- Moved `GetLogits` into `SafeLLamaContextHandle`

- Added disposal check into `SafeLLamaContextHandle`

LLama/LLamaModel.cs

@@ -284,8 +284,8 @@ namespace LLama
             int repeatLastTokensCount = 64, float repeatPenalty = 1.1f, float alphaFrequency = .0f, float alphaPresence = .0f, 
             bool penalizeNL = true)
         {
-            var n_vocab = NativeApi.llama_n_vocab(_ctx);
-            var logits = Utils.GetLogits(_ctx, n_vocab);
+            var n_vocab = _ctx.VocabCount;
+            var logits = _ctx.GetLogits();
 
             // Apply params.logit_bias map
             if(logitBias is not null)

LLama/Native/NativeApi.cs

@@ -257,8 +257,8 @@ namespace LLama.Native
         /// <summary>
         /// Token logits obtained from the last call to llama_eval()
         /// The logits for the last token are stored in the last row
-        /// Can be mutated in order to change the probabilities of the next token
-        /// Rows: n_tokens
+        /// Can be mutated in order to change the probabilities of the next token.<br />
+        /// Rows: n_tokens<br />
         /// Cols: n_vocab
         /// </summary>
         /// <param name="ctx"></param>

LLama/Native/SafeLLamaContextHandle.cs

@@ -11,11 +11,29 @@ namespace LLama.Native
     public class SafeLLamaContextHandle
         : SafeLLamaHandleBase
     {
+        #region properties and fields
+        /// <summary>
+        /// Total number of tokens in vocabulary of this model
+        /// </summary>
+        public int VocabCount => ThrowIfDisposed().VocabCount;
+
+        /// <summary>
+        /// Total number of tokens in the context
+        /// </summary>
+        public int ContextSize => ThrowIfDisposed().ContextSize;
+
+        /// <summary>
+        /// Dimension of embedding vectors
+        /// </summary>
+        public int EmbeddingCount => ThrowIfDisposed().EmbeddingCount;
+
         /// <summary>
         /// This field guarantees that a reference to the model is held for as long as this handle is held
         /// </summary>
         private SafeLlamaModelHandle? _model;
+        #endregion
 
+        #region construction/destruction
         /// <summary>
         /// Create a new SafeLLamaContextHandle
         /// </summary>
@@ -44,6 +62,16 @@ namespace LLama.Native
             return true;
         }
 
+        private SafeLlamaModelHandle ThrowIfDisposed()
+        {
+            if (IsClosed)
+                throw new ObjectDisposedException("Cannot use this `SafeLLamaContextHandle` - it has been disposed");
+            if (_model == null || _model.IsClosed)
+                throw new ObjectDisposedException("Cannot use this `SafeLLamaContextHandle` - `SafeLlamaModelHandle` has been disposed");
+
+            return _model;
+        }
+
         /// <summary>
         /// Create a new llama_state for the given model
         /// </summary>
@@ -59,6 +87,7 @@ namespace LLama.Native
 
             return new(ctx_ptr, model);
         }
+        #endregion
 
         /// <summary>
         /// Convert the given text into tokens
@@ -70,6 +99,8 @@ namespace LLama.Native
         /// <exception cref="RuntimeError"></exception>
         public int[] Tokenize(string text, bool add_bos, Encoding encoding)
         {
+            ThrowIfDisposed();
+
             // Calculate number of bytes in string, this is a pessimistic estimate of token count. It can't
             // possibly be more than this.
             var count = encoding.GetByteCount(text) + (add_bos ? 1 : 0);
@@ -97,5 +128,25 @@ namespace LLama.Native
                 ArrayPool<int>.Shared.Return(temporaryArray);
             }
         }
+
+        /// <summary>
+        /// Token logits obtained from the last call to llama_eval()
+        /// The logits for the last token are stored in the last row
+        /// Can be mutated in order to change the probabilities of the next token.<br />
+        /// Rows: n_tokens<br />
+        /// Cols: n_vocab
+        /// </summary>
+        /// <param name="ctx"></param>
+        /// <returns></returns>
+        public Span<float> GetLogits()
+        {
+            var model = ThrowIfDisposed();
+
+            unsafe
+            {
+                var logits = NativeApi.llama_get_logits(this);
+                return new Span<float>(logits, model.VocabCount);
+            }
+        }
     }
 }

LLama/Native/SafeLlamaModelHandle.cs

@@ -13,17 +13,17 @@ namespace LLama.Native
         /// <summary>
         /// Total number of tokens in vocabulary of this model
         /// </summary>
-        public int VocabCount { get; set; }
+        public int VocabCount { get; }
 
         /// <summary>
         /// Total number of tokens in the context
         /// </summary>
-        public int ContextSize { get; set; }
+        public int ContextSize { get; }
 
         /// <summary>
         /// Dimension of embedding vectors
         /// </summary>
-        public int EmbeddingCount { get; set; }
+        public int EmbeddingCount { get; }
 
         internal SafeLlamaModelHandle(IntPtr handle)
             : base(handle)

LLama/Utils.cs

@@ -33,10 +33,13 @@ namespace LLama
             return ctx.Tokenize(text, add_bos, encoding);
         }
 
-        public static unsafe Span<float> GetLogits(SafeLLamaContextHandle ctx, int length)
+        [Obsolete("Use SafeLLamaContextHandle GetLogits method instead")]
+        public static Span<float> GetLogits(SafeLLamaContextHandle ctx, int length)
         {
-            var logits = NativeApi.llama_get_logits(ctx);
-            return new Span<float>(logits, length);
+            if (length != ctx.VocabCount)
+                throw new ArgumentException("length must be the VocabSize");
+
+            return ctx.GetLogits();
         }
 
         public static unsafe int Eval(SafeLLamaContextHandle ctx, llama_token[] tokens, int startIndex, int n_tokens, int n_past, int n_threads)