Stop using LINQ in Tensors (#109415)

stephentoub · web-flow · commit 52ae0e9fa470 · 2024-11-26T14:06:37.000-05:00
Using `IEnumerable&lt;T&gt;` and associated LINQ extensions for numerical processing is not appropriate at this level of the stack. The only remaining use is where the input provided by the user is already an `IEnumerable&lt;T&gt;` and `ToArray` is used to get the required `T[]`, which is fine.
diff --git a/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/ReadOnlyTensorSpan.cs b/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/ReadOnlyTensorSpan.cs
@@ -4,7 +4,6 @@
 using System.Buffers;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using EditorBrowsableAttribute = System.ComponentModel.EditorBrowsableAttribute;
@@ -141,7 +140,17 @@ public ReadOnlyTensorSpan(ReadOnlySpan<T> span, scoped ReadOnlySpan<nint> length
         /// have a rank of 1 and a length equal to the length of the provided <see cref="Array"/>.
         /// </summary>
         /// <param name="array">The target array.</param>
-        public ReadOnlyTensorSpan(Array? array) : this(array, ReadOnlySpan<int>.Empty, array == null ? [0] : (from dim in Enumerable.Range(0, array.Rank) select (nint)array.GetLength(dim)).ToArray(), []) { }
+        public ReadOnlyTensorSpan(Array? array) :
+            this(array,
+                 ReadOnlySpan<int>.Empty,
+                 array == null ?
+                    [0] :
+                    TensorSpanHelpers.FillLengths(array.Rank <= TensorShape.MaxInlineRank ?
+                        stackalloc nint[array.Rank] :
+                        new nint[array.Rank], array),
+                 [])
+        {
+        }
 
         /// <summary>
         /// Creates a new <see cref="ReadOnlyTensorSpan{T}"/> over the provided <see cref="Array"/> using the specified start offsets, lengths, and strides.
@@ -153,7 +162,11 @@ public ReadOnlyTensorSpan(Array? array) : this(array, ReadOnlySpan<int>.Empty, a
         public ReadOnlyTensorSpan(Array? array, scoped ReadOnlySpan<int> start, scoped ReadOnlySpan<nint> lengths, scoped ReadOnlySpan<nint> strides)
         {
             if (lengths.IsEmpty && array != null)
-                lengths = (from dim in Enumerable.Range(0, array.Rank) select (nint)array.GetLength(dim)).ToArray();
+            {
+                lengths = TensorSpanHelpers.FillLengths(
+                    array.Rank <= TensorShape.MaxInlineRank ? stackalloc nint[array.Rank] : new nint[array.Rank],
+                    array);
+            }
 
             nint linearLength = TensorSpanHelpers.CalculateTotalLength(lengths);
             if (array == null)
@@ -197,7 +210,11 @@ public ReadOnlyTensorSpan(Array? array, scoped ReadOnlySpan<int> start, scoped R
         public ReadOnlyTensorSpan(Array? array, scoped ReadOnlySpan<NIndex> startIndex, scoped ReadOnlySpan<nint> lengths, scoped ReadOnlySpan<nint> strides)
         {
             if (lengths.IsEmpty && array != null)
-                lengths = (from dim in Enumerable.Range(0, array.Rank) select (nint)array.GetLength(dim)).ToArray();
+            {
+                lengths = TensorSpanHelpers.FillLengths(
+                    array.Rank <= TensorShape.MaxInlineRank ? stackalloc nint[array.Rank] : new nint[array.Rank],
+                    array);
+            }
 
             nint linearLength = TensorSpanHelpers.CalculateTotalLength(lengths);
             if (array == null)
diff --git a/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/Tensor.cs b/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/Tensor.cs
@@ -6,7 +6,6 @@
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using System.Reflection.Metadata.Ecma335;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
@@ -639,29 +638,18 @@ public override int GetHashCode()
         /// <summary>
         /// Get a string representation of the tensor.
         /// </summary>
-        private string ToMetadataString()
+        private void ToMetadataString(StringBuilder sb)
         {
-            var sb = new StringBuilder("[");
+            sb.Append('[');
 
