[Mudassiruddin7]

Reference Issues/PRs

Fixes #1202.

What does this implement/fix? Explain your changes.

BaseDistribution._subset_param indexed every axis of a parameter by position. A parameter of shape (n_rows, 1) or (1, n_cols) is broadcast by the constructor, so for example Normal(mu=<2x3>, sigma=<2x1>).iloc[:, [2]] and .iat[1, 2] raised IndexError: there is no entry at position 2 on an axis of length 1.

An axis of length 1 is now repeated once per selected row or column, with a small helper _broadcast_index. Axes that are not of length 1 are indexed as before.

Does your contribution introduce a new dependency? If yes, which one?

No.

What should a reviewer concentrate their feedback on?

• _broadcast_index: it asks self.shape how many entries a selection picks from the axis, so that scalar, list, empty and repeated selections all give a parameter of the right size.

Did you add any tests for the change?

Yes, test_subset_broadcast_params.py. Five distributions with broadcast parameters (Normal with a sigma per row, per column, a mu per row with a sigma per column, a one-row mu, and Poisson with a mu per row), selected eight ways with iloc and iat. Each case compares the cdf of the selection, at a different point for every cell, with the same cells of the full distribution. There are also tests for empty selections and for a repeated row. 43 of the 50 cases fail on main, and the whole skpro/distributions test directory passes with the change (8640 passed, 6 skipped).

Any other comments?

• This also makes iat work for ZeroInflated and Hurdle with a per-row p. The scalar iloc crash in those two classes is a separate bug, [BUG] iloc with a scalar index raises TypeError for ZeroInflated and Hurdle #1201 / [BUG] handle scalar iloc indexers in ZeroInflated and Hurdle #1203.

PR checklist

For all contributions

• I've added myself to the list of contributors with any new badges I've earned :-)
• The PR title starts with either [ENH], [MNT], [DOC], or [BUG]. [BUG] - bugfix, [MNT] - CI, test framework, [ENH] - adding or improving code, [DOC] - writing or improving documentation or docstrings.

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