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merged 4 commits into from
Oct 23, 2025
Merged

Fix Tensor.Reshape with wildcard #120801

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ee097f0
Fix Tensor.Reshape
lilinus Oct 16, 2025
23116eb
Add unit tests
lilinus Oct 16, 2025
9e777da
Add unit tests for TensorSpan
lilinus Oct 16, 2025
ebed3fb
Add unit tests for ReadOnlyTensorSpan
lilinus Oct 16, 2025
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2 changes: 1 addition & 1 deletion src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/Tensor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -1382,7 +1382,7 @@ public static Tensor<T> Reshape<T>(this Tensor<T> tensor, ReadOnlySpan<nint> len
else
strides = [];

return new Tensor<T>(tensor._values, tensor._start, lengths, strides);
return new Tensor<T>(tensor._values, tensor._start, newLengths, strides);
}

/// <summary>
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120 changes: 120 additions & 0 deletions src/libraries/System.Numerics.Tensors/tests/ReadOnlyTensorSpanTests.cs
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Expand Up @@ -1437,5 +1437,125 @@ public static void ToStringZeroDataTest()
""";
Assert.Equal(expected, tensor.ToString([2, 0, 2]));
}

[Fact]
public static void TensorReshapeTest()
{
int[] a = [1, 2, 3, 4, 5, 6, 7, 8, 9];
nint[] dims = [9];
var origTensor = Tensor.CreateFromShapeUninitialized<int>(dims.AsSpan(), false);
var span = a.AsTensorSpan(dims);
span.CopyTo(origTensor);
var tensor = origTensor.AsReadOnlyTensorSpan();

Assert.Equal(1, tensor.Rank);
Assert.Equal(9, tensor.Lengths[0]);
Assert.Equal(1, tensor.Strides.Length);
Assert.Equal(1, tensor.Strides[0]);
Assert.Equal(1, tensor[0]);
Assert.Equal(2, tensor[1]);
Assert.Equal(3, tensor[2]);
Assert.Equal(4, tensor[3]);
Assert.Equal(5, tensor[4]);
Assert.Equal(6, tensor[5]);
Assert.Equal(7, tensor[6]);
Assert.Equal(8, tensor[7]);
Assert.Equal(9, tensor[8]);

dims = [3, 3];
tensor = Tensor.Reshape(tensor, dims);
Assert.Equal(2, tensor.Rank);
Assert.Equal(3, tensor.Lengths[0]);
Assert.Equal(3, tensor.Lengths[1]);
Assert.Equal(2, tensor.Strides.Length);
Assert.Equal(3, tensor.Strides[0]);
Assert.Equal(1, tensor.Strides[1]);
Assert.Equal(1, tensor[0, 0]);
Assert.Equal(2, tensor[0, 1]);
Assert.Equal(3, tensor[0, 2]);
Assert.Equal(4, tensor[1, 0]);
Assert.Equal(5, tensor[1, 1]);
Assert.Equal(6, tensor[1, 2]);
Assert.Equal(7, tensor[2, 0]);
Assert.Equal(8, tensor[2, 1]);
Assert.Equal(9, tensor[2, 2]);

dims = [-1];
tensor = Tensor.Reshape(tensor, dims);
Assert.Equal(1, tensor.Rank);
Assert.Equal(9, tensor.Lengths[0]);
Assert.Equal(1, tensor.Strides.Length);
Assert.Equal(1, tensor.Strides[0]);
Assert.Equal(1, tensor[0]);
Assert.Equal(2, tensor[1]);
Assert.Equal(3, tensor[2]);
Assert.Equal(4, tensor[3]);
Assert.Equal(5, tensor[4]);
Assert.Equal(6, tensor[5]);
Assert.Equal(7, tensor[6]);
Assert.Equal(8, tensor[7]);
Assert.Equal(9, tensor[8]);

