PyNX.Ptycho: a computing library for X-ray coherent diffraction imaging of nanostructures

X-ray imaging techniques have undergone a remarkable development during the past decade, taking advantage of coherent X-ray sources. Among these techniques, ptychography allows reconstruction of the specimen and the illumination probe from a series of diffraction patterns without any prior knowledge about the sample. However, the reconstruction of the ptychographic data remains challenging and the reconstruction software is often not publicly available. Presented here is an open-source library for the reconstruction of two-dimensional ptychographic data, written in Python. This library implements existing algorithms, with examples of data reconstruction on both simulated and experimental (Bragg ptychography on heterogeneous strained InAs/GaAs nanowires) data sets. It can be used for educational (simulation) purposes or experimental data analysis, and also features an OpenCL version of the ptychography algorithm for high-performance computing.