PPL opacity models

[chongchonghe]

Description

Main updates:

• Defined three opacity models described in Paper III: piecewise constant (piecewise_constant_opacity), piecewise powerlaw with fixed slope (PPL_opacity_fixed_slope_spectrum), piecewise powerlaw with full spectrum fitting (PPL_opacity_full_spectrum).

• Added tests for each of these methods.

  • RadhydroBB tests the PC method's ability to resolve the Doppler-shifted spectrum in a moving blackbody.
  • RadMarshakVaytet tests the ability of all three methods (by default PPL_opacity_full_spectrum) to deal with frequency-dependent velocities within an energy bin.
  • RadTube tests that in the special case of opacity being independent of frequency, the PPL_opacity_fixed_slope_spectrum method provides the same result as the single-group method.
  • RadhydroShockMultigroup tests PPL_opacity_full_spectrum in the special case of constant opacity.

More updates:

• Removed ComputePlanckOpacityTempDerivative
• Defined ComputeDiffusionFluxMeanOpacity and removed the calculation of component-specific flux-mean opacity. See Paper III.
• Defined ComputeBinCenterOpacity to use when opacity_model_ == OpacityModel::PPL_opacity_full_spectrum and use_diffuse_flux_mean_opacity = false.
• Changed the structure of the Newton-Raphson iteration loop. We check the residuals first, then calculate opacities and the Jacobian.
• Fixed a bug in the Newton iteration where the calculation of alpha_E uses Erad0Vec but EradVec_guess should be used.
• More robust break condition for the Newton iteration.
• Stop updating alpha_E and alpha_B after max_ite_to_update_alpha_E steps in the Newton iteration.
• Set reconstructionOrder_=3 in the RadTube and RadhydroShockMultigroup tests to avoid "erroneous arithmetic" error after using -DCMAKE_CXX_FLAGS=-ffp-exception-behavior=strict.

Checklist

Before this pull request can be reviewed, all of these tasks should be completed. Denote completed tasks with an x inside the square brackets [ ] in the Markdown source below:

• I have added a description (see above).
• I have added a link to any related issues see (see above).
• I have read the [Contributing Guide](https://github.com/quokka-astro/quokka/blob/development/CONTRIBUTING.md).
• I have added tests for any new physics that this PR adds to the code.
• I have tested this PR on my local computer and all tests pass.
• I have manually triggered the GPU tests with the magic comment /azp run.
• I have requested a reviewer for this PR.

[chongchonghe]

It looks like the CUDA version does not successfully compile: https://dev.azure.com/quokka-code/quokka-CI/_build/results?buildId=10712&view=logs&j=655dacad-9e02-5f72-e0cf-043ebfb7cecc&t=e95f4446-ac23-5f52-1703-4ff6a9656172

Yes, I know. I'm working on it.

[chongchonghe]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[chongchonghe]

🍻 All tests passed!
@markkrumholz @BenWibking Can you review this PR?

[chongchonghe]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).