René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"The plot function of the matplotlib 2 and 3 versions is much slower than 1.5.3","articleBody":"### Bug report\r\n\r\n**Bug summary**\r\n\r\nThe plot function of the matplotlib 2 and 3 versions is much slower than the plot function of matplotlib 1.5.3 if one plots many lines (and other objects) in an Axes.\r\n\r\n**Code for reproduction**\r\n\r\nI have tested it on an Ubuntu server (CLI only), version 16.04 with python 3.5.2 (through virtualenv), matplotlib 1.5.3 with backend agg set by matplotlibrc. \r\n\r\n```python\r\nsetup=\"\"\"import matplotlib.pyplot as plt\r\na=[1,2]\"\"\"\r\ntest=\"plt.plot(a,a,'-')\"\r\nimport timeit\r\ntimeit.timeit(test,setup,number=1000)\r\n# output: 0.6324263589922339\r\ntimeit.timeit(test,setup,number=1000)\r\n# output: 0.6100882450118661\r\ntimeit.timeit(test,setup,number=1000)\r\n# output: 0.6113728249911219\r\n```\r\n=\u003e around 0.6-0.7 sec, it is stable for a few dozen times.\r\n\r\nOn the same machine \u0026 operating system, python 3.5.2 (through virtualenv), matplotlib 2.2.2 with backend agg. \r\n\r\n```python\r\nsetup=\"\"\"import matplotlib.pyplot as plt\r\na=[1,2]\"\"\"\r\ntest=\"plt.plot(a,a,'-')\"\r\nimport timeit\r\ntimeit.timeit(test,setup,number=1000)\r\n# output: 0.9981246230890974\r\ntimeit.timeit(test,setup,number=1000)\r\n# output: 1.3041282850317657\r\ntimeit.timeit(test,setup,number=1000)\r\n# output: 1.6257964670658112\r\ntimeit.timeit(test,setup,number=1000)\r\n# output: 1.9830634299432859\r\n```\r\n=\u003e getting slower and slower...\r\n\r\nNote that matplotlib 2.0.0, 2.0.1, 2.1.0, 2.1.2, 2.2.2, or 3.0.0 has the same slowdown behavior. If I set svg as backend, the result is the same as agg (I confirmed backend=\"svg\" only for matplotlib 2.0.0 on the Ubuntu server). \r\n\r\nThis behavior is also confirmed on a Windows distribution: WinPython-64bit-3.4.4.6Qt5 with matplotlib 2.0.0 and default backend TkAgg, but not for WinPython-64bit-3.4.4.5Qt5 with matplotlib version 1.5.3 and TkAgg, though the situation is much more complex. In addition, WinPython-64bit-3.5.1.1 and matplotlib 2.1.0 (packaged by Christoph Gohlke) causes the same slowdown behavior. \r\n\r\nAnother windows distribution anaconda 3 version 4.4.0(64bit) also has a similar behavior. For the anaconda 3 environment, all the packages are default of the 4.4.0 distribution (python 3.6 and matplotlib 2.0.2 with backend qt5agg), and it runs on windows7-x64. \r\n\r\nIf I close the figure by pyplot.close(), the slowed plot() is returned to the initial state. \r\n\r\n**Expected outcome**\r\n\r\nThe expected outcome is \"no slowdown for the plot function of matplotlib 3\" as the matplotlib version 1.5.3.\r\n\r\n**Matplotlib version**\r\n  * Operating system: Ubuntu 1604 (CLI only)\r\n  * Matplotlib version: matplotlib 2.2.2\r\n  * Matplotlib backend (`print(matplotlib.get_backend())`): agg\r\n  * Python version: 3.5.2\r\n  * Jupyter version (if applicable): \r\n  * Other libraries: \r\n\r\n**Other note**\r\n\r\nI have used a script to write huge maps with overlayed many lines drawn by plot(). When I'm with matplotlib 1.5.3, it takes several minutes to output a bunch of png files, but no fatal problem is there. However, