Update comments, more proper application

I see that numbers can go negative so a fix from a referenced commit

utils.cpp

@@ -391,8 +391,16 @@ gpt_vocab::id llama_sample_top_p(
     {
         const double scale = 1.0/temp;
         for (int i = 0; i < n_logits; ++i) {
+            // repetition penalty from CTRL paper (https://arxiv.org/abs/1909.05858)
+            // credit https://github.com/facebookresearch/llama/compare/main...shawwn:llama:main
             if ( std::find(last_n_tokens.begin(), last_n_tokens.end(), i) != last_n_tokens.end() ) {
-               logits_id.push_back(std::make_pair(logits[i]*scale*(1/repeat_penalty), i));
+                // if score < 0 then repetition penalty has to multiplied to reduce the previous token probability
+                if(logits[i] < 0.0) {
+                    logits_id.push_back(std::make_pair(logits[i]*scale*repeat_penalty, i));
+                } else {
+                    logits_id.push_back(std::make_pair(logits[i]*scale/repeat_penalty, i));
+                }                
+                
             } else {
                 logits_id.push_back(std::make_pair(logits[i]*scale, i));
             }