Pty-Chi: A PyTorch-based modern ptychographic data analysis package

TL;DR

Pty-Chi is an open-source, PyTorch-based software package that advances ptychographic data reconstruction by integrating modern algorithms, automatic differentiation, and GPU acceleration for versatile, high-resolution imaging.

Contribution

It introduces a flexible, extendable ptychographic reconstruction framework built on PyTorch, supporting advanced modeling and machine learning integration.

Findings

Demonstrates accurate reconstructions with limited coherence and low overlap.

Showcases GPU-accelerated, multi-device processing capabilities.

Highlights extensibility for new algorithms and experimental models.

Abstract

Ptychography has become an indispensable tool for high-resolution, non-destructive imaging using coherent light sources. The processing of ptychographic data critically depends on robust, efficient, and flexible computational reconstruction software. We introduce Pty-Chi, an open-source ptychographic reconstruction package built on PyTorch that unifies state-of-the-art analytical algorithms with automatic differentiation methods. Pty-Chi provides a comprehensive suite of reconstruction algorithms while supporting advanced experimental parameter corrections such as orthogonal probe relaxation and multislice modeling. Leveraging PyTorch as the computational backend ensures vendor-agnostic GPU acceleration, multi-device parallelization, and seamless access to modern optimizers. An object-oriented, modular design makes Pty-Chi highly extendable, enabling researchers to prototype new imaging models, integrate machine learning approaches, or build entirely new workflows on top of its core components. We demonstrate Pty-Chi's capabilities through challenging case studies that involve limited coherence, low overlap, and unstable illumination during scanning, which highlight its accuracy, versatility, and extensibility. With community-driven development and open contribution, Pty-Chi offers a modern, maintainable platform for advancing computational ptychography and for enabling innovative imaging algorithms at synchrotron facilities and beyond.