dims = [3, -1];
tensor = Tensor.Reshape(tensor, dims);
Assert.Equal(2, tensor.Rank);
Assert.Equal(3, tensor.Lengths[0]);
Assert.Equal(3, tensor.Lengths[1]);
Assert.Equal(2, tensor.Strides.Length);
Assert.Equal(3, tensor.Strides[0]);
Assert.Equal(1, tensor.Strides[1]);
Assert.Equal(1, tensor[0, 0]);
Assert.Equal(2, tensor[0, 1]);
Assert.Equal(3, tensor[0, 2]);
Assert.Equal(4, tensor[1, 0]);
Assert.Equal(5, tensor[1, 1]);
Assert.Equal(6, tensor[1, 2]);
Assert.Equal(7, tensor[2, 0]);
Assert.Equal(8, tensor[2, 1]);
Assert.Equal(9, tensor[2, 2]);

Assert.Throws<ArgumentException>(() => Tensor.Reshape(origTensor.AsReadOnlyTensorSpan(), [-1, -1]));

Assert.Throws<ArgumentException>(() => Tensor.Reshape(origTensor.AsReadOnlyTensorSpan(), [1, 2, 3, 4, 5]));

// Make sure reshape works correctly with 0 strides.
origTensor = Tensor.CreateFromShape<int>((ReadOnlySpan<nint>)[2], [0], false);
tensor = origTensor.AsReadOnlyTensorSpan();
tensor = Tensor.Reshape(tensor, [1, 2]);
Assert.Equal(2, tensor.Rank);
Assert.Equal(1, tensor.Lengths[0]);
Assert.Equal(2, tensor.Lengths[1]);
Assert.Equal(0, tensor.Strides[0]);
Assert.Equal(0, tensor.Strides[1]);

origTensor = Tensor.CreateFromShape<int>((ReadOnlySpan<nint>)[2], [0], false);
tensor = origTensor.AsReadOnlyTensorSpan();
tensor = Tensor.Reshape(tensor, [2, 1]);
Assert.Equal(2, tensor.Rank);
Assert.Equal(2, tensor.Lengths[0]);
Assert.Equal(1, tensor.Lengths[1]);
Assert.Equal(0, tensor.Strides[0]);
Assert.Equal(0, tensor.Strides[1]);

tensor = Tensor.Reshape(tensor, [1, 2, 1]);
Assert.Equal(3, tensor.Rank);
Assert.Equal(1, tensor.Lengths[0]);
Assert.Equal(2, tensor.Lengths[1]);
Assert.Equal(1, tensor.Lengths[2]);
Assert.Equal(0, tensor.Strides[0]);
Assert.Equal(0, tensor.Strides[1]);
Assert.Equal(0, tensor.Strides[2]);

tensor = Tensor.Reshape(tensor, [1, 1, -1, 1]);
Assert.Equal(4, tensor.Rank);
Assert.Equal(1, tensor.Lengths[0]);
Assert.Equal(1, tensor.Lengths[1]);
Assert.Equal(2, tensor.Lengths[2]);
Assert.Equal(1, tensor.Lengths[3]);
Assert.Equal(0, tensor.Strides[0]);
Assert.Equal(0, tensor.Strides[1]);
Assert.Equal(0, tensor.Strides[2]);
Assert.Equal(0, tensor.Strides[3]);
}
}
}
120 changes: 120 additions & 0 deletions src/libraries/System.Numerics.Tensors/tests/TensorSpanTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2077,5 +2077,125 @@ public static void ToStringZeroDataTest()
""";
Assert.Equal(expected, tensor.ToString([2, 0, 2]));
}

[Fact]
public static void TensorReshapeTest()
{
int[] a = [1, 2, 3, 4, 5, 6, 7, 8, 9];
nint[] dims = [9];
var origTensor = Tensor.CreateFromShapeUninitialized<int>(dims.AsSpan(), false);
var span = a.AsTensorSpan(dims);
span.CopyTo(origTensor);
var tensor = origTensor.AsTensorSpan();

