Extracting local and global numbering of meshes for PETSc

Question

How can I extract vectors with local and global nodes numbering for structured and unstructured meshes from the openCARP code written so far? I am planning to write a code which works with PETSc routines for index sets (IS) and MatIS, but in order to use them I need how to extract infomation useful to build index sets.

Thank you in advance

Answer 1

Not sure if I understood your question correctly but if you are looking for index mappings, see

• SF::local_nodal_to_local_petsc
• SF::local_petsc_to_local_nodal
• SF::local_petsc_to_nodal_mapping

and

https://git.opencarp.org/openCARP/openCARP/-/blob/master/physics/electrics.cc#L208

Comments

Thank you very much, I'll have a look. My question basically was related to the possibility of adding PETSc MatIS to openCARP source code, since having index set matrices can be useful in order to implement further numerical schemes

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Work is done currently to remove essential PETSc dependencies (abstract vector rather than PETSc vectors etc.): https://git.opencarp.org/openCARP/openCARP/-/merge_requests/79

The default numerical backend will still be PETSc but we would like to remove the PETSc dependency if another backend (for example Ginkgo) is used. Thus, we would likely not introduce new PETSc dependencies in the core openCARP code.