Second Coupling Integral (times d tilde/dn)

[int-ptr-ptr]

Description

Please describe the changes/features in this pull request.

• Creates a new (temporary) function for computing the coupling integral in additional integral in integrate-coupling #1550
• Writes a test to verify this new function

Issue Number

If there is an issue created for these changes, link it here
solves #1550

Checklist

Please make sure to check developer documentation on specfem docs.

• I ran the code through pre-commit to check style
• THE DOCUMENTATION BUILDS WITHOUT WARNINGS/ERRORS
• I have added labels to the PR (see right hand side of the PR page)
• My code passes all the integration tests
• I have added sufficient unittests to test my changes
• I have added/updated documentation for the changes I am proposing
• I have updated CMakeLists to ensure my code builds
• My code builds across all platforms

[Rohit-Kakodkar]

It looks like you're making updates unrelated to the coupling integral in this PR, unless I've missed something. Would you mind updating this PR to include just the coupling integral and its test? I'm unsure where the nonconforming fixture is used—please correct me if I'm wrong. Thanks!

[Rohit-Kakodkar]

Precomputing edge-related values and storing them in the assembly can clean up this code, improve readability, and facilitate integration into coupling_integral.

[int-ptr-ptr]

Is it alright if we do this in a future PR? I was waiting for this one to go through before updating my work on #1342 in order to put the first coupling_integral in the same test executable.

Precomputation and storage would require changes to nonconforming_interfaces that will bloat this PR even further.

[Rohit-Kakodkar]

That sounds good. Can you create another issue for that refactor and link it here?

Also, see my other comment.

[lsawade]

I'm not quite understanding why you are rewriting GLL routines here.

See: core/specfem/quadrature/gll/lagrange_poly.cpp

[int-ptr-ptr]

I'm not quite understanding why you are rewriting GLL routines here.

See: core/specfem/quadrature/gll/lagrange_poly.cpp

I had not seen that, as I overlooked the gll namespace (since I wanted other schemes). I noticed that lagrange_poly.xpp uses views. I like how fixture has compile-time (constexpr) access to the quadrature, though I do not explicitly need it at the moment, as well as how it avoids the Kokkos::View dependence.

[lsawade]

@int-ptr-ptr, how are your notes coming along?