Add some additional Tensor APIs

src/libraries/System.Numerics.Tensors/ref/System.Numerics.Tensors.net9.cs

@@ -49,16 +49,18 @@ void System.IDisposable.Dispose() { }
         System.Numerics.Tensors.ReadOnlyTensorSpan<T> System.Numerics.Tensors.IReadOnlyTensor<System.Numerics.Tensors.TensorSpan<T>, T>.AsReadOnlyTensorSpan(params scoped System.ReadOnlySpan<System.Buffers.NRange> ranges) { throw null; }
         System.Numerics.Tensors.ReadOnlyTensorDimensionSpan<T> System.Numerics.Tensors.IReadOnlyTensor<System.Numerics.Tensors.TensorSpan<T>, T>.GetDimensionSpan(int dimension) { throw null; }
         ref readonly T System.Numerics.Tensors.IReadOnlyTensor<System.Numerics.Tensors.TensorSpan<T>, T>.GetPinnableReference() { throw null; }
+        System.ReadOnlySpan<T> System.Numerics.Tensors.IReadOnlyTensor<System.Numerics.Tensors.TensorSpan<T>, T>.GetSpan(scoped System.ReadOnlySpan<nint> startIndexes, int length) { throw null; }
+        System.ReadOnlySpan<T> System.Numerics.Tensors.IReadOnlyTensor<System.Numerics.Tensors.TensorSpan<T>, T>.GetSpan(scoped System.ReadOnlySpan<System.Buffers.NIndex> startIndexes, int length) { throw null; }
         System.Numerics.Tensors.TensorSpan<T> System.Numerics.Tensors.IReadOnlyTensor<System.Numerics.Tensors.TensorSpan<T>, T>.ToDenseTensor() { throw null; }
 
         bool System.Numerics.Tensors.ITensor.IsReadOnly { get { throw null; } }
         object? System.Numerics.Tensors.ITensor.this[params scoped System.ReadOnlySpan<System.Buffers.NIndex> indexes] { get { throw null; } set { } }
         object? System.Numerics.Tensors.ITensor.this[params scoped System.ReadOnlySpan<nint> indexes] { get { throw null; } set { } }
         void System.Numerics.Tensors.ITensor.Fill(object value) { }
-        static System.Numerics.Tensors.TensorSpan<T> ITensor<TensorSpan<T>, T>.Create(scoped System.ReadOnlySpan<nint> lengths, bool pinned) { throw null; }
-        static System.Numerics.Tensors.TensorSpan<T> ITensor<TensorSpan<T>, T>.Create(scoped System.ReadOnlySpan<nint> lengths, scoped System.ReadOnlySpan<nint> strides, bool pinned) { throw null; }
-        static System.Numerics.Tensors.TensorSpan<T> ITensor<TensorSpan<T>, T>.CreateUninitialized(scoped System.ReadOnlySpan<nint> lengths, bool pinned) { throw null; }
-        static System.Numerics.Tensors.TensorSpan<T> ITensor<TensorSpan<T>, T>.CreateUninitialized(scoped System.ReadOnlySpan<nint> lengths, scoped System.ReadOnlySpan<nint> strides, bool pinned) { throw null; }
+        static System.Numerics.Tensors.TensorSpan<T> ITensor<TensorSpan<T>, T>.CreateFromShape(scoped System.ReadOnlySpan<nint> lengths, bool pinned) { throw null; }
+        static System.Numerics.Tensors.TensorSpan<T> ITensor<TensorSpan<T>, T>.CreateFromShape(scoped System.ReadOnlySpan<nint> lengths, scoped System.ReadOnlySpan<nint> strides, bool pinned) { throw null; }
+        static System.Numerics.Tensors.TensorSpan<T> ITensor<TensorSpan<T>, T>.CreateFromShapeUninitialized(scoped System.ReadOnlySpan<nint> lengths, bool pinned) { throw null; }
+        static System.Numerics.Tensors.TensorSpan<T> ITensor<TensorSpan<T>, T>.CreateFromShapeUninitialized(scoped System.ReadOnlySpan<nint> lengths, scoped System.ReadOnlySpan<nint> strides, bool pinned) { throw null; }
         System.Numerics.Tensors.TensorSpan<T> System.Numerics.Tensors.ITensor<System.Numerics.Tensors.TensorSpan<T>, T>.AsTensorSpan() { throw null; }
         System.Numerics.Tensors.TensorSpan<T> System.Numerics.Tensors.ITensor<System.Numerics.Tensors.TensorSpan<T>, T>.AsTensorSpan(params scoped System.ReadOnlySpan<nint> startIndexes) { throw null; }
         System.Numerics.Tensors.TensorSpan<T> System.Numerics.Tensors.ITensor<System.Numerics.Tensors.TensorSpan<T>, T>.AsTensorSpan(params scoped System.ReadOnlySpan<System.Buffers.NIndex> startIndexes) { throw null; }

