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Nan Zhang

PROFILE

Nan Zhang

Nanzha worked on backend and compiler internals for the pytorch/pytorch and graphcore/pytorch-fork repositories, focusing on dynamic shape handling, kernel autotuning, and robustness in Inductor lowering. Using Python, PyTorch, and Triton, Nanzha delivered features such as dilation-aware pooling, SymInt placeholder support for dynamic reshaping, and autotuning enhancements for ROCm kernels. The work included targeted bug fixes for edge cases in power-of-two calculations, stride padding, and kernel grid compatibility, as well as improvements to lowering logic for primitives like scalar_tensor and arange. Comprehensive testing and code generation optimizations ensured stable, performant, and maintainable backend workflows across evolving codebases.

Overall Statistics

Feature vs Bugs

45%Features

Repository Contributions

15Total
Bugs
6
Commits
15
Features
5
Lines of code
388
Activity Months6

Work History

April 2026

3 Commits

Apr 1, 2026

Concise monthly summary for 2026-04 focusing on Inductor-related robustness and lowering improvements in the pytorch/pytorch repository. The month highlights feature deliveries, major bug fixes, and the resulting business value and technical impact.

March 2026

3 Commits • 1 Features

Mar 1, 2026

March 2026: Implemented dilation-aware kernel sizing for max_pool2d_with_indices_backward in Inductor lowering, added tests, and integrated the op into SAFE_AND_PERFORMANT_INDUCTOR_OPS to ensure backends don’t fallback to unsupported kernels. Fixed CantSplit error in _split_iteration_ranges with unit tests, improving reduction tiling reliability and correctness. Resulting changes improve backend compatibility, stability, and performance portability for dilation-enabled pooling paths.

February 2026

1 Commits

Feb 1, 2026

February 2026 (2026-02) monthly summary for the pytorch/pytorch repository focused on delivering a robust bug fix for next_power_of_2, with clear impact on correctness and downstream stability.

November 2025

2 Commits • 1 Features

Nov 1, 2025

November 2025: Delivered SymInt placeholder support in the FXIR wrapper for pytorch/pytorch, enabling dynamic reshaping with symbolic integers and adding tests for dynamic info from placeholders and TMD. The changes were merged via PR 167757 (Differential Revision: D86984100), reinforcing dynamic shape capabilities in the FX IR path and expanding test coverage.

October 2025

3 Commits • 3 Features

Oct 1, 2025

October 2025 performance summary focusing on delivering high-impact features and robustness across ROCm/pytorch and PyTorch codegen stacks. The quarter’s work emphasized performance optimization, codegen efficiency, and broader backend compatibility to enable stronger business outcomes and scalability.

September 2025

3 Commits

Sep 1, 2025

September 2025 focused on stabilizing dynamic shape and autotuning workflows in graphcore/pytorch-fork. Delivered three targeted bug fixes that restore correctness and test reliability: (1) user-defined Triton kernel grid calculation test fix to ensure functionality after upstream changes; (2) revert dynamic strides padding behavior in dynamic shapes to align with whether shape or stride is dynamic; (3) revert FloorDiv implementation from C to Python for MTIA grid compatibility. These changes reduce regression risk in autotuning, improve runtime predictability for dynamic workloads, and improve maintainability by consolidating critical grid calculations in Python where appropriate. All work was implemented with targeted tests and clear PR traceability, enabling safer future migrations and easier rollback if needed.

Activity

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Quality Metrics

Correctness94.0%
Maintainability85.4%
Architecture85.4%
Performance84.6%
AI Usage24.0%

Skills & Technologies

Programming Languages

Python

Technical Skills

Backend DevelopmentCode GenerationCompiler InternalsDynamic ReshapingDynamic Shape HandlingMathematicsOptimizationPyTorchPythonPython DevelopmentSymPyTensor OperationsTestingTritonUnit Testing

Repositories Contributed To

3 repos

Overview of all repositories you've contributed to across your timeline

pytorch/pytorch

Oct 2025 Apr 2026
5 Months active

Languages Used

Python

Technical Skills

Backend DevelopmentCode GenerationCompiler InternalsOptimizationPyTorchTesting

graphcore/pytorch-fork

Sep 2025 Sep 2025
1 Month active

Languages Used

Python

Technical Skills

MathematicsPythonSymPyalgorithm optimizationbackend development

ROCm/pytorch

Oct 2025 Oct 2025
1 Month active

Languages Used

Python

Technical Skills

Pythonmachine learningperformance optimization