double Eval::ComputeOneDocLLH(Document* doc, Row<int32_t>& doc_topic_counter)
{
if (doc->Size() == 0) return 0.0;
double one_doc_llh = LogGamma(Config::num_topics * Config::alpha)
- Config::num_topics * LogGamma(Config::alpha);
int32_t nonzero_num = 0;
doc_topic_counter.Clear();
doc->GetDocTopicVector(doc_topic_counter);
Row<int32_t>::iterator iter = doc_topic_counter.Iterator();
while (iter.HasNext())
{
one_doc_llh += LogGamma(iter.Value() + Config::alpha);
++nonzero_num;
iter.Next();
}
one_doc_llh += (Config::num_topics - nonzero_num)
* LogGamma(Config::alpha);
one_doc_llh -= LogGamma(doc->Size() +
Config::alpha * Config::num_topics);
return one_doc_llh;
}