src/libraries/System.Numerics.Tensors/src/System.Numerics.Tensors.csproj

@@ -171,6 +171,7 @@
     <Compile Include="System\Numerics\Tensors\netcore\TensorShape.cs" />
     <Compile Include="System\Numerics\Tensors\netcore\TensorSpan_1.cs" />
     <Compile Include="System\Numerics\Tensors\netcore\TensorSpanDebugView.cs" />
+    <Compile Include="System\Runtime\InteropServices\TensorMarshal.cs" />
   </ItemGroup>
 
   <ItemGroup Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))">

src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/TensorPrimitives.Helpers.cs

@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Diagnostics.CodeAnalysis;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;

src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/TensorPrimitives.Single.cs

@@ -1,9 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Runtime.CompilerServices;
-using System.Runtime.InteropServices;
-
 namespace System.Numerics.Tensors
 {
     /// <summary>Performs primitive tensor operations over spans of memory.</summary>

src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/Common/TensorPrimitives.IBooleanUnaryOperator.cs

@@ -5,7 +5,6 @@
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Runtime.Intrinsics;
-using static System.Numerics.Tensors.TensorPrimitives;
 
 namespace System.Numerics.Tensors
 {

src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/Common/TensorPrimitives.IUnaryInputBinaryOutput.cs

@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Runtime.Intrinsics;

src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/IReadOnlyTensor_1.cs

@@ -72,6 +72,21 @@ public interface IReadOnlyTensor<TSelf, T> : IReadOnlyTensor
         /// <remarks>This method is intended to support .NET compilers and is not intended to be called by user code.</remarks>
         ref readonly T GetPinnableReference();
 
+        /// <summary>Return a span that starts at the specified index and contains the specified number of items.</summary>
+        /// <param name="startIndexes">The index at which the span should start.</param>
+        /// <param name="length">The length for the span to return.</param>
+        /// <returns>A span that consists of <paramref name="length" /> elements from the current tensor starting at <paramref name="startIndexes" />.</returns>
+        /// <exception cref="ArgumentOutOfRangeException">
+        ///   <para><paramref name="startIndexes" /> does not contain <see cref="IReadOnlyTensor.Rank" /> elements.</para>
+        ///   -or-
+        ///   <para><paramref name="length" /> is negative, greater than <see cref="IReadOnlyTensor.FlattenedLength" />, or would cause the span to contain elements that should be skipped due to <see cref="IReadOnlyTensor.Strides" />.</para>
+        /// </exception>
+        /// <exception cref="IndexOutOfRangeException"><paramref name="startIndexes" /> is not a valid index into the tensor.</exception>
+        ReadOnlySpan<T> GetSpan(scoped ReadOnlySpan<nint> startIndexes, int length);
+
+        /// <inheritdoc cref="GetSpan(ReadOnlySpan{nint}, int)" />
+        ReadOnlySpan<T> GetSpan(scoped ReadOnlySpan<NIndex> startIndexes, int length);
+
         /// <summary>Forms a slice out of the current tensor that begins at a specified index.</summary>
         /// <param name="startIndexes">The indexes at which to begin the slice.</param>
         /// <returns>A tensor that consists of all elements of the current tensor from <paramref name="startIndexes" /> to the end of the tensor.</returns>
@@ -112,5 +127,17 @@ public interface IReadOnlyTensor<TSelf, T> : IReadOnlyTensor
         ///   <para>If the <paramref name="destination" /> length is shorter than the source, no items are copied and the method returns <c>false</c>.</para>
         /// </remarks>
         bool TryFlattenTo(scoped Span<T> destination);
+
+        /// <summary>Tries to return a span that starts at the specified index and contains the specified number of items.</summary>
+        /// <param name="startIndexes">The index at which the span should start.</param>
+        /// <param name="length">The desired length of the span to retrieve.</param>
+        /// <param name="span">On successful return, a span that consists of <paramref name="length" /> elements from the current tensor starting at <paramref name="startIndexes" />.</param>
+        /// <returns><c>true</c> if a span was successfully retrieved; otherwise, <c>false</c> which indicates <paramref name="length" /> was invalid.</returns>
+        /// <exception cref="ArgumentOutOfRangeException"><paramref name="startIndexes" /> does not contain <see cref="IReadOnlyTensor.Rank" /> elements.</exception>
+        /// <exception cref="IndexOutOfRangeException"><paramref name="startIndexes" /> is not a valid index into the tensor.</exception>
+        bool TryGetSpan(scoped ReadOnlySpan<nint> startIndexes, int length, out ReadOnlySpan<T> span);
+
+        /// <inheritdoc cref="TryGetSpan(ReadOnlySpan{nint}, int, out ReadOnlySpan{T})" />
+        bool TryGetSpan(scoped ReadOnlySpan<NIndex> startIndexes, int length, out ReadOnlySpan<T> span);
     }
 }