Assert.Equal(1, tensor.Rank);
Assert.Equal(9, tensor.Lengths[0]);
Assert.Equal(1, tensor.Strides.Length);
Assert.Equal(1, tensor.Strides[0]);
Assert.Equal(1, tensor[0]);
Assert.Equal(2, tensor[1]);
Assert.Equal(3, tensor[2]);
Assert.Equal(4, tensor[3]);
Assert.Equal(5, tensor[4]);
Assert.Equal(6, tensor[5]);
Assert.Equal(7, tensor[6]);
Assert.Equal(8, tensor[7]);
Assert.Equal(9, tensor[8]);

dims = [3, 3];
tensor = Tensor.Reshape(tensor, dims);
Assert.Equal(2, tensor.Rank);
Assert.Equal(3, tensor.Lengths[0]);
Assert.Equal(3, tensor.Lengths[1]);
Assert.Equal(2, tensor.Strides.Length);
Assert.Equal(3, tensor.Strides[0]);
Assert.Equal(1, tensor.Strides[1]);
Assert.Equal(1, tensor[0, 0]);
Assert.Equal(2, tensor[0, 1]);
Assert.Equal(3, tensor[0, 2]);
Assert.Equal(4, tensor[1, 0]);
Assert.Equal(5, tensor[1, 1]);
Assert.Equal(6, tensor[1, 2]);
Assert.Equal(7, tensor[2, 0]);
Assert.Equal(8, tensor[2, 1]);
Assert.Equal(9, tensor[2, 2]);

dims = [-1];
tensor = Tensor.Reshape(tensor, dims);
Assert.Equal(1, tensor.Rank);
Assert.Equal(9, tensor.Lengths[0]);
Assert.Equal(1, tensor.Strides.Length);
Assert.Equal(1, tensor.Strides[0]);
Assert.Equal(1, tensor[0]);
Assert.Equal(2, tensor[1]);
Assert.Equal(3, tensor[2]);
Assert.Equal(4, tensor[3]);
Assert.Equal(5, tensor[4]);
Assert.Equal(6, tensor[5]);
Assert.Equal(7, tensor[6]);
Assert.Equal(8, tensor[7]);
Assert.Equal(9, tensor[8]);

dims = [3, -1];
tensor = Tensor.Reshape(tensor, dims);
Assert.Equal(2, tensor.Rank);
Assert.Equal(3, tensor.Lengths[0]);
Assert.Equal(3, tensor.Lengths[1]);
Assert.Equal(2, tensor.Strides.Length);
Assert.Equal(3, tensor.Strides[0]);
Assert.Equal(1, tensor.Strides[1]);
Assert.Equal(1, tensor[0, 0]);
Assert.Equal(2, tensor[0, 1]);
Assert.Equal(3, tensor[0, 2]);
Assert.Equal(4, tensor[1, 0]);
Assert.Equal(5, tensor[1, 1]);
Assert.Equal(6, tensor[1, 2]);
Assert.Equal(7, tensor[2, 0]);
Assert.Equal(8, tensor[2, 1]);
Assert.Equal(9, tensor[2, 2]);

Assert.Throws<ArgumentException>(() => Tensor.Reshape(origTensor.AsTensorSpan(), [-1, -1]));

Assert.Throws<ArgumentException>(() => Tensor.Reshape(origTensor.AsTensorSpan(), [1, 2, 3, 4, 5]));

// Make sure reshape works correctly with 0 strides.
origTensor = Tensor.CreateFromShape<int>((ReadOnlySpan<nint>)[2], [0], false);
tensor = origTensor.AsTensorSpan();
tensor = Tensor.Reshape(tensor, [1, 2]);
Assert.Equal(2, tensor.Rank);
Assert.Equal(1, tensor.Lengths[0]);
Assert.Equal(2, tensor.Lengths[1]);
Assert.Equal(0, tensor.Strides[0]);
Assert.Equal(0, tensor.Strides[1]);

origTensor = Tensor.CreateFromShape<int>((ReadOnlySpan<nint>)[2], [0], false);
tensor = origTensor.AsTensorSpan();
tensor = Tensor.Reshape(tensor, [2, 1]);
Assert.Equal(2, tensor.Rank);
Assert.Equal(2, tensor.Lengths[0]);
Assert.Equal(1, tensor.Lengths[1]);
Assert.Equal(0, tensor.Strides[0]);
Assert.Equal(0, tensor.Strides[1]);

