Streaming: Histogramming of Particle Data

@aeriforme would like to write a data pipeline that takes all particle data and bins it to a 1D or 2D user-defined histogram. This would be a great application of our work in @franzpoeschel et al. https://arxiv.org/abs/2107.06108.

Idea: Let's take the script in https://github.com/openPMD/openPMD-api/blob/dev/src/cli/pipe.py as a template and instead of forwarding the data 1:1 to another file format, we call np.histogram (1D) or np.histogram2d (2D) to store into a histogram per process. Finally, we reduce the histograms (sum) via mpi4py and write them out into a 2D mesh (or simple np.save from rank 0).

@aeriforme works with CINECA clusters.

Ref.:

• https://github.com/ECP-WarpX/WarpX/issues/3033