Improved Trapezoidal Mapping for FGM - Update

[tkiymaz]

Proposed Changes

The original trapezoidal map implementation needs excessive memory for large lookup tables (LUT) (e.g., 300+ MB for tables with ~80k points). This PR introduces a new memory-efficient trapezoidal map implementation (LUT_FAST) for Flamelet-Generated Manifold (FGM) lookup tables, based on LUT algorithm of Pedro Gomes. The new implementation reduces memory usage while maintaining query performance. A new unit test is created and all tests are passed.

Related Work

This code is an implementation of https://github.com/pcarruscag/LUT to SU2.

PR Checklist

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• [ x] I am submitting my contribution to the develop branch.
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• [x ] I have added a test case that demonstrates my contribution, if necessary.
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[bigfooted]

just remove the old trapezoidal map and use the new one for everything. Just rename trapezoidalmapFAST trapezoidalmap.

[tkiymaz]

I have verified the new implementation against the old one using the fgm unsteady testcase. It produces identical history and restart files. Map memory for the 7k-point FGM table drops from 18.2 MB to 1.3 MB.

[bigfooted]

@tkiymaz can you fix the conflicts so the regression tests run again?

[bigfooted]

Ok great, If you think it's ready just remove the WIP and pr:draft label

[tkiymaz]

Ok great, If you think it's ready just remove the WIP and pr:draft label

I tested couple of times, I think it is ready. I changed the title and remove the pr:draft label.

[bigfooted]

@tkiymaz can you fix this sometime soon so it can be merged in before the next release?

[bigfooted]

@tkiymaz @pcarruscag there are 2 testcases with slightly different residuals, even though they do not use any of the code that was touched as far as I can tell. Both cases are AD-related. The residual mismatch might not be related to this PR.