-            int n = Rank;
-            if (n == 0)
+            for (int i = 0; i < Rank; i++)
             {
-                sb.Append(']');
+                sb.Append(Lengths[i]);
+                if (i + 1 < Rank)
+                    sb.Append('x');
             }
-            else
-            {
-                for (int i = 0; i < n; i++)
-                {
-                    sb.Append(Lengths[i]);
-                    if (i + 1 < n)
-                        sb.Append('x');
-                }
-
-                sb.Append(']');
-            }
-            sb.Append($", type = {typeof(T)}, isPinned = {IsPinned}");
 
-            return sb.ToString();
+            sb.Append($"], type = {typeof(T)}, isPinned = {IsPinned}");
         }
 
         /// <summary>
@@ -671,12 +659,15 @@ private string ToMetadataString()
         /// <returns>A <see cref="string"/> representation of the <see cref="Tensor{T}"/></returns>
         public string ToString(params ReadOnlySpan<nint> maximumLengths)
         {
-            if (maximumLengths.Length == 0)
-                maximumLengths = (from number in Enumerable.Range(0, Rank) select (nint)5).ToArray();
+            if (maximumLengths.IsEmpty)
+            {
+                maximumLengths = Rank <= TensorShape.MaxInlineRank ? stackalloc nint[Rank] : new nint[Rank];
+            }
+
             var sb = new StringBuilder();
-            sb.AppendLine(ToMetadataString());
+            ToMetadataString(sb);
             sb.AppendLine("{");
-            sb.Append(AsTensorSpan().ToString(maximumLengths));
+            ((ReadOnlyTensorSpan<T>)AsTensorSpan()).ToString(sb, maximumLengths);
             sb.AppendLine("}");
             return sb.ToString();
         }
diff --git a/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorExtensions.cs b/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorExtensions.cs
@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Text;
@@ -3533,7 +3532,8 @@ public static T StdDev<T>(in ReadOnlyTensorSpan<T> x)
         /// <param name="tensor">The <see cref="TensorSpan{T}"/> you want to represent as a string.</param>
         /// <param name="maximumLengths">Maximum Length of each dimension</param>
         /// <returns>A <see cref="string"/> representation of the <paramref name="tensor"/></returns>
-        public static string ToString<T>(this in TensorSpan<T> tensor, params ReadOnlySpan<nint> maximumLengths) => ((ReadOnlyTensorSpan<T>)tensor).ToString(maximumLengths);
+        public static string ToString<T>(this in TensorSpan<T> tensor, params ReadOnlySpan<nint> maximumLengths) =>
+            ((ReadOnlyTensorSpan<T>)tensor).ToString(maximumLengths);
 
         /// <summary>
         /// Creates a <see cref="string"/> representation of the <see cref="ReadOnlyTensorSpan{T}"/>."/>
@@ -3543,11 +3543,16 @@ public static T StdDev<T>(in ReadOnlyTensorSpan<T> x)
         /// <param name="maximumLengths">Maximum Length of each dimension</param>
         public static string ToString<T>(this in ReadOnlyTensorSpan<T> tensor, params ReadOnlySpan<nint> maximumLengths)
         {
+            StringBuilder sb = new();
+            ToString(in tensor, sb, maximumLengths);
+            return sb.ToString();
+        }
 
+        internal static void ToString<T>(this in ReadOnlyTensorSpan<T> tensor, StringBuilder sb, params ReadOnlySpan<nint> maximumLengths)
+        {
             if (maximumLengths.Length != tensor.Rank)
                 ThrowHelper.ThrowArgument_DimensionsNotSame(nameof(tensor));
 
-            var sb = new StringBuilder();
             scoped Span<nint> curIndexes;
             nint[]? curIndexesArray;
             if (tensor.Rank > 6)
@@ -3579,8 +3584,6 @@ public static string ToString<T>(this in ReadOnlyTensorSpan<T> tensor, params Re
 
             if (curIndexesArray != null)
                 ArrayPool<nint>.Shared.Return(curIndexesArray);
-
-            return sb.ToString();
         }
 
         /// <summary>
@@ -3602,11 +3605,15 @@ public static Tensor<T> Transpose<T>(Tensor<T> tensor)
         {
             if (tensor.Lengths.Length < 2)
                 ThrowHelper.ThrowArgument_TransposeTooFewDimensions();
-            int[] dimension = Enumerable.Range(0, tensor.Rank).ToArray();
+
+            Span<int> dimension = tensor.Rank <= TensorShape.MaxInlineRank ? stackalloc int[tensor.Rank] : new int[tensor.Rank];
+            TensorSpanHelpers.FillRange(dimension);
+
             int temp = dimension[tensor.Rank - 1];
             dimension[tensor.Rank - 1] = dimension[tensor.Rank - 2];
             dimension[tensor.Rank - 2] = temp;
-            return PermuteDimensions(tensor, dimension.AsSpan());
+
+            return PermuteDimensions(tensor, dimension);
         }
         #endregion
 
@@ -3666,15 +3673,28 @@ public static Tensor<T> Unsqueeze<T>(this Tensor<T> tensor, int dimension)
             if (dimension < 0)
                 dimension = tensor.Rank - dimension;
 
-            List<nint> tempLengths = tensor._lengths.ToList();
-            tempLengths.Insert(dimension, 1);
-            nint[] lengths = [.. tempLengths];
-            List<nint> tempStrides = tensor.Strides.ToArray().ToList();
+            Span<nint> lengths = tensor._lengths.Length + 1 <= TensorShape.MaxInlineRank ?
+                stackalloc nint[tensor._lengths.Length + 1] :
+                new nint[tensor._lengths.Length + 1];
+            tensor._lengths.AsSpan(0, dimension).CopyTo(lengths);
+            tensor._lengths.AsSpan(dimension).CopyTo(lengths.Slice(dimension + 1));
+            lengths[dimension] = 1;
+
+            Span<nint> strides = tensor.Strides.Length + 1 <= TensorShape.MaxInlineRank ?
+                stackalloc nint[tensor.Strides.Length + 1] :
+                new nint[tensor.Strides.Length + 1];
             if (dimension == tensor.Rank)
-                tempStrides.Add(tensor.Strides[dimension - 1]);
+            {
+                tensor.Strides.CopyTo(strides);
+                strides[dimension] = tensor.Strides[dimension - 1];
+            }
             else
-                tempStrides.Insert(dimension, tensor.Strides[dimension] * tensor.Lengths[dimension]);
-            nint[] strides = [.. tempStrides];
+            {
+                tensor.Strides.Slice(0, dimension).CopyTo(strides);
+                tensor.Strides.Slice(dimension).CopyTo(strides.Slice(dimension + 1));
+                strides[dimension] = tensor.Strides[dimension] * tensor.Lengths[dimension];
+            }
+
             return new Tensor<T>(tensor._values, lengths, strides);
         }
 
@@ -3690,15 +3710,28 @@ public static TensorSpan<T> Unsqueeze<T>(in this TensorSpan<T> tensor, int dimen
             if (dimension < 0)
                 dimension = tensor.Rank - dimension;
 
