Array.Reshape(param int[])で次元を変えられる拡張メソッド

ArrayExtension.cs

    internal static class ArrayExtension
    {
        [SuppressUnmanagedCodeSecurity]
        [DllImport("kernel32.dll", EntryPoint = "CopyMemory", SetLastError = false)]
        public static extern void CopyMemory(IntPtr dest, IntPtr src, int count);

        public static Array Reshape(this Array array, params int[] shape)
        {
            Array result = Array.CreateInstance(array.GetType().GetElementType(), shape);

#if DEBUG
            if (array.Length != result.Length)throw new Exception();
#endif

            GCHandle source = GCHandle.Alloc(array, GCHandleType.Pinned);
            GCHandle dest = GCHandle.Alloc(result, GCHandleType.Pinned);

            CopyMemory(dest.AddrOfPinnedObject(), source.AddrOfPinnedObject(), Marshal.SizeOf(array.GetType().GetElementType()) * array.Length);

            dest.Free();
            source.Free();

            return result;
        }
        
        public static Array ToNdArray<T>(this IEnumerable<T> iEnum, params int[] shape)
        {
            Array array = iEnum.ToArray();
            Array result = Array.CreateInstance(array.GetType().GetElementType(), shape);

#if DEBUG
            if (array.Length != result.Length) throw new Exception();
#endif

            GCHandle source = GCHandle.Alloc(array, GCHandleType.Pinned);
            GCHandle dest = GCHandle.Alloc(result, GCHandleType.Pinned);

            CopyMemory(dest.AddrOfPinnedObject(), source.AddrOfPinnedObject(), Marshal.SizeOf(array.GetType().GetElementType()) * array.Length);

            dest.Free();
            source.Free();

            return result;
        }
    }