Remi Lehe

Thanks for reporting this issue. ~~In the above case, could you let us know how you setup the environment and installed dependencies for WarpX?~~ ~~Did you follow one of the...

Thanks for the PR @archermarx

Thanks for reporting this issue. Could you post the input script that you use when injecting particles from an external file? Also: how many macroparticles does the external file contain?...

Sorry: I was supposed to review this PR, but got side-tracked by other deadlines. I can try to review it today.

@ax3l Should this be merged or closed?

Hi, Thanks for your question. For this use case, I would recommend using an electrostatic solver instead of a Maxwell solver. Here is an example using a relativistic electrostatic solver:...

@cr-xu Thanks for opening the issue. It seems that switching from `.sample` to `.rsample` fixes this: ```python import torch from torch.distributions.multivariate_normal import MultivariateNormal mean = torch.tensor([0.0], requires_grad=True) cov = torch.tensor([[1.0]])...

@cr-xu Do you see any issue with switching from `.sample` to `.rsample` throughout Cheetah?

@lucafedeli88 pointed out that this process is implemented in: - CALDER (see https://indico.ijclab.in2p3.fr/event/8018/contributions/25315/attachments/18864/25444/Workshop_GDR_APPEL22_Gremillet_v3.pdf and https://theses.hal.science/tel-03653070) - Osiris (see https://ui.adsabs.harvard.edu/abs/2017APS..DPPB11030D/abstract, [https://www.cambridge.org/core/journals/journal-of-plasma-physics/article/compton-sca[…]ing-in-particleincell-codes/4A2BE5F3AB821F6B7D45E36CC0FBB48F](https://www.cambridge.org/core/journals/journal-of-plasma-physics/article/compton-scattering-in-particleincell-codes/4A2BE5F3AB821F6B7D45E36CC0FBB48F, https://arxiv.org/abs/2003.04249)

Another useful reference: https://journals.aps.org/prab/pdf/10.1103/PhysRevAccelBeams.25.084601