Add some additional Tensor APIs (#117739)

* Remove unnecessary usings from Tensor code

* Add the TensorMarshal class

* Fix the naming of various tensor create APIs to remove ambiguities

* Add support for directly getting a contiguous span from a tensor

* Update the compatibility supressions file for S.N.Tensors

* Add tests for the new APIs

* Fix some tests

* Ensure the test calls TryGetSpan

Author: tannergooding

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/ref/System.Numerics.Tensors.netcore.cs

@@ -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/CompatibilitySuppressions.xml

@@ -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.csproj

@@ -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/TensorPrimitives.Helpers.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/TensorPrimitives.Single.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/Common/TensorPrimitives.IBooleanUnaryOperator.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/Common/TensorPrimitives.IUnaryInputBinaryOutput.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
 {