n_coeffs_deriv sorting

[thangleiter]

Internally operators are sorted by their identifiers, but there were no checks performed in PulseSequence.get_filter_function_derivative whether the n_coeffs_deriv parameter is sorted as such.

[thangleiter]

Actually I don't remember why the sorting is necessary. Maybe we can drop it?

[codecov]

Codecov Report

Merging #83 (ae1c89f) into master (e60bf5f) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #83      +/-   ##
==========================================
+ Coverage   97.13%   97.14%   +0.01%     
==========================================
  Files           9        9              
  Lines        2267     2278      +11     
  Branches      516      520       +4     
==========================================
+ Hits         2202     2213      +11     
  Misses         29       29              
  Partials       36       36              

Impacted Files	Coverage Δ
filter_functions/gradient.py	100.00% <100.00%> (ø)
filter_functions/pulse_sequence.py	97.72% <100.00%> (+0.04%)	⬆️

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[JDTeske]

The previous sorting was required to comply with the order of control terms.

The derivatives have three axes [time, control, noise].
We fixed the order of the control terms but not the order of the noise terms.

[JDTeske]

The changes make sense to me and they fix the order of noise hamiltonians as required.

[thangleiter]

The previous sorting was required to comply with the order of control terms.

The derivatives have three axes [time, control, noise]. We fixed the order of the control terms but not the order of the noise terms.

I meant the sorting in general. Why they are stored sorted in the first place. I'll have to think about it, but that can wait. This should work for now.