sampling : rename penalty params + reduce size of "prev" vector

llama.h

@@ -565,10 +565,10 @@ extern "C" {
             struct llama_context * ctx,
           llama_token_data_array * candidates,
                const llama_token * last_tokens,
-                          size_t   last_tokens_size,
-                           float   repeat_penalty,
-                           float   alpha_frequency,
-                           float   alpha_presence);
+                          size_t   penalty_last_n,
+                           float   penalty_repeat,
+                           float   penalty_freq,
+                           float   penalty_present);
 
     /// @details Apply classifier-free guidance to the logits as described in academic paper "Stay on topic with Classifier-Free Guidance" https://arxiv.org/abs/2306.17806
     /// @param candidates A vector of `llama_token_data` containing the candidate tokens, the logits must be directly extracted from the original generation context without being sorted.