WordID> ms;
for (map<WordID,int>::const_iterator it = counts.begin(); it != counts.end(); ++it)
ms.insert(make_pair(it->second, it->first));
int cc = 0;
for (multimap<int, WordID>::reverse_iterator it = ms.rbegin(); it != ms.rend(); ++it) {
cerr << it->first << ':' << TD::Convert(it->second) << " ";
++cc;
if (cc==12) break;
}
cerr << endl;
}
int main(int argc, char** argv) {
if (argc != 3) {
cerr << "Usage: " << argv[0] << " num-classes num-samples\n";
return 1;
}
const int num_classes = atoi(argv[1]);
const int num_iterations = atoi(argv[2]);
const int burnin_size = num_iterations * 0.666;
if (num_classes < 2) {
cerr << "Must request more than 1 class\n";
return 1;
}
if (num_iterations < 5) {
cerr << "Must request more than 5 iterations\n";
return 1;
}
cerr << "CLASSES: " << num_classes << endl;
char* buf = new char[MAX_DOC_LEN_CHARS];
vector<vector<int> > wji; // w[j][i] - observed word i of doc j
vector<vector<int> > zji; // z[j][i] - topic assignment for word i of doc j
cerr << "READING DOCUMENTS\n";
while(cin) {
cin.getline(buf, MAX_DOC_LEN_CHARS);
if (buf[0] == 0) continue;
wji.push_back(vector<WordID>());
TD::ConvertSentence(buf, &wji.back());
}
cerr << "READ " << wji.size() << " DOCUMENTS\n";
MT19937 rng;
cerr << "INITIALIZING RANDOM TOPIC ASSIGNMENTS\n";
zji.resize(wji.size());
double beta = 0.01;
double alpha = 0.001;
vector<CRP<int> > dr(zji.size(), CRP<int>(beta)); // dr[i] describes the probability of using a topic in document i
vector<CRP<int> > wr(num_classes, CRP<int>(alpha)); // wr[k] describes the probability of generating a word in topic k
int random_topic = rng.next() * num_classes;
for (int j = 0; j < zji.size(); ++j) {
const size_t num_words = wji[j].size();
vector<int>& zj = zji[j];
const vector<int>& wj = wji[j];
zj.resize(num_words);
for (int i = 0; i < num_words; ++i) {
if (random_topic == num_classes) { --random_topic; }
zj[i] = random_topic;
const int word = wj[i];
dr[j].increment(random_topic);
wr[random_topic].increment(word);
}
}
cerr << "SAMPLING\n";
vector<map<WordID, int> > t2w(num_classes);
Timer timer;
SampleSet ss;
ss.resize(num_classes);
double total_time = 0;
for (int iter = 0; iter < num_iterations; ++iter) {
cerr << '.';
if (iter && iter % 10 == 0) {
total_time += timer.Elapsed();
timer.Reset();
prob_t lh = prob_t::One();
for (int j = 0; j < zji.size(); ++j) {
const size_t num_words = wji[j].size();
vector<int>& zj = zji[j];
const vector<int>& wj = wji[j];
for (int i = 0; i < num_words; ++i) {
const int word = wj[i];
const int cur_topic = zj[i];
lh *= dr[j].prob(cur_topic);
lh *= wr[cur_topic].prob(word);
if (iter > burnin_size) {
++t2w[cur_topic][word];
}
}
}
if (iter && iter % 40 == 0) { cerr << " [ITER=" << iter << " SEC/SAMPLE=" << (total_time / 40) << " LLH=" << log(lh) << "]\n"; total_time=0; }
//cerr << "ITERATION " << iter << " LOG LIKELIHOOD: " << log(lh) << endl;
}
for (int j = 0; j < zji.size(); ++j) {
const size_t num_words = wji[j].size();
vector<int>& zj = zji[j];
const vector<int>& wj = wji[j];
for (int i = 0; i < num_words; ++i) {
const int word = wj[i];
const int cur_topic = zj[i];
dr[j].decrement(cur_topic);
wr[cur_topic].decrement(word);
for (int k = 0; k < num_classes; ++k) {
ss[k]= dr[j].prob(k) * wr[k].prob(word);
}
const int new_topic = rng.SelectSample(ss);
dr[j].increment(new_topic);
wr[new_topic].increment(word);
zj[i] = new_topic;
}
}
}
for (int i = 0; i < num_classes; ++i) {
cerr << "---------------------------------\n";
ShowTopWordsForTopic(t2w[i]);
}
return 0;
}
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