src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/ITensor.cs

@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Buffers;
-using System.Diagnostics.CodeAnalysis;
 
 namespace System.Numerics.Tensors
 {

src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/ITensor_1.cs

@@ -25,7 +25,7 @@ public interface ITensor<TSelf, T> : ITensor, IReadOnlyTensor<TSelf, T>
         ///   <para>If <paramref name="pinned"/> is true the underlying buffer is created permanently pinned, otherwise the underlying buffer is not pinned.</para>
         ///   <para>The underlying buffer is initialized to default values.</para>
         /// </remarks>
-        static abstract TSelf Create(scoped ReadOnlySpan<nint> lengths, bool pinned = false);
+        static abstract TSelf CreateFromShape(scoped ReadOnlySpan<nint> lengths, bool pinned = false);
 
         /// <summary>Creates a new tensor with the specified lengths and strides.</summary>
         /// <param name="lengths">The lengths of each dimension.</param>
@@ -35,7 +35,7 @@ public interface ITensor<TSelf, T> : ITensor, IReadOnlyTensor<TSelf, T>
         ///   <para>If <paramref name="pinned"/> is true the underlying buffer is created permanently pinned, otherwise the underlying buffer is not pinned.</para>
         ///   <para>The underlying buffer is initialized to default values.</para>
         /// </remarks>
-        static abstract TSelf Create(scoped ReadOnlySpan<nint> lengths, scoped ReadOnlySpan<nint> strides, bool pinned = false);
+        static abstract TSelf CreateFromShape(scoped ReadOnlySpan<nint> lengths, scoped ReadOnlySpan<nint> strides, bool pinned = false);
 
         /// <summary>Creates a new tensor with the specified lengths and strides.</summary>
         /// <param name="lengths">The lengths of each dimension.</param>
@@ -44,7 +44,7 @@ public interface ITensor<TSelf, T> : ITensor, IReadOnlyTensor<TSelf, T>
         ///   <para>If <paramref name="pinned"/> is true the underlying buffer is created permanently pinned, otherwise the underlying buffer is not pinned.</para>
         ///   <para>The underlying buffer is not initialized.</para>
         /// </remarks>
-        static abstract TSelf CreateUninitialized(scoped ReadOnlySpan<nint> lengths, bool pinned = false);
+        static abstract TSelf CreateFromShapeUninitialized(scoped ReadOnlySpan<nint> lengths, bool pinned = false);
 
