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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"pcolormesh throws UFuncTypeError if np.datetime64() and shading='nearest","articleBody":"### Bug report\r\n\r\n**Bug summary**\r\n\r\nFor people who use numpy.datetime64() arrays with pcolormesh, a DeprecationWarning has been appearing prompting users to specify a shading kwarg 'nearest', 'auto' or 'gouraud' since shading='flat' is being deprecated. However, passing 'nearest' results in a UFuncTypeError when using 'nearest' due to a casting issue in _axes.py from _interp_grid()\r\n\r\n**Code for reproduction**\r\n```python\r\nimport numpy as np\r\nimport matplotlib.pyplot as plt\r\n\r\ntimes = np.arange(np.datetime64('2020-12-01'), np.datetime64('2020-12-31'))\r\nyaxis = np.arange(0, 20)\r\ncaxis = np.random.normal(0.0, 1.0, (times.shape[0], yaxis.shape[0]))\r\n\r\nplt.pcolormesh(times, yaxis, caxis.T, shading='nearest')\r\nplt.show()\r\n```\r\n\r\n**Actual outcome**\r\n```\r\nTraceback (most recent call last):\r\n\r\n  File \"..\\test.py\", line 15, in \u003cmodule\u003e\r\n    plt.pcolormesh(times, yaxis, caxis.T, shading='nearest')\r\n\r\n  File \"C:\\Users\\iarey\\anaconda3\\lib\\site-packages\\matplotlib\\pyplot.py\", line 2801, in pcolormesh\r\n    __ret = gca().pcolormesh(\r\n\r\n  File \"C:\\Users\\iarey\\anaconda3\\lib\\site-packages\\matplotlib\\__init__.py\", line 1438, in inner\r\n    return func(ax, *map(sanitize_sequence, args), **kwargs)\r\n\r\n  File \"C:\\Users\\iarey\\anaconda3\\lib\\site-packages\\matplotlib\\axes\\_axes.py\", line 6093, in pcolormesh\r\n    X, Y, C, shading = self._pcolorargs('pcolormesh', *args,\r\n\r\n  File \"C:\\Users\\iarey\\anaconda3\\lib\\site-packages\\matplotlib\\axes\\_axes.py\", line 5651, in _pcolorargs\r\n    X = _interp_grid(X)\r\n\r\n  File \"C:\\Users\\iarey\\anaconda3\\lib\\site-packages\\matplotlib\\axes\\_axes.py\", line 5633, in _interp_grid\r\n    if not (np.all(dX \u003e= 0) or np.all(dX \u003c= 0)):\r\n\r\nUFuncTypeError: Cannot cast ufunc 'greater_equal' input 0 from dtype('\u003cm8[D]') to dtype('\u003cm8') with casting rule 'same_kind'\r\n```\r\n\r\n**Expected outcome**\r\nA pcolormesh timeseries plot with random data and a np.datetime64() x-axis.\r\n\r\n**Matplotlib version**\r\n\u003c!--Please specify your platform and versions of the relevant libraries you are using:--\u003e\r\n  * Operating system: Windows 10\r\n  * Matplotlib version: 3.3.2 via standard conda\r\n  * Matplotlib backend: Qt5Agg\r\n  * Python version: 3.8.5\r\n  * Jupyter version (if applicable):\r\n  * Other libraries: numpy-1.19.2","author":{"url":"https://github.com/Yoshi2112","@type":"Person","name":"Yoshi2112"},"datePublished":"2020-12-29T10:57:36.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/19191/matplotlib/issues/19191"}