TensorMap class added (for future use)

Author: Sergio0694

NeuralNetwork.NET/Helpers/TensorMap.cs

@@ -0,0 +1,104 @@
+using JetBrains.Annotations;
+using NeuralNetworkNET.APIs.Interfaces;
+using NeuralNetworkNET.APIs.Structs;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace NeuralNetworkNET.Helpers
+{
+    /// <summary>
+    /// A simple map that stores references to <see cref="Tensor"/> instances while training or using a network
+    /// </summary>
+    internal sealed class TensorMap : IDisposable
+    {
+        #region IDisposable
+
+        ~TensorMap() => Dispose();
+
+        /// <inheritdoc/>
+        void IDisposable.Dispose()
+        {
+            GC.SuppressFinalize(this);
+            Dispose();
+        }
+
+        // Frees the allocated tensors
+        private void Dispose()
+        {
+            foreach (Tensor tensor in new[] { ActivityMap, ActivationMap, DeltaMap }.SelectMany(d => d.Values))
+                tensor.Free();
+            ActivityMap.Clear();
+            ActivationMap.Clear();
+            DeltaMap.Clear();
+        }
+
+        #endregion
+
+        // The Z tensors
+        [NotNull]
+        private readonly IDictionary<INetworkLayer, Tensor> ActivityMap = new Dictionary<INetworkLayer, Tensor>();
+
+        // The A tensors
+        [NotNull]
+        private readonly IDictionary<INetworkLayer, Tensor> ActivationMap = new Dictionary<INetworkLayer, Tensor>();
+
+        // The dy tensors
+        [NotNull]
+        private readonly IDictionary<INetworkLayer, Tensor> DeltaMap = new Dictionary<INetworkLayer, Tensor>();
+
+        /// <summary>
+        /// Gets or sets a <see cref="Tensor"/> for the given network layer and data type
+        /// </summary>
+        /// <param name="layer">The source <see cref="INetworkLayer"/> instance for the target <see cref="Tensor"/></param>
+        /// <param name="type">The <see cref="TensorType"/> value for the target <see cref="Tensor"/></param>
+        public Tensor this[INetworkLayer layer, TensorType type]
+        {
+            [Pure]
+            get
+            {
+                switch (type)
+                {
+                    case TensorType.Activity: return ActivityMap[layer];
+                    case TensorType.Activation: return ActivationMap[layer];
+                    case TensorType.Delta: return DeltaMap[layer];
+                    default: throw new ArgumentOutOfRangeException(nameof(type), "Invalid data type requested");
+                }
+            }
+            set
+            {
+                IDictionary<INetworkLayer, Tensor> target;
+                switch (type)
+                {
+                    case TensorType.Activity: target = ActivityMap; break;
+                    case TensorType.Activation: target = ActivationMap; break;
+                    case TensorType.Delta: target = DeltaMap; break;
+                    default: throw new ArgumentOutOfRangeException(nameof(type), "Invalid data type requested");
+                }
+                if (target.TryGetValue(layer, out Tensor old)) old.Free();
+                target[layer] = value;
+            }
+        }
+    }
+
+    /// <summary>
+    /// Indicates the type of any given <see cref="Tensor"/>
+    /// </summary>
+    internal enum TensorType
+    {
+        /// <summary>
+        /// The activity of a network layer, the output before the activation function
+        /// </summary>
+        Activity,
+
+        /// <summary>
+        /// The activation of a network layer, the output with the activation function applied to it
+        /// </summary>
+        Activation,
+
+        /// <summary>
+        /// The error delta for the outputs of a given network layer
+        /// </summary>
+        Delta
+    }
+}