Add option to ignore inequality constraints in IncidenceGraphInterface

[Robbybp]

Summary/Motivation:

Often when analyzing an incidence matrix/graph, we are interested in the structure of equations and variables, and would like to exclude inequality constraints from the analysis. This can be done right now by passing equality constraints directly to the methods one wants to use, e.g. maximum_matching, but this is cumbersome. This PR adds an include_inequality flag to the constructor that, when False, only considers constraints whose expressions are instances of EqualityExpression.

Opened this PR as it has come to my attention that this might be useful. Marked WIP for now I haven't included a test for this functionality yet.

Legal Acknowledgement

By contributing to this software project, I have read the contribution guide and agree to the following terms and conditions for my contribution:

1. I agree my contributions are submitted under the BSD license.
2. I represent I am authorized to make the contributions and grant the license. If my employer has rights to intellectual property that includes these contributions, I represent that I have received permission to make contributions and grant the required license on behalf of that employer.

[michaelbynum]

Thanks @Robbybp!

[codecov]

Codecov Report

Merging #2350 (e844049) into main (30a60e0) will decrease coverage by 1.97%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #2350      +/-   ##
==========================================
- Coverage   85.83%   83.85%   -1.98%     
==========================================
  Files         617      617              
  Lines       75949    75952       +3     
==========================================
- Hits        65191    63693    -1498     
- Misses      10758    12259    +1501     

Flag	Coverage Δ
linux	79.02% <100.00%> (-3.62%)	⬇️
osx	72.85% <100.00%> (+<0.01%)	⬆️
other	79.19% <100.00%> (-3.63%)	⬇️
win	79.69% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pyomo/contrib/incidence_analysis/interface.py	98.20% <100.00%> (+0.03%)	⬆️
pyomo/contrib/pynumero/examples/parallel_matvec.py	0.00% <0.00%> (-96.43%)	⬇️
...o/contrib/pynumero/examples/parallel_vector_ops.py	0.00% <0.00%> (-95.84%)	⬇️
pyomo/contrib/pynumero/examples/mumps_example.py	15.00% <0.00%> (-82.50%)	⬇️
pyomo/contrib/pynumero/sparse/mpi_block_matrix.py	0.00% <0.00%> (-81.24%)	⬇️
pyomo/contrib/pynumero/sparse/mpi_block_vector.py	0.00% <0.00%> (-74.97%)	⬇️
pyomo/contrib/benders/benders_cuts.py	18.72% <0.00%> (-69.87%)	⬇️
pyomo/contrib/pynumero/linalg/mumps_interface.py	17.42% <0.00%> (-66.67%)	⬇️
...o/contrib/interior_point/linalg/mumps_interface.py	21.95% <0.00%> (-54.88%)	⬇️
pyomo/contrib/parmest/mpi_utils.py	47.42% <0.00%> (-27.84%)	⬇️
... and 6 more

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[Robbybp]

Removed WIP label. Ready for review/merge, assuming tests pass.

[Robbybp]

This changes behavior. Previously the nlp interface would always ignore inequalities, and the model interface would never ignore inequalities. This patch makes the two interfaces consistent (by default, include inequalities) and adds the option to ignore inequalities, which applies to both interface.

[Robbybp]

I'm not too worried about this because (a) this is contrib and (b) I'm not aware of anybody using the NLP interface.