fixed span derivative issues

[joanibal]

Purpose

This PR addresses this issues and issues like it.

Simple design variable functions like this were producing the wrong derivative values because the coefficients used the second time (in the CS used to compute the Jacobain) had already been scaled once.

def span(val, geo):
    C = geo.extractCoef("wing")
    for i in range(1, nRefAxPts):
        C[i, 2] *= val
    geo.restoreCoef(C, "wing")

The fix was simply to reset the FFD coefficient values before the CS loop used to calculate the Jacobian.

Expected time until merged

1 week

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

See the new test

Checklist

• I have run flake8 and black to make sure the code adheres to PEP-8 and is consistently formatted
• 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

Merging #143 (aaddcb3) into main (53494a8) will decrease coverage by 10.85%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##             main     #143       +/-   ##
===========================================
- Coverage   62.77%   51.91%   -10.86%     
===========================================
  Files          46       46               
  Lines       11263    11266        +3     
===========================================
- Hits         7070     5849     -1221     
- Misses       4193     5417     +1224     

Impacted Files	Coverage Δ
pygeo/parameterization/DVGeo.py	63.96% <100.00%> (-0.45%)	⬇️
pygeo/parameterization/DVGeoMulti.py	0.40% <0.00%> (-89.42%)	⬇️
pygeo/constraints/areaConstraint.py	50.50% <0.00%> (-25.42%)	⬇️
pygeo/constraints/DVCon.py	68.04% <0.00%> (-3.69%)	⬇️
pygeo/pyBlock.py	45.37% <0.00%> (-1.65%)	⬇️
pygeo/topology.py	54.92% <0.00%> (-0.23%)	⬇️
pygeo/__init__.py	100.00% <0.00%> (+10.52%)	⬆️
pygeo/parameterization/__init__.py	100.00% <0.00%> (+14.28%)	⬆️

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[marcomangano]

Why does the reset happen only if the FFD is not a child?

[joanibal]

If the FFD is child then it's nodes will be moved by the parent

[joanibal]

Without this the test_block test were failing

[marcomangano]

does that work even if I define the span variable directly on the child?

[joanibal]

I'm not sure.
Probably not

[joanibal]

I have added a test using a span variable on a child FFD.
It looks like it worked

[joanibal]

@hajdik This is ready for review again

[marcomangano]

Thanks for adding the extra test!