René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: Matplotlib 3.5 breaks unyt integration of error bars","articleBody":"### Bug summary\r\n\r\nDiscovered this in unyt's daily CI jobs: https://github.com/yt-project/unyt/actions\r\n\r\n### Code for reproduction\r\n\r\n```python\r\nimport matplotlib.pyplot as plt\r\nimport unyt as un\r\n\r\nun.matplotlib_support.enable()\r\nfig, ax = plt.subplots()\r\n\r\nx = un.unyt_array([1, 2], \"cm\")\r\ny = un.unyt_array([3, 4], \"kg\")\r\nyerr = un.unyt_array([0.1, 0.2], \"kg\")\r\nax.errorbar(x, y, yerr=(yerr, yerr))\r\n```\r\n\r\n\r\n### Actual outcome\r\n\r\n```\r\nUnitOperationError: The \u003cufunc 'subtract'\u003e operator for unyt_arrays with units \"kg\" \r\n(dimensions \"(mass)\") and \"dimensionless\" (dimensions \"1\") is not well defined.\r\n```\r\n\r\n\u003cdetails\u003e \u003csummary\u003edetailed raceback\u003c/summary\u003e\r\n\r\n```\r\n╭──────────────────────────── Traceback (most recent call last) ────────────────────────────╮\r\n│                                                                                           │\r\n│ /private/tmp/matplotlib/t.py:10 in \u003cmodule\u003e                                               │\r\n│                                                                                           │\r\n│    7 x = un.unyt_array([1, 2], \"cm\")                                                      │\r\n│    8 y = un.unyt_array([3, 4], \"kg\")                                                      │\r\n│    9 yerr = un.unyt_array([0.1, 0.2], \"kg\")                                               │\r\n│ ❱ 10 ax.errorbar(x, y, yerr=yerr)                                                         │\r\n│   11                                                                                      │\r\n│ /private/tmp/matplotlib/lib/matplotlib/__init__.py:1348 in inner                          │\r\n│                                                                                           │\r\n│   1345 │   @functools.wraps(func)                                                         │\r\n│   1346 │   def inner(ax, *args, data=None, **kwargs):                                     │\r\n│   1347 │   │   if data is None:                                                           │\r\n│ ❱ 1348 │   │   │   return func(ax, *map(sanitize_sequence, args), **kwargs)               │\r\n│   1349 │   │                                                                              │\r\n│   1350 │   │   bound = new_sig.bind(ax, *args, **kwargs)                                  │\r\n│   1351 │   │   auto_label = (bound.arguments.get(label_namer)                             │\r\n│                                                                                           │\r\n│ /private/tmp/matplotlib/lib/matplotlib/axes/_axes.py:3474 in errorbar                     │\r\n│                                                                                           │\r\n│   3471 │   │   │   │   │   │   xo, yo, marker='|', **eb_cap_style))                       │\r\n│   3472 │   │                                                                              │\r\n│   3473 │   │   if yerr is not None:                                                       │\r\n│ ❱ 3474 │   │   │   lower, upper = extract_err('y', yerr, y, lolims, uplims)               │\r\n│   3475 │   │   │   barcols.append(self.vlines(                                            │\r\n│   3476 │   │   │   │   *apply_mask([x, lower, upper], everymask), **eb_lines_style))      │\r\n│   3477 │   │   │   # select points without upper/lower limits in y and                    │\r\n│                                                                                           │\r\n│ /private/tmp/matplotlib/lib/matplotlib/axes/_axes.py:3434 in extract_err                  │\r\n│                                                                                           │\r\n│   3431 │   │   │   │   │   f\"'{name}err' (shape: {np.shape(err)}) must be a scalar \"      │\r\n│   3432 │   │   │   │   │   f\"or a 1D or (2, n) array-like whose shape matches \"           │\r\n│   3433 │   │   │   │   │   f\"'{name}' (shape: {np.shape(data)})\") from None               │\r\n│ ❱ 3434 │   │   │   return data - low * ~lolims, data + high * ~uplims  # low, high        │\r\n│   3435 │   │                                                                              │\r\n│   3436 │   │   if xerr is not None:                                                       │\r\n│   3437 │   │   │   left, right = extract_err('x', xerr, x, xlolims, xuplims)              │\r\n│                                                                                           │\r\n│ /Users/robcleme/.pyenv/versions/3.9.7/envs/tmp_unit/lib/python3.9/site-packages/unyt/arra │\r\n│ y.py:1764 in __array_ufunc__                                                              │\r\n│                                                                                           │\r\n│   1761 │   │   │   │   │   │   │   │   else:                                              │\r\n│   1762 │   │   │   │   │   │   │   │   │   raise UnitOperationError(ufunc, u0, u1)        │\r\n│   1763 │   │   │   │   │   │   else:                                                      │\r\n│ ❱ 1764 │   │   │   │   │   │   │   raise UnitOperationError(ufunc, u0, u1)                │\r\n│   1765 │   │   │   │   │   conv, offset = u1.get_conversion_factor(u0, inp1.dtype)        │\r\n│   1766 │   │   │   │   │   new_dtype = np.dtype(\"f\" + str(inp1.dtype.itemsize))           │\r\n│   1767 │   │   │   │   │   conv = new_dtype.type(conv)                                    │\r\n╰───────────────────────────────────────────────────────────────────────────────────────────╯\r\nUnitOperationError: The \u003cufunc 'subtract'\u003e operator for unyt_arrays with units \"kg\" \r\n(dimensions \"(mass)\") and \"dimensionless\" (dimensions \"1\") is not well defined.\r\n```\r\n\r\n\u003c/details\u003e\r\n\r\n### Expected outcome\r\n\r\nThis is the output figure with matplotlib 3.4.3\r\n![unyt_err](https://user-images.githubusercontent.com/14075922/142433754-f33e94e9-0292-4faf-bddc-4f5e45150c3d.png)\r\n\r\n\r\n### Additional information\r\n\r\nThe regression bisects to #19526 (https://github.com/matplotlib/matplotlib/pull/19526/commits/8cd22b4d5840b08cd42f793f5a30e23595aa44f2)\r\n\r\nI note that if replace the last line with\r\n```\r\nax.errorbar(x, y, yerr=yerr)\r\n```\r\n(passing a single array instead of a tuple), it doesn't break on the main branch.\r\n\r\n### Operating system\r\n\r\nUnbuntu\r\n\r\n### Matplotlib Version\r\n\r\n3.5.0\r\n\r\n### Matplotlib Backend\r\n\r\nnot relevant (I get an identical error with the 'agg' backend)\r\n\r\n### Python version\r\n\r\ntested on 3.7 to 3.9\r\n\r\n### Jupyter version\r\n\r\n_No response_\r\n\r\n### Installation\r\n\r\npip","author":{"url":"https://github.com/neutrinoceros","@type":"Person","name":"neutrinoceros"},"datePublished":"2021-11-18T14:28:25.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":18},"url":"https://github.com/21669/matplotlib/issues/21669"}