perplexity.cpp : fix hellaswag handling of prepended spaces

Author: klosax

examples/perplexity/perplexity.cpp

@@ -462,7 +462,13 @@ void hellaswag_score(llama_context * ctx, const gpt_params & params) {
         for (size_t ending_idx = 1; ending_idx < 4; ending_idx++) {
 
             // Tokenize the query
-            query_embd = ::llama_tokenize(ctx, hs_data[task_idx].ending[ending_idx], false);
+            // SPM tokenizer: Do not tokenize the starting space in the ending since it is always added by the tokenizer
+            if (is_spm) {
+                query_embd = ::llama_tokenize(ctx, hs_data[task_idx].ending[ending_idx].substr(1,hs_data[task_idx].ending[ending_idx].size()-1), false);
+            } else {
+                query_embd = ::llama_tokenize(ctx, hs_data[task_idx].ending[ending_idx], false);
+            }
+
             query_size = query_embd.size();
 
             // Stop if query wont fit the ctx window
@@ -505,6 +511,14 @@ void hellaswag_score(llama_context * ctx, const gpt_params & params) {
 //                task_idx,ending_idx,whole_size,context_size, hs_data[task_idx].ending_logprob_count[ending_idx], hs_data[task_idx].ending_logprob[ending_idx] );
         }
 
+        // TODO: Temporary check for NaNs until Falcon MMQ is solved
+        for (size_t j = 0; j < 4; j++) {
+            if (std::isnan(hs_data[task_idx].ending_logprob[j])) {
+                printf("NAN in task, %zu ending %zu\n",task_idx, j);
+                return;
+            }
+        }
+
         // Find the ending with maximum logprob
         size_t ending_logprob_max_idx = 0;
         double ending_logprob_max_val = hs_data[task_idx].ending_logprob[0];