Simplify Molar Mixture Properties

[ischoegl]

Changes proposed in this pull request

There are some instances where ThermoPhase objects use redundant code for the evaluation of molar mixture properties.

This PR seeks to provide a more uniform approach to evaluating molar properties. By default, average properties should be calculated as a weighted sum, e.g. $\bar{h} = \sum X_k \bar{h}_k$. getPartialMolar<> getters are used to obtain partial molar properties.

• default behavior for molar mixture properties is changed to summation rather than throwing an exception
• improve exception handling for any virtual ThermoPhase method that is not implemented
• redundant/equivalent overrides are removed unless speed advantages are apparent

One caveat is that this approach has limitations for intEnergy_mole and cv_mole. These properties are implemented differently as they are largely based on simplified thermodynamic relationships rather than summations. Interestingly, an attempt to base intEnergy_mole on getPartialMolarIntEnergies causes failures in the zeroD module, albeit only on windows and sundials runners.

Checklist

• The pull request includes a clear description of this code change
• Commit messages have short titles and reference relevant issues
• Build passes (scons build & scons test) and unit tests address code coverage
• Style & formatting of contributed code follows contributing guidelines
• The pull request is ready for review

[codecov]

Codecov Report

Attention: Patch coverage is 78.16092% with 19 lines in your changes missing coverage. Please review.

Project coverage is 74.39%. Comparing base (2e0d8ac) to head (809181e).
Report is 11 commits behind head on main.

Files with missing lines	Patch %	Lines
include/cantera/thermo/ThermoPhase.h	61.36%	17 Missing ⚠️
include/cantera/base/Solution.h	60.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1837      +/-   ##
==========================================
- Coverage   74.41%   74.39%   -0.03%     
==========================================
  Files         382      382              
  Lines       53411    53330      -81     
  Branches     9026     9021       -5     
==========================================
- Hits        39747    39676      -71     
+ Misses      10617    10607      -10     
  Partials     3047     3047              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[speth]

Thanks for this, @ischoegl. My comments here are mostly about the documentation related to these changes.

I'm curious about the test failures when replacing intEnergy_mole and cv_mole that you mentioned cropping up on specific runners.

[ischoegl]

Thanks for the review, @speth. I've taken care of all requests.

I'm curious about the test failures when replacing intEnergy_mole and cv_mole that you mentioned cropping up on specific runners.

While I have deleted those commits, I recall having to change some of the internal plumbing, which was a little more intrusive than what was necessary for h/s/g/cp. It wasn't difficult, but I decided against the changes as I could not troubleshoot - there weren't any errors on macOS.

PS: New CI failures are unrelated to changes in this PR. It appears that boost downloads from JFrog are currently not working, which may or may not resolve. A workaround may involve downloading assets from GH boostorg.

[speth]

Thanks, @ischoegl, this looks good to me.