-            List<nint> tempLengths = tensor.Lengths.ToArray().ToList();
-            tempLengths.Insert(dimension, 1);
-            nint[] lengths = [.. tempLengths];
-            List<nint> tempStrides = tensor.Strides.ToArray().ToList();
+            Span<nint> lengths = tensor.Lengths.Length + 1 <= TensorShape.MaxInlineRank ?
+                stackalloc nint[tensor.Lengths.Length + 1] :
+                new nint[tensor.Lengths.Length + 1];
+            tensor.Lengths.Slice(0, dimension).CopyTo(lengths);
+            tensor.Lengths.Slice(dimension).CopyTo(lengths.Slice(dimension + 1));
+            lengths[dimension] = 1;
+
+            Span<nint> strides = tensor.Strides.Length + 1 <= TensorShape.MaxInlineRank ?
+                stackalloc nint[tensor.Strides.Length + 1] :
+                new nint[tensor.Strides.Length + 1];
             if (dimension == tensor.Rank)
-                tempStrides.Add(tensor.Strides[dimension - 1]);
+            {
+                tensor.Strides.CopyTo(strides);
+                strides[dimension] = tensor.Strides[dimension - 1];
+            }
             else
-                tempStrides.Insert(dimension, tensor.Strides[dimension] * tensor.Lengths[dimension]);
-            nint[] strides = [.. tempStrides];
+            {
+                tensor.Strides.Slice(0, dimension).CopyTo(strides);
+                tensor.Strides.Slice(dimension).CopyTo(strides.Slice(dimension + 1));
+                strides[dimension] = tensor.Strides[dimension] * tensor.Lengths[dimension];
+            }
+
             return new TensorSpan<T>(ref tensor._reference, lengths, strides, tensor._shape._memoryLength);
         }
 
@@ -3714,15 +3747,28 @@ public static ReadOnlyTensorSpan<T> Unsqueeze<T>(in this ReadOnlyTensorSpan<T> t
             if (dimension < 0)
                 dimension = tensor.Rank - dimension;
 
-            List<nint> tempLengths = tensor.Lengths.ToArray().ToList();
-            tempLengths.Insert(dimension, 1);
-            nint[] lengths = [.. tempLengths];
-            List<nint> tempStrides = tensor.Strides.ToArray().ToList();
+            Span<nint> lengths = tensor.Lengths.Length + 1 <= TensorShape.MaxInlineRank ?
+                stackalloc nint[tensor.Lengths.Length + 1] :
+                new nint[tensor.Lengths.Length + 1];
+            tensor.Lengths.Slice(0, dimension).CopyTo(lengths);
+            tensor.Lengths.Slice(dimension).CopyTo(lengths.Slice(dimension + 1));
+            lengths[dimension] = 1;
+
+            Span<nint> strides = tensor.Strides.Length + 1 <= TensorShape.MaxInlineRank ?
+                stackalloc nint[tensor.Strides.Length + 1] :
+                new nint[tensor.Strides.Length + 1];
             if (dimension == tensor.Rank)
-                tempStrides.Add(tensor.Strides[dimension - 1]);
+            {
+                tensor.Strides.CopyTo(strides);
+                strides[dimension] = tensor.Strides[dimension - 1];
+            }
             else
-                tempStrides.Insert(dimension, tensor.Strides[dimension] * tensor.Lengths[dimension]);
-            nint[] strides = [.. tempStrides];
+            {
+                tensor.Strides.Slice(0, dimension).CopyTo(strides);
+                tensor.Strides.Slice(dimension).CopyTo(strides.Slice(dimension + 1));
+                strides[dimension] = tensor.Strides[dimension] * tensor.Lengths[dimension];
+            }
+
             return new ReadOnlyTensorSpan<T>(ref tensor._reference, lengths, strides, tensor._shape._memoryLength);
         }
         #endregion
diff --git a/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorHelpers.cs b/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorHelpers.cs
@@ -3,15 +3,13 @@
 
 using System;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using System.Runtime.InteropServices;
 