tensor = Tensor.Reshape(tensor, [1, 2, 1]);
Assert.Equal(3, tensor.Rank);
Assert.Equal(1, tensor.Lengths[0]);
Assert.Equal(2, tensor.Lengths[1]);
Assert.Equal(1, tensor.Lengths[2]);
Assert.Equal(0, tensor.Strides[0]);
Assert.Equal(0, tensor.Strides[1]);
Assert.Equal(0, tensor.Strides[2]);

tensor = Tensor.Reshape(tensor, [1, 1, -1, 1]);
Assert.Equal(4, tensor.Rank);
Assert.Equal(1, tensor.Lengths[0]);
Assert.Equal(1, tensor.Lengths[1]);
Assert.Equal(2, tensor.Lengths[2]);
Assert.Equal(1, tensor.Lengths[3]);
Assert.Equal(0, tensor.Strides[0]);
Assert.Equal(0, tensor.Strides[1]);
Assert.Equal(0, tensor.Strides[2]);
Assert.Equal(0, tensor.Strides[3]);
}
}
}
47 changes: 47 additions & 0 deletions src/libraries/System.Numerics.Tensors/tests/TensorTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2219,6 +2219,42 @@ public static void TensorReshapeTest()
Assert.Equal(8, tensor[2, 1]);
Assert.Equal(9, tensor[2, 2]);

dims = [-1];
tensor = Tensor.Reshape(tensor, dims);
Assert.Equal(1, tensor.Rank);
Assert.Equal(9, tensor.Lengths[0]);
Assert.Equal(1, tensor.Strides.Length);
Assert.Equal(1, tensor.Strides[0]);
Assert.Equal(1, tensor[0]);
Assert.Equal(2, tensor[1]);
Assert.Equal(3, tensor[2]);
Assert.Equal(4, tensor[3]);
Assert.Equal(5, tensor[4]);
Assert.Equal(6, tensor[5]);
Assert.Equal(7, tensor[6]);
Assert.Equal(8, tensor[7]);
Assert.Equal(9, tensor[8]);

dims = [3, -1];
tensor = Tensor.Reshape(tensor, dims);
Assert.Equal(2, tensor.Rank);
Assert.Equal(3, tensor.Lengths[0]);
Assert.Equal(3, tensor.Lengths[1]);
Assert.Equal(2, tensor.Strides.Length);
Assert.Equal(3, tensor.Strides[0]);
Assert.Equal(1, tensor.Strides[1]);
Assert.Equal(1, tensor[0, 0]);
Assert.Equal(2, tensor[0, 1]);
Assert.Equal(3, tensor[0, 2]);
Assert.Equal(4, tensor[1, 0]);
Assert.Equal(5, tensor[1, 1]);
Assert.Equal(6, tensor[1, 2]);
Assert.Equal(7, tensor[2, 0]);
Assert.Equal(8, tensor[2, 1]);
Assert.Equal(9, tensor[2, 2]);

Assert.Throws<ArgumentException>(() => Tensor.Reshape(tensor, [-1, -1]));

Assert.Throws<ArgumentException>(() => Tensor.Reshape(tensor, [1, 2, 3, 4, 5]));

// Make sure reshape works correctly with 0 strides.
Expand Down Expand Up @@ -2246,6 +2282,17 @@ public static void TensorReshapeTest()
Assert.Equal(0, tensor.Strides[0]);
Assert.Equal(0, tensor.Strides[1]);
Assert.Equal(0, tensor.Strides[2]);

tensor = Tensor.Reshape(tensor, [1, 1, -1, 1]);
Assert.Equal(4, tensor.Rank);
Assert.Equal(1, tensor.Lengths[0]);
Assert.Equal(1, tensor.Lengths[1]);
Assert.Equal(2, tensor.Lengths[2]);
Assert.Equal(1, tensor.Lengths[3]);
Assert.Equal(0, tensor.Strides[0]);
Assert.Equal(0, tensor.Strides[1]);
Assert.Equal(0, tensor.Strides[2]);
Assert.Equal(0, tensor.Strides[3]);
}

[Fact]
Expand Down
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