Testing sources

[rstoneback]

Description

Adds support for pure dipole and linear quadrupole sources to verify performance of OMMBV on multipole sources.

Addresses a variety of issues, including documented issues #50, #44.

Provides direct evidence that vectors are orthogonal for multipole fields.

Original Performance

There is an apparent reduction in performance for some linear quadrupoles in the equatorial plane. Current uncertainty on scaling values for drifts and electric fields is < 0.1%. In practical terms, given instrumentation errors are certainly higher, the observed uncertainty is fine for scientific applications. Still, looking to see if there is a way to improve this performance. Scaling uncertainty for dipole and linear quadrupole (along pole) is < .001%.

UPDATE

Performance improved and uncertainty with multipole fields is the same as dipole alone! Fixes are in here. Also includes:

• docstring improvements
• code standard improvements
• deprecation warning improvements
• unit test overhaul
• code reduction
• bug fixes
• Documentation runs on RTD again
• Switch to setup.cfg
• Switch to GitHub Actions for testing

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New test feature (non-breaking change which adds functionality)

How Has This Been Tested?

Running unit tests on known source magnetic fields.

Test Configuration:

• MacOS
• Python 3.8

Checklist:

• [x] Make sure you are merging into the develop (not master) branch
• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [x] Any dependent changes have been merged and published in downstream modules
• [x] Add a note to CHANGELOG.md, summarizing the changes

[rstoneback]

I sorted out a bit of error and now the OMMBV vectors are even better. Uncertainty for multipole fields is at the same level as a pure dipole.

[rstoneback]

I'm giving up on windows testing. OMMBC appears to compile everything just fine. However, pytest tests the pure python code without the compiled and installed Fortran. I also dropped MacOS testing way back since there is no installed Fortran compiler on the machines. Runs locally on Mac.