         /// <summary>Creates a new tensor with the specified lengths and strides. If <paramref name="pinned"/> is true the underlying buffer is created permanently pinned, otherwise the underlying buffer is not pinned. The underlying buffer is not initialized.</summary>
         /// <param name="lengths">The lengths of each dimension.</param>
@@ -54,7 +54,7 @@ public interface ITensor<TSelf, T> : ITensor, IReadOnlyTensor<TSelf, T>
         ///   If <paramref name="pinned"/> is true the underlying buffer is created permanently pinned, otherwise the underlying buffer is not pinned.
         /// The underlying buffer is not initialized.
         /// </remarks>
-        static abstract TSelf CreateUninitialized(scoped ReadOnlySpan<nint> lengths, scoped ReadOnlySpan<nint> strides, bool pinned = false);
+        static abstract TSelf CreateFromShapeUninitialized(scoped ReadOnlySpan<nint> lengths, scoped ReadOnlySpan<nint> strides, bool pinned = false);
 
         /// <inheritdoc cref="IReadOnlyTensor{TSelf, T}.this[ReadOnlySpan{nint}]" />
         new ref T this[params scoped ReadOnlySpan<nint> indexes] { get; }
@@ -93,5 +93,17 @@ public interface ITensor<TSelf, T> : ITensor, IReadOnlyTensor<TSelf, T>
 
         /// <inheritdoc cref="IReadOnlyTensor{TSelf, T}.GetPinnableReference" />
         new ref T GetPinnableReference();
+
+        /// <inheritdoc cref="IReadOnlyTensor{TSelf, T}.GetSpan(ReadOnlySpan{nint}, int)" />
+        new Span<T> GetSpan(scoped ReadOnlySpan<nint> startIndexes, int length);
+
+        /// <inheritdoc cref="IReadOnlyTensor{TSelf, T}.GetSpan(ReadOnlySpan{NIndex}, int)" />
+        new Span<T> GetSpan(scoped ReadOnlySpan<NIndex> startIndexes, int length);
+
+        /// <inheritdoc cref="IReadOnlyTensor{TSelf, T}.TryGetSpan(ReadOnlySpan{nint}, int, out ReadOnlySpan{T})" />
+        bool TryGetSpan(scoped ReadOnlySpan<nint> startIndexes, int length, out Span<T> span);
+
+        /// <inheritdoc cref="IReadOnlyTensor{TSelf, T}.TryGetSpan(ReadOnlySpan{NIndex}, int, out ReadOnlySpan{T})" />
+        bool TryGetSpan(scoped ReadOnlySpan<NIndex> startIndexes, int length, out Span<T> span);
     }
 }

src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/ReadOnlyTensorDimensionSpan_1.cs

@@ -51,7 +51,7 @@ public ReadOnlyTensorSpan<T> this[nint index]
                     ThrowHelper.ThrowArgumentOutOfRangeException();
                 }
 
-                nint linearOffset = _tensor._shape.GetLinearOffset(index, _dimension);
+                nint linearOffset = _tensor._shape.GetLinearOffsetForDimension(index, _dimension);
                 return new ReadOnlyTensorSpan<T>(ref Unsafe.Add(ref _tensor._reference, linearOffset), _sliceShape);
             }
         }

src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/ReadOnlyTensorSpan_1.cs

@@ -238,15 +238,15 @@ public unsafe ReadOnlyTensorSpan(T* data, nint dataLength, scoped ReadOnlySpan<n
             _reference = ref Unsafe.AsRef<T>(data);
         }
 
-        internal ReadOnlyTensorSpan(ref T data, nint dataLength, scoped ReadOnlySpan<nint> lengths, scoped ReadOnlySpan<nint> strides, bool pinned)
+        internal ReadOnlyTensorSpan(ref readonly T data, nint dataLength, scoped ReadOnlySpan<nint> lengths, scoped ReadOnlySpan<nint> strides, bool pinned)
         {
-            _shape = TensorShape.Create(ref data, dataLength, lengths, strides, pinned);
-            _reference = ref data;
+            _shape = TensorShape.Create(in data, dataLength, lengths, strides, pinned);
+            _reference = ref Unsafe.AsRef(in data);
         }
 