 namespace System.Numerics.Tensors
 {
     [Experimental(Experimentals.TensorTDiagId, UrlFormat = Experimentals.SharedUrlFormat)]
     internal static class TensorHelpers
     {
-
         /// <summary>
         /// Counts the number of true elements in a boolean filter tensor so we know how much space we will need.
         /// </summary>
diff --git a/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorSpan.cs b/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorSpan.cs
@@ -4,7 +4,6 @@
 using System.Buffers;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using EditorBrowsableAttribute = System.ComponentModel.EditorBrowsableAttribute;
@@ -144,7 +143,15 @@ public TensorSpan(Span<T> span, scoped ReadOnlySpan<nint> lengths, scoped ReadOn
         /// have a rank of 1 and a length equal to the length of the provided <see cref="Array"/>.
         /// </summary>
         /// <param name="array">The target array.</param>
-        public TensorSpan(Array? array) : this(array, ReadOnlySpan<int>.Empty, array == null ? [0] : (from dim in Enumerable.Range(0, array.Rank) select (nint)array.GetLength(dim)).ToArray(), []) { }
+        public TensorSpan(Array? array) :
+            this(array,
+                 ReadOnlySpan<int>.Empty,
+                 array == null ?
+                     [0] :
+                     TensorSpanHelpers.FillLengths(array.Rank <= TensorShape.MaxInlineRank ? stackalloc nint[array.Rank] : new nint[array.Rank], array),
+                 [])
+        {
+        }
 
         /// <summary>
         /// Creates a new <see cref="TensorSpan{T}"/> over the provided <see cref="Array"/> using the specified start offsets, lengths, and strides.
@@ -156,7 +163,11 @@ public TensorSpan(Array? array) : this(array, ReadOnlySpan<int>.Empty, array ==
         public TensorSpan(Array? array, scoped ReadOnlySpan<int> start, scoped ReadOnlySpan<nint> lengths, scoped ReadOnlySpan<nint> strides)
         {
             if (lengths.IsEmpty && array != null)
-                lengths = (from dim in Enumerable.Range(0, array.Rank) select (nint)array.GetLength(dim)).ToArray();
+            {
+                lengths = TensorSpanHelpers.FillLengths(
+                    array.Rank < TensorShape.MaxInlineRank ? stackalloc nint[array.Rank] : new nint[array.Rank],
+                    array);
+            }
 
             nint linearLength = TensorSpanHelpers.CalculateTotalLength(lengths);
 
@@ -201,7 +212,11 @@ public TensorSpan(Array? array, scoped ReadOnlySpan<int> start, scoped ReadOnlyS
         public TensorSpan(Array? array, scoped ReadOnlySpan<NIndex> startIndex, scoped ReadOnlySpan<nint> lengths, scoped ReadOnlySpan<nint> strides)
         {
             if (lengths.IsEmpty && array != null)
-                lengths = (from dim in Enumerable.Range(0, array.Rank) select (nint)array.GetLength(dim)).ToArray();
+            {
+                lengths = TensorSpanHelpers.FillLengths(
+                    array.Rank <= TensorShape.MaxInlineRank ? stackalloc nint[array.Rank] : new nint[array.Rank],
+                    array);
+            }
 
             nint linearLength = TensorSpanHelpers.CalculateTotalLength(lengths);
             strides = strides.IsEmpty ? (ReadOnlySpan<nint>)TensorSpanHelpers.CalculateStrides(lengths, linearLength) : strides;
diff --git a/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorSpanHelpers.cs b/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorSpanHelpers.cs

Original file line number	Diff line number	Diff line change
`@@ -3,15 +3,13 @@`
`3`	`3`
`4`	`4`	`using System;`
`5`	`5`	`using System.Diagnostics.CodeAnalysis;`
`6`		`-using System.Linq;`
`7`	`6`	`using System.Runtime.InteropServices;`
`8`	`7`
`9`	`8`	`namespace System.Numerics.Tensors`
`10`	`9`	`{`
`11`	`10`	`[Experimental(Experimentals.TensorTDiagId, UrlFormat = Experimentals.SharedUrlFormat)]`
`12`	`11`	`internal static class TensorHelpers`
`13`	`12`	`{`
`14`		`-`
`15`	`13`	`/// <summary>`
`16`	`14`	`/// Counts the number of true elements in a boolean filter tensor so we know how much space we will need.`
`17`	`15`	`/// </summary>`