Migrate from spmatrix to sparray

[gmmajal]

Since SciPy v1.15.0 https://github.com/scipy/scipy/releases/tag/v1.15.0 there is a new interface for the scipy.sparse module. From the release notes: “Sparse arrays are now fully functional for 1-D and 2-D arrays. We recommend that all new code use sparse arrays instead of sparse matrices and that developers start to migrate their existing code from sparse matrix to sparse array”.

A migration guide is provided here: https://docs.scipy.org/doc/scipy/reference/sparse.migration_to_sparray.html#migration-to-sparray

The files to consider are:
qualle/features/label_calibration/thesauri_label_calibration.py
qualle/features/combined.py
qualle/label_calibration/category.py
qualle/models.py

Also consider the unit tests for these scripts and modify if needed.