benchmarking script

[jhdark]

Proposed changes

Performance benchmarking is a useful way to keep track of how updates to the code affect performance.

A benchmark script is proposed comparing the performance of a simulation of gas permeation in pure fenicsx and in festim. It can be run using;
python3 test/benchmark.py
If the performance of festim is more than 20% worse than the fenics script on average, the test will fail rasing an error:
ValueError: festim is {diff:.1f}% slower than fenics, current acceptble threshold of 20%

More sophisticated methods of continuous testing can be implemented in the future: https://github.com/ionelmc/pytest-benchmark.

Types of changes

What types of changes does your code introduce to FESTIM?

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Code refactoring
• Documentation Update (if none of the other choices apply)
• New tests

Checklist

• Black formatted
• Unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

If this is a relatively large or complex change, kick off the discussion by explaining why you chose the solution you did and what alternatives you considered, etc...

[codecov]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (2ce0c38) 95.88% compared to head (b9aab59) 95.89%.
Report is 7 commits behind head on fenicsx.

Additional details and impacted files

@@             Coverage Diff             @@
##           fenicsx     #607      +/-   ##
===========================================
+ Coverage    95.88%   95.89%   +0.01%     
===========================================
  Files           10       10              
  Lines          267      268       +1     
===========================================
+ Hits           256      257       +1     
  Misses          11       11              

Files	Coverage Δ
festim/hydrogen_transport_problem.py	97.52% <100.00%> (+0.02%)	⬆️

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[RemDelaporteMathurin]

I think this would be more useful if you had the action fail if the benchmark was higher than a certain value

[RemDelaporteMathurin]

• move the benchmark script to test
• change threshold

[RemDelaporteMathurin]

One small refactoring change and then good to merge!