-        internal ReadOnlyTensorSpan(ref T reference, scoped in TensorShape shape)
+        internal ReadOnlyTensorSpan(ref readonly T reference, scoped in TensorShape shape)
         {
-            _reference = ref reference;
+            _reference = ref Unsafe.AsRef(in reference);
             _shape = shape;
         }
 
@@ -382,6 +382,26 @@ public ref readonly T GetPinnableReference()
             return ref ret;
         }
 
+        /// <inheritdoc cref="IReadOnlyTensor{TSelf, T}.GetSpan(ReadOnlySpan{nint}, int)" />
+        public ReadOnlySpan<T> GetSpan(scoped ReadOnlySpan<nint> startIndexes, int length)
+        {
+            if (!TryGetSpan(startIndexes, length, out ReadOnlySpan<T> span))
+            {
+                ThrowHelper.ThrowArgumentOutOfRangeException();
+            }
+            return span;
+        }
+
+        /// <inheritdoc cref="IReadOnlyTensor{TSelf, T}.GetSpan(ReadOnlySpan{NIndex}, int)" />
+        public ReadOnlySpan<T> GetSpan(scoped ReadOnlySpan<NIndex> startIndexes, int length)
+        {
+            if (!TryGetSpan(startIndexes, length, out ReadOnlySpan<T> span))
+            {
+                ThrowHelper.ThrowArgumentOutOfRangeException();
+            }
+            return span;
+        }
+
         /// <inheritdoc cref="IReadOnlyTensor{TSelf, T}.Slice(ReadOnlySpan{nint})" />
         public ReadOnlyTensorSpan<T> Slice(params scoped ReadOnlySpan<nint> startIndexes)
         {
@@ -438,6 +458,38 @@ public bool TryFlattenTo(scoped Span<T> destination)
             return false;
         }
 
+        /// <inheritdoc cref="IReadOnlyTensor{TSelf, T}.TryGetSpan(ReadOnlySpan{nint}, int, out ReadOnlySpan{T})" />
+        public bool TryGetSpan(scoped ReadOnlySpan<nint> startIndexes, int length, out ReadOnlySpan<T> span)
+        {
+            // This validates that startIndexes is valid and will throw ArgumentOutOfRangeException or IndexOutOfRangeException if it is not.
+            nint longestContiguousLength = _shape.GetLongestContiguousLength<TensorShape.GetOffsetAndLengthForNInt, nint>(startIndexes, out nint linearOffset);
+
+            if ((length < 0) || (length > longestContiguousLength))
+            {
+                span = default;
+                return false;
+            }
+
+            span = MemoryMarshal.CreateReadOnlySpan(in Unsafe.Add(ref _reference, linearOffset), length);
+            return true;
+        }
+
+        /// <inheritdoc cref="IReadOnlyTensor{TSelf, T}.TryGetSpan(ReadOnlySpan{NIndex}, int, out ReadOnlySpan{T})" />
+        public bool TryGetSpan(scoped ReadOnlySpan<NIndex> startIndexes, int length, out ReadOnlySpan<T> span)
+        {
+            // This validates that startIndexes is valid and will throw ArgumentOutOfRangeException or IndexOutOfRangeException if it is not.
+            nint longestContiguousLength = _shape.GetLongestContiguousLength<TensorShape.GetOffsetAndLengthForNIndex, NIndex>(startIndexes, out nint linearOffset);
+
+            if ((length < 0) || (length > longestContiguousLength))
+            {
+                span = default;
+                return false;
+            }
+
+            span = MemoryMarshal.CreateReadOnlySpan(in Unsafe.Add(ref _reference, linearOffset), length);
+            return true;
+        }
+
 #if NET9_0_OR_GREATER
         //
         // IReadOnlyTensor
@@ -465,7 +517,7 @@ ReadOnlyTensorSpan<T> IReadOnlyTensor<ReadOnlyTensorSpan<T>, T>.ToDenseTensor()
 
             if (!IsDense)
             {
-                Tensor<T> tmp = Tensor.Create<T>(Lengths, IsPinned);
+                Tensor<T> tmp = Tensor.CreateFromShape<T>(Lengths, IsPinned);
                 CopyTo(tmp);
                 result = tmp;
             }