MRG: fix Python 2, old Sympy stuff in derivations

[matthew-brett]

Python 2 prints, and older uses of Sympy.

Found while checking #910

[codecov]

Codecov Report

Merging #911 into master will decrease coverage by 0.08%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #911      +/-   ##
==========================================
- Coverage   91.81%   91.73%   -0.09%     
==========================================
  Files          97       97              
  Lines       12359    12359              
  Branches     2177     2177              
==========================================
- Hits        11348    11337      -11     
- Misses        678      684       +6     
- Partials      333      338       +5     

Impacted Files	Coverage Δ
nibabel/environment.py	75.00% <0.00%> (-20.00%)	⬇️
nibabel/casting.py	85.28% <0.00%> (-0.87%)	⬇️
nibabel/dft.py	80.36% <0.00%> (-0.62%)	⬇️
nibabel/nifti1.py	91.66% <0.00%> (-0.31%)	⬇️
nibabel/volumeutils.py	83.94% <0.00%> (-0.20%)	⬇️

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[jond01]

Hi, I suggest also changing slice_thickness and its occurrences here:

nibabel/doc/source/dicom/derivations/spm_dicom_orient.py

Line 40 in 8471a37

slice_thickness = Symbol('\Delta{s}')

To slice_spacing, in order to avoid confusion with the Slice Thickness dicom attribute.

[matthew-brett]

Good point, thanks.

[pep8speaks]

Hello @matthew-brett, Thank you for updating!

• In the file doc/source/dicom/derivations/spm_dicom_orient.py:

Line 56:9: E231 missing whitespace after ','
Line 61:10: E231 missing whitespace after ','
Line 72:1: E305 expected 2 blank lines after class or function definition, found 1
Line 77:9: E231 missing whitespace after ','
Line 77:33: E231 missing whitespace after ','
Line 77:35: E231 missing whitespace after ','
Line 143:1: E305 expected 2 blank lines after class or function definition, found 1

To test for issues locally, pip install flake8 and then run flake8 nibabel.

Comment last updated at 2020-05-25 09:32:47 UTC

[effigies]

The failing style check should be fixed in master. Mind hitting the PEP8 fixes requested by pep8speaks?

[matthew-brett]

I did a rebase to get rid of the PEP8 errors - but now get a coverage error - it must be a false positive.

[effigies]

Yeah, Codecov is overly sensitive. I'm okay to merge, if you're all set.

[matthew-brett]

All set.