René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Default legend behavior (loc='best') very slow for large amounts of data.","articleBody":"\u003c!--To help us understand and resolve your issue, please fill out the form to the best of your ability.--\u003e\r\n\u003c!--You can feel free to delete the sections that do not apply.--\u003e\r\n\r\n### Bug report\r\n\r\n**Plotting large amounts of data with legend is slow when legend is using `best` location.**\r\n\r\n\u003c!--A short 1-2 sentences that succinctly describes the bug--\u003e\r\n\r\n**Code for reproduction**\r\n\r\n\u003c!--A minimum code snippet required to reproduce the bug, also minimizing the number of dependencies required--\u003e\r\n\r\n```python\r\nimport numpy as np\r\nimport matplotlib.pyplot as plt\r\nimport matplotlib as mpl\r\n\r\n# Setup, and create the data to plot\r\ny = np.random.rand(10000000)\r\n# Adapted from https://matplotlib.org/tutorials/introductory/usage.html#performance\r\nmpl.rcParams['path.simplify'] = True\r\nmpl.rcParams['path.simplify_threshold'] = 1.0\r\n\r\nplt.plot(y, label='data')\r\nplt.legend(loc='best')\r\nplt.show()\r\n\r\nplt.plot(y, label='data')\r\nplt.legend(loc='upper right')\r\nplt.show()\r\n\r\n\r\n```\r\n\r\n**Actual outcome**\r\n\r\nThe first plot is much slower (`loc='best'`) than the second.\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: Ubuntu 18.04\r\n  * Matplotlib version: 2.1.x and 2.2.x\r\n  * Matplotlib backend (`print(matplotlib.get_backend())`): Qt5Agg, TkAgg\r\n  * Python version: 3.7\r\n  * Jupyter version (if applicable): N/A\r\n  * Other libraries: numpy 1.15.1\r\n\r\nInstalled via conda.\r\n\r\n--------------------------------------------\r\n\r\nI think it'd be fine to just note this in the performance section of the User Guide (https://matplotlib.org/tutorials/introductory/usage.html#performance). I could also try looking into speeding up the `best` location finder but I get the feeling that'd be a fairly slow project.\r\n\r\nCurious to hear what others think.","author":{"url":"https://github.com/kbrose","@type":"Person","name":"kbrose"},"datePublished":"2018-09-14T18:04:13.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":5},"url":"https://github.com/12120/matplotlib/issues/12120"}