Some Span<T>.DangerousCreate calls removed

Author: Sergio0694

NeuralNetwork.NET/APIs/Structs/DatasetSample.cs

@@ -10,14 +10,14 @@ public readonly ref struct DatasetSample
         /// <summary>
         /// Gets the <see cref="Span{T}"/> referencing the current sample inputs
         /// </summary>
-        public Span<float> X { get; }
+        public ReadOnlySpan<float> X { get; }
 
         /// <summary>
         /// Gets the <see cref="Span{T}"/> referencing the current sample expected outputs
         /// </summary>
-        public Span<float> Y { get; }
+        public ReadOnlySpan<float> Y { get; }
 
-        internal DatasetSample(Span<float> x, Span<float> y)
+        internal DatasetSample(ReadOnlySpan<float> x, ReadOnlySpan<float> y)
         {
             X = x;
             Y = y;

NeuralNetwork.NET/Extensions/SpanExtensions.cs

@@ -82,12 +82,13 @@ public static unsafe int GetContentHashCode<T>(this Span<T> span) where T : unma
         /// </summary>
         /// <param name="m">The source matrix</param>
         /// <param name="row">The target row to return</param>
-        [Pure]
+        [Pure, NotNull]
         [CollectionAccess(CollectionAccessType.Read)]
-        public static Span<T> Slice<T>([NotNull] this T[,] m, int row) where T : struct
+        public static unsafe T[] Slice<T>([NotNull] this T[,] m, int row) where T : unmanaged
         {
             if (row < 0 || row > m.GetLength(0) - 1) throw new ArgumentOutOfRangeException(nameof(row), "The row index isn't valid");
-            return Span<T>.DangerousCreate(m, ref m[row, 0], m.GetLength(1));
+            int wm = m.GetLength(1);
+            fixed (T* p = m) return new Span<T>(p + row * wm, wm).ToArray();
         }
 
         #endregion

NeuralNetwork.NET/SupervisedLearning/Data/BatchesCollection.cs

@@ -105,8 +105,8 @@ public void Expand(params Func<float[], float[]>[] factories)
                     for (int i = 0; i < n; i++)
                     {
                         float[]
-                            x = b.X.Slice(i).ToArray(),
-                            y = b.Y.Slice(i).ToArray();
+                            x = b.X.Slice(i),
+                            y = b.Y.Slice(i);
                         yield return () => (x, y);
                         foreach (Func<float[], float[]> f in factories)
                             yield return () => (f(x), y);