René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: ValueError (\"cannot convert float NaN to integer\") when trying to show horizontally-stacked subplots","articleBody":"### Bug summary\n\nShowing two horizontally-stacked subplots with a shared y axis and per-subplot titles fails if the y values are too large. This is a regression in matplotlib 3.11.0; it worked in 3.10.9.\n\n### Code for reproduction\n\n```Python\nfig, axes = plt.subplots(1,2, figsize=(12,5), sharey=True, tight_layout=True)\n\nx = list(range(10))\ny = [1e53 for _ in x]\n\nfor i, ax in enumerate(axes):\n    ax.set_title(f'Subplot {i}')\n    ax.plot(x,y)\n\nplt.show()\n```\n\n### Actual outcome\n\n```\nTraceback (most recent call last):\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/backend_bases.py\", line 1165, in _on_timer\n    ret = func(*args, **kwargs)\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/backends/backend_macosx.py\", line 71, in callback_func\n    callback()\n    ~~~~~~~~^^\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/backends/backend_macosx.py\", line 93, in _draw_idle\n    self.draw()\n    ~~~~~~~~~^^\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/backends/backend_macosx.py\", line 56, in draw\n    super().draw()\n    ~~~~~~~~~~~~^^\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/backends/backend_agg.py\", line 438, in draw\n    self.figure.draw(self.renderer)\n    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/artist.py\", line 94, in draw_wrapper\n    result = draw(artist, renderer, *args, **kwargs)\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/artist.py\", line 71, in draw_wrapper\n    return draw(artist, renderer)\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/figure.py\", line 3282, in draw\n    mimage._draw_list_compositing_images(\n    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^\n        renderer, self, artists, self.suppressComposite)\n        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/image.py\", line 133, in _draw_list_compositing_images\n    a.draw(renderer)\n    ~~~~~~^^^^^^^^^^\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/artist.py\", line 71, in draw_wrapper\n    return draw(artist, renderer)\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/axes/_base.py\", line 3314, in draw\n    self._update_title_position(renderer)\n    ~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/axes/_base.py\", line 3258, in _update_title_position\n    ax.yaxis.get_tightbbox(renderer)  # update offsetText\n    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/axis.py\", line 1425, in get_tightbbox\n    ticks_to_draw = self._update_ticks()\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/axis.py\", line 1344, in _update_ticks\n    major_locs = self.get_majorticklocs()\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/axis.py\", line 1673, in get_majorticklocs\n    return self.major.locator()\n           ~~~~~~~~~~~~~~~~~~^^\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/ticker.py\", line 2299, in __call__\n    return self.tick_values(vmin, vmax)\n           ~~~~~~~~~~~~~~~~^^^^^^^^^^^^\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/ticker.py\", line 2307, in tick_values\n    locs = self._raw_ticks(vmin, vmax)\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/ticker.py\", line 2237, in _raw_ticks\n    nbins = np.clip(self.axis.get_tick_space(),\n                    ~~~~~~~~~~~~~~~~~~~~~~~~^^\n  File \"/opt/miniconda3/envs/snewpy/lib/python3.13/site-packages/matplotlib/axis.py\", line 2984, in get_tick_space\n    return int(np.floor(length / size))\nValueError: cannot convert float NaN to integer\n```\n\n### Expected outcome\n\nA plot with two (very boring) subplots; as in the following example generated with matplotlib 3.10.9:\n\u003cimg width=\"1312\" height=\"676\" alt=\"Image\" src=\"https://github.com/user-attachments/assets/991d0bdd-8764-4a7e-bcc4-71290873c964\" /\u003e\n\n### Additional information\n\nThe bug only seems to happen if three factors come together:\n* `y` becomes large enough to require scientific notation, with the `1e53` part shown at the top of the y axis. (When changing the code to `y = [1e2 for _ in x]`, the error disappears.)\n* A title is set for `axes[1]`. (When changing the code to `if i ==0: ax.set_title(f\"Subplot {i}\")`, the error disappears.)\n* The subplots are initialised with `sharey=True`. (When changing it to `False`, the error disappears.)\n\nThe same code has worked correctly in matplotlib 3.10.9 and earlier. (See “Expected Outcome” section.)\nI was also able to reproduce this bug on Ubuntu 24.04 in GitHub CI.\n\n### Operating system\n\nmacOS 15.7.7\n\n### Matplotlib Version\n\n3.11.0\n\n### Matplotlib Backend\n\nmacosx\n\n### Python version\n\n3.13.2\n\n### Jupyter version\n\n_No response_\n\n### Installation\n\npip","author":{"url":"https://github.com/JostMigenda","@type":"Person","name":"JostMigenda"},"datePublished":"2026-06-12T18:57:32.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/31881/matplotlib/issues/31881"}