Moved `Eval` out of `Utils` and into `SafeLLamaContextHandle`

LLama/LLamaModel.cs

@@ -335,7 +335,7 @@ namespace LLama
                     n_eval = Params.BatchSize;
                 }
 
-                if(Utils.Eval(_ctx, tokens, i, n_eval, pastTokensCount, Params.Threads) != 0)
+                if (!_ctx.Eval(tokens.AsMemory(i, n_eval), pastTokensCount, Params.Threads))
                 {
                     _logger?.Log(nameof(LLamaModel), "Failed to eval.", ILLamaLogger.LogLevel.Error);
                     throw new RuntimeError("Failed to eval.");

LLama/LLamaStatelessExecutor.cs

@@ -31,7 +31,7 @@ namespace LLama
             _model = model;
             
             var tokens = model.Tokenize(" ", true).ToArray();
-            Utils.Eval(_model.NativeHandle, tokens, 0, tokens.Length, 0, _model.Params.Threads);
+            _model.NativeHandle.Eval(tokens.AsMemory(0, tokens.Length), 0, _model.Params.Threads);
             _originalState = model.GetState();
         }
 
@@ -52,7 +52,7 @@ namespace LLama
             List<llama_token> tokens = _model.Tokenize(text, true).ToList();
             int n_prompt_tokens = tokens.Count;
 
-            Utils.Eval(_model.NativeHandle, tokens.ToArray(), 0, n_prompt_tokens, n_past, _model.Params.Threads);
+            _model.NativeHandle.Eval(tokens.ToArray().AsMemory(0, n_prompt_tokens), n_past, _model.Params.Threads);
 
             lastTokens.AddRange(tokens);
             n_past += n_prompt_tokens;

LLama/Native/NativeApi.cs

@@ -207,6 +207,17 @@ namespace LLama.Native
         [DllImport(libraryName, CallingConvention = CallingConvention.Cdecl)]
         public static extern int llama_eval(SafeLLamaContextHandle ctx, llama_token[] tokens, int n_tokens, int n_past, int n_threads);
 
+        /// <summary>
+        /// Run the llama inference to obtain the logits and probabilities for the next token.
+        /// tokens + n_tokens is the provided batch of new tokens to process
+        /// n_past is the number of tokens to use from previous eval calls
+        /// </summary>
+        /// <param name="ctx"></param>
+        /// <param name="tokens"></param>
+        /// <param name="n_tokens"></param>
+        /// <param name="n_past"></param>
+        /// <param name="n_threads"></param>
+        /// <returns>Returns 0 on success</returns>
         [DllImport(libraryName, EntryPoint = "llama_eval", CallingConvention = CallingConvention.Cdecl)]
         public static extern int llama_eval_with_pointer(SafeLLamaContextHandle ctx, llama_token* tokens, int n_tokens, int n_past, int n_threads);
 

LLama/Native/SafeLLamaContextHandle.cs

@@ -169,5 +169,21 @@ namespace LLama.Native
         {
             return ThrowIfDisposed().TokenToSpan(token);
         }
+
+        /// <summary>
+        /// Run the llama inference to obtain the logits and probabilities for the next token.
+        /// </summary>
+        /// <param name="tokens">The provided batch of new tokens to process</param>
+        /// <param name="n_past">the number of tokens to use from previous eval calls</param>
+        /// <param name="n_threads"></param>
+        /// <returns>Returns true on success</returns>
+        public bool Eval(Memory<int> tokens, int n_past, int n_threads)
+        {
+            using var pin = tokens.Pin();
+            unsafe
+            {
+                return NativeApi.llama_eval_with_pointer(this, (int*)pin.Pointer, tokens.Length, n_past, n_threads) == 0;
+            }
+        }
     }
 }

LLama/Utils.cs

@@ -43,14 +43,11 @@ namespace LLama
             return ctx.GetLogits();
         }
 
-        public static unsafe int Eval(SafeLLamaContextHandle ctx, llama_token[] tokens, int startIndex, int n_tokens, int n_past, int n_threads)
+        [Obsolete("Use SafeLLamaContextHandle Eval method instead")]
+        public static int Eval(SafeLLamaContextHandle ctx, llama_token[] tokens, int startIndex, int n_tokens, int n_past, int n_threads)
         {
-            int result;
-            fixed(llama_token* p = tokens)
-            {
-                result = NativeApi.llama_eval_with_pointer(ctx, p + startIndex, n_tokens, n_past, n_threads);
-            }
-            return result;
+            var slice = tokens.AsMemory().Slice(startIndex, n_tokens);
+            return ctx.Eval(slice, n_past, n_threads) ? 0 : 1;
         }
 
         [Obsolete("Use SafeLLamaContextHandle TokenToString method instead")]