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#include "kgramstats.h"
#include <vector>
#include <iostream>
#include <cstdlib>
#include <algorithm>
// runs in O(t^2) time where t is the number of tokens in the input corpus
// We consider maxK to be fairly constant
kgramstats::kgramstats(string corpus, int maxK)
{
this->maxK = maxK;
vector<string> tokens;
int start = 0;
int end = 0;
while (end != string::npos)
{
end = corpus.find(" ", start);
string token = corpus.substr(start, (end == string::npos) ? string::npos : end - start);
if (token.compare(""))
{
tokens.push_back(token);
}
start = ((end > (string::npos - 1) ) ? string::npos : end + 1);
}
map<kgram, map<string, token_data*>* > tstats;
for (int k=0; k<=maxK; k++)
{
for (int i=0; i<(tokens.size() - k); i++)
{
kgram seq(tokens.begin()+i, tokens.begin()+i+k);
transform(seq.begin(), seq.end(), seq.begin(), canonize);
string f = tokens[i+k];
string canonical = canonize(f);
if (tstats[seq] == NULL)
{
tstats[seq] = new map<string, token_data*>();
}
if ((*tstats[seq])[canonical] == NULL)
{
(*tstats[seq])[canonical] = (token_data*) calloc(1, sizeof(token_data));
}
token_data* td = tstats[seq]->at(canonical);
td->token = new string(canonical);
td->all++;
if ((f.length() > 0) && (f[f.length()-1] == '.'))
{
td->period++;
}
if (std::find_if(f.begin(), f.end(), ::islower) == f.end())
{
td->uppercase++;
} else if (isupper(f[0]))
{
td->titlecase++;
}
}
}
stats = new map<kgram, map<int, token_data*>* >();
for (map<kgram, map<string, token_data*>* >::iterator it = tstats.begin(); it != tstats.end(); it++)
{
kgram klist = it->first;
map<string, token_data*>* probtable = it->second;
map<int, token_data*>* distribution = new map<int, token_data*>();
int max = 0;
for (map<string, token_data*>::iterator kt = probtable->begin(); kt != probtable->end(); kt++)
{
max += kt->second->all;
(*distribution)[max] = kt->second;
}
(*stats)[klist] = distribution;
}
}
void printKgram(kgram k)
{
for (kgram::iterator it = k.begin(); it != k.end(); it++)
{
cout << *it << " ";
}
}
// runs in O(n log t) time where n is the input number of sentences and t is the number of tokens in the input corpus
vector<string> kgramstats::randomSentence(int n)
{
vector<string> result;
list<string> cur;
for (int i=0; i<n; i++)
{
if ((rand() % (maxK - cur.size() + 1)) == 0)
{
for (int i=0; i<cur.size(); i++)
{
if ((rand() % 3) != 0)
{
cur.pop_front();
} else {
break;
}
}
}
map<int, token_data*> distribution = *(*stats)[cur];
int max = distribution.rbegin()->first;
int r = rand() % max;
token_data* next = distribution.upper_bound(r)->second;
string nextToken(*(next->token));
int casing = rand() % next->all;
int period = rand() % next->all;
if (casing < next->uppercase)
{
transform(nextToken.begin(), nextToken.end(), nextToken.begin(), ::toupper);
} else if ((casing - next->uppercase) < next->titlecase)
{
nextToken[0] = toupper(nextToken[0]);
}
if (period < next->period)
{
nextToken += ".";
}
if (cur.size() == maxK)
{
cur.pop_front();
}
/* DEBUG */
for (kgram::iterator it = cur.begin(); it != cur.end(); it++)
{
cout << *it << " ";
}
cout << "-> \"" << nextToken << "\" (" << next->all << "/" << max << ")" << endl;
cur.push_back(*(next->token));
result.push_back(nextToken);
}
return result;
}
std::string canonize(std::string f)
{
string canonical(f);
transform(canonical.begin(), canonical.end(), canonical.begin(), ::tolower);
if (canonical[canonical.length()-1] == '.')
{
canonical.resize(canonical.find('.'));
}
return canonical;
}
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