restore functionality with array-like tth input

[joelvbernier]

A recent merge broke the ability to use instrument.HEDMInstrument.extract_line_positions() with array-like input for the plane_data arg. This PR restores that functionality. Some default values are also updated, noting that the 2theta tolerance is now in % difference, not absolute deg.

closes #441

[pep8speaks]

Hello @joelvbernier! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2022-05-13 08:26:57 UTC

[joelvbernier]

Checks out on Linux; seems to fail for mp_context=spawn however.

[joelvbernier]

@psavery -- confirmed that the attached problem fails when I try to run under the spawn context on Mac and WIndows. Runs fine under Linux/fork.
DCS_powder_cal_example.zip

[psavery]

I think you just need to change the last line in your script to something like this:

if __name__ == '__main__':
    import multiprocessing
    multiprocessing.freeze_support()
    pwdr_lines = instr.extract_line_positions(**kwargs)

See #441 for more details.

[psavery]

LGTM. It seems that the spawn multiprocessing issue you are encountering is to be fixed in the script, rather than in this PR.