New patch release 0.8.7 fixing passing a PC array > 1D to HI PC optimization

[hakonanes]

Description of the change

We cannot pass a 3-component projection center (PC) array with more than one dimension to EBSD.hough_indexing_optimize_pc(). This PR fixes this. Since it's a bug, I'll release the fix as a patch release 0.8.7 tomorrow Monday 24 July.

The previousy failing behavior is now tested.

The error raised is:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
Cell In[10], line 1
----> 1 det_ref = s_in.hough_indexing_optimize_pc(pc0=det.pc, indexer=indexer)
      3 print(det.pc - det_ref.pc)

File ~/checkouts/readthedocs.org/user_builds/kikuchipy/envs/646/lib/python3.11/site-packages/kikuchipy/signals/ebsd.py:1803, in EBSD.hough_indexing_optimize_pc(self, pc0, indexer, batch, method)
   1800 if self._lazy:  # pragma: no cover
   1801     patterns = patterns.rechunk({0: "auto", 1: -1, 2: -1})
-> 1803 pc = _optimize_pc(
   1804     pc0=pc0, patterns=patterns, indexer=indexer, batch=batch, method=method
   1805 )
   1807 if batch:
   1808     pc = pc.reshape(nav_shape + (3,))

File ~/checkouts/readthedocs.org/user_builds/kikuchipy/envs/646/lib/python3.11/site-packages/kikuchipy/indexing/_hough_indexing.py:411, in _optimize_pc(pc0, patterns, indexer, batch, method)
    409 else:
    410     from pyebsdindex.pcopt import optimize as optimize_func
--> 411 return optimize_func(pats=patterns, indexer=indexer, PC0=pc0, batch=batch)

File ~/checkouts/readthedocs.org/user_builds/kikuchipy/envs/646/lib/python3.11/site-packages/pyebsdindex/pcopt.py:119, in optimize(pats, indexer, PC0, batch)
    116     PC0 = PCtemp
    118 if not batch:
--> 119     PCopt = opt.minimize(
    120         _optfunction,
    121         PC0,
    122         args=(indexer, banddat),
    123         method="Nelder-Mead",
    124         options={"fatol": 0.00001}
    125     )
    126     PCoutRet = PCopt['x']
    127 else:

File ~/checkouts/readthedocs.org/user_builds/kikuchipy/envs/646/lib/python3.11/site-packages/scipy/optimize/_minimize.py:533, in minimize(fun, x0, args, method, jac, hess, hessp, bounds, constraints, tol, callback, options)
    530 x0 = np.atleast_1d(np.asarray(x0))
    532 if x0.ndim != 1:
--> 533     raise ValueError("'x0' must only have one dimension.")
    535 if x0.dtype.kind in np.typecodes["AllInteger"]:
    536     x0 = np.asarray(x0, dtype=float)

ValueError: 'x0' must only have one dimension.

It is seen in the docs built from #646: https://kikuchipy--646.org.readthedocs.build/en/646/tutorials/pc_calibration_moving_screen_technique.html.

Progress of the PR

• [n/a] Docstrings for all functions
• [x] Unit tests with pytest for all lines
• [x] Clean code style by running black via pre-commit

For reviewers

• [ ] The PR title is short, concise, and will make sense 1 year later.
• [ ] New functions are imported in corresponding __init__.py.
• [ ] New features, API changes, and deprecations are mentioned in the unreleased section in CHANGELOG.rst.
• [ ] New contributors are added to release.py, .zenodo.json and .all-contributorsrc with the table regenerated.

[hakonanes]

In the interest of time, I'll release this now.