RZ stopping criteria

[ejpaul]

This pull request implements new StoppingCriteria based on minimum and maximum values of the cylindrical R and Z coordinates. This is more convenient to use for creating Poincare plots of very compact configurations, for which the definition of a bounding surface may be challenging. The new classes are called RStoppingCriteria and ZStoppingCriteria, which are defined by the critical value of R or Z and a boolean that indicates whether the minimum or maximum is evaluated. The MinToroidalFluxStoppingCriteria and MaxToroidalFluxStoppingCriteria have been replaced by ToroidalFluxStoppingCriteria to mimic this structure.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (50f41d6) 91.43% compared to head (01aac45) 91.44%.
Report is 2 commits behind head on master.

Additional details and impacted files

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  Misses       1088     1088           

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unittests	91.44% <100.00%> (+<0.01%)	⬆️

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[landreman]

Kindly add a unit test in which RStoppingCriterion and ZStoppingCriterion are called.

[mbkumar]

My 2 cents:

Replacing MinToroidalFluxStoppingCriteria and MaxToroidalFluxStoppingCriteria with ToroidalFluxStoppingCriteria is breaking the existing API. I am not sure who is using this piece of code, but to favor the users, can you retain the previous two classes and call the ToroidalFluxStoppingCriteria behind the scenes whenever the user calls the [Max,Min]ToroidalFluxStoppingCriteria with a deprecation warning? Please make sure the existing tests are retained.

[ejpaul]

@mbkumar @landreman Thanks for your feedback. I have added a unit test to test_fieldline.py, and I have reverted to the previous API.