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Pull request overview
This PR adds comprehensive support for the bfloat16 type to TorchSharp, fixing issue #1469 where bfloat16 tensors could not be printed. The implementation includes a new BFloat16 struct, tensor factory methods, conversion utilities, and extensive test coverage. Additionally, the PR fixes missing ToString support for Float16 types.
Changes:
- Introduced a new
BFloat16struct with IEEE 754-compliant conversion logic using round-to-nearest-even - Added tensor factory methods, Scalar conversions, and extension methods for BFloat16
- Fixed missing ToCSharpString and PrintValue handling for both BFloat16 and Float16 types
- Comprehensive test coverage including ToString, data accessors, round-trip conversions, and multidimensional tensor creation
Reviewed changes
Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.
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| File | Description |
|---|---|
| src/TorchSharp/BFloat16.cs | New BFloat16 struct with conversion operators, arithmetic operators, and comparison operators |
| src/TorchSharp/Scalar.cs | Added BFloat16 implicit conversion and extension methods for ToScalar/ToBFloat16 |
| src/TorchSharp/Tensor/Tensor.cs | Updated ValidateType, ToCSharpString, PrintValue to handle BFloat16; added BFloat16 to type mapping; fixed Float16 ToString support |
| src/TorchSharp/Tensor/TensorExtensionMethods.cs | Added BFloat16 support to ToTensor generic methods and new ToBFloat16 extension |
| src/TorchSharp/Tensor/Factories/tensor_BFloat16.cs | Complete set of tensor factory methods for BFloat16 arrays and multidimensional arrays |
| src/TorchSharp/Tensor/Factories/as_tensor.cs | Added as_tensor overloads for BFloat16 arrays and IList |
| src/TorchSharp/Tensor/Factories/Tensor.Factories.cs | Added BFloat16 and Float16 to offset calculation in frombuffer |
| test/TorchSharpTest/TestTorchTensor.cs | Comprehensive tests for BFloat16 ToString, data access, round-trip conversion, tensor creation, struct operations, and Float16 ToString |
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Added BFloat16 case to PrintValue() and ToCSharpString() so that bfloat16 (and float16) tensors can be printed in all string styles.
Add test coverage for the bfloat16/float16 printing fix: - TestBFloat16ScalarToString: scalar tensor in jlstr, npstr, cstr formats - TestBFloat16TensorToString: 1-D and 2-D tensors in numpy, julia, csharp formats plus print() - TestFloat16TensorToString: 1-D tensors in csharp and numpy formats Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Implement a custom BFloat16 struct (2 bytes, binary-compatible with c10::BFloat16) with round-to-nearest-even conversion matching PyTorch. New features: - BFloat16 struct with arithmetic, comparison, and conversion operators - data<BFloat16>() and item<BFloat16>() for zero-copy tensor data access - torch.tensor(BFloat16[], ...) factory overloads for 1D-4D arrays - Scalar implicit conversion and ToBFloat16() extraction - ToBFloat16() tensor extension method - ToTensor<T> support for BFloat16 - as_tensor() BFloat16 overloads - frombuffer offset fix for BFloat16 and Float16 (2-byte types) Fixes dotnet#1469 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Pull request overview
Copilot reviewed 8 out of 8 changed files in this pull request and generated 4 comments.
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- Fix ArgumentException parameter order in ToTensor<T> - Add scalar tensor(BFloat16) overload for 0-D tensor consistency - Align Equals/GetHashCode with ==/!= operators using ToSingle() - Redefine Epsilon as smallest positive value (.NET convention), add MinNormal Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
cincuranet
reviewed
Apr 8, 2026
| /// Binary-compatible with c10::BFloat16 in LibTorch. | ||
| /// </summary> | ||
| [StructLayout(LayoutKind.Sequential)] | ||
| public readonly struct BFloat16 : IComparable<BFloat16>, IEquatable<BFloat16>, IComparable, IFormattable |
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Is this BFloat16 different from System.Numerics.BFloat16 that's now available in .NET 11?
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I have to check, but the problem is we are now building with .net 8 only and I don't think directly jumping to 11 would be okay
cincuranet
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Apr 8, 2026
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Fixes #1469