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[Bug]: matshow(..., fignum=...) broken #29540
Description
Bug summary
From Version 3.10.0, plt.matshow(..., fignum=...) is broken.
I tested against the last nightly release matplotlib-3.11.0.dev377+g6c5e3f3348, where it is still broken.
Code for reproduction
import numpy as np
import matplotlib.pyplot as plt
fig = plt.figure()
plt.matshow(np.random.random([3, 3]), fignum=fig.number)Actual outcome
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/wehandre/mambaforge/envs/temptest/lib/python3.12/site-packages/matplotlib/pyplot.py", line 2668, in matshow
fig = figure(fignum, figsize=figaspect(A))
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/wehandre/mambaforge/envs/temptest/lib/python3.12/site-packages/matplotlib/pyplot.py", line 1013, in figure
if any([figsize, dpi, facecolor, edgecolor, not frameon,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()
Expected outcome
No error
Additional information
The issue is, that figsize is a NumPy array, and thus cannot be used within any. figsize is the result of the function matplotlib.figure.figaspect. To my knowledge, previously, this returned a tuple, which can be evaluated as a boolean. The documentation still suggests that the result is a tuple. However, I don't see any changes to matshow or figaspect inspecting their blames.
Operating system
No response
Matplotlib Version
3.10.0
Matplotlib Backend
No response
Python version
3.12.8
Jupyter version
No response
Installation
pip
Activity
rcomer commentedon Jan 28, 2025
Thanks @DerWeh. It looks like
figaspecthas not changed for a long time, so we should probably just change the documentation and type hint on that to reflect that it returns an array.The warning that trips over this was added at #27992. The check there should be adjusted to account for the fact that some of the parameters could be arrays (colours could also potentially be 3- or 4-element arrays).
We do not want the warning to be thrown for this example, so
matshowshould not pass a figsize if the figure already exists.So I think this is three issues in one!