Hi I there a place to read about how I can manipulate the left hand matrix (and right hand vector) in a way that is consistent with with parallel execution? And effective. For now I just need to couple 2 linear systems (poisson equation), but I would like to understand the process so that I can do…

By manipulate do you mean do a custom assembly? This test shows how to do a custom assembly in python. You want to couple 2 Poisson problems on the same mesh or different meshes?

Thanks, I’ll take a closer look at it later, I think it will be informative when I dig into it, but after a brief look it reminds me of one of the things that confuses me. Those scatter forward and backwards what do they do, when do I call them? My internet searches so far has not been very fruitfu…

[image] torhans: Regarding the 2 poissons; what I hope to do is to split a mesh along an internal subdomain boundary and make a discontinuity in the potential. There are plenty of ways to do that without fiddling with the low level matrices, for instance: https://multiphenics.github.io/ Dis…

[image] torhans: Those scatter forward and backwards what do they do, when do I call them? My internet searches so far has not been very fruitful, so a pointer to some explanation would be helpful. They are covered in https://scientificcomputing.github.io/mpi-tutorial/notebooks/dolfinx_MPI_t…

Manipulating matrix directly

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francesco-ballarin November 8, 2024, 6:32am 4

There are plenty of ways to do that without fiddling with the low level matrices, for instance:

https://multiphenics.github.io/
Discontinuity at interface using mixed domains

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Manipulating matrix directly

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