Check unit order in UnitsSelectionSorting against the parent's ids

[h-mayorquin]

This is in the context of optimizations related to #4811. This s a single line change.

When looking at the memory used by rename_units I realized that the check added in #4581 to skip the np.lexsort when the order of the units is preserved never passes for a rename. It searches the renamed ids (self.unit_ids) in the parent ids, and as they are not there np.searchsorted returns the same position for every unit (array([2, 2]) for a rename of two units):

spikeinterface/src/spikeinterface/core/unitsselectionsorting.py

Lines 63 to 65 in 93c612f

	# check if order is preserved
	pos = np.searchsorted(self._parent_sorting.unit_ids, self.unit_ids)
	order_is_preserved = np.all(np.diff(pos) > 0)

Plus, np.searchsorted assumes that the parent ids are sorted. A selection that keeps the order of a parent with unsorted ids, string ids for example, also pays for the sort. This PR gets the positions with ids_to_indices(self._unit_ids) instead, and both cases now skip the sort.

[alejoe91]

Great catch!

[alejoe91]

LGTM! @grahamfindlay do you want to take a look?

other PR

[alejoe91]

@h-mayorquin actually this other PR #4783 removes that logic alltoghether

[samuelgarcia]

bravo

[h-mayorquin]

Yes, I am OK with having the other PR instead of this if they achieve the same.