Fix evalFunctionsSens for projected area constraint

[A-CGray]

Purpose

The evalFunctionsSens method of the projected area constraint currently fails if it is called when there are no geometric design variables because only the creation of the dAp0/1/2 arrays are skipped, but the rest of the function, that uses those arrays, is not. This is fixed by simply skipping everything if nDV ==0.

Also:

• Altered the projected area constraint to allow for arbitrary projection directions (not just x,y,z)
• Made the sensitivity calculation marginally more efficient
• Split the box projected area test into one test that checks that the projected areas in the x y and z direction match the expected values, and another that tests the derivatives of the projected area in a random direction. The reason is that the sensitivities of the box's projected areas in the x, y and z directions are inaccurate due to the presence of surfaces perfectly orthogonal to the projection direction
• Added some comments in the code explaining this issue with the derivatives
• Switched from using np.random.seed and np.random.rand to np.random.default_rng and rng.random
• Re-trained DVConstraints tests due to new random numbers

Expected time until merged

Type of change

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (non-backwards-compatible fix or feature)
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Documentation update
• Maintenance update
• Other (please describe)

Testing

Checklist

• I have run flake8 and black to make sure the Python code adheres to PEP-8 and is consistently formatted
• I have formatted the Fortran code with fprettify or C/C++ code with clang-format as applicable
• I have run unit and regression tests which pass locally with my changes
• I have added new tests that prove my fix is effective or that my feature works
• I have added necessary documentation

[codecov]

Codecov Report

Attention: Patch coverage is 91.83673% with 4 lines in your changes missing coverage. Please review.

Project coverage is 65.41%. Comparing base (3070c1a) to head (8d199ad).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
pygeo/constraints/DVCon.py	73.33%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #253      +/-   ##
==========================================
- Coverage   65.42%   65.41%   -0.02%     
==========================================
  Files          47       47              
  Lines       12307    12315       +8     
==========================================
+ Hits         8052     8056       +4     
- Misses       4255     4259       +4     

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[marcomangano]

The changes make sense, but I wonder if it is more elegant to have something like:

if nDV == 0:
      pass

[A-CGray]

The changes make sense, but I wonder if it is more elegant to have something like:

if nDV == 0:
      pass

I don't think it matters, this solution would be 1 line longer than what's currently there.

[A-CGray]

@eytanadler so glad we figured this out so now you and @hajdik can get the mphys tests working :)

[eytanadler]

Excellent fixes, thank you @A-CGray (in particular for getting to the bottom of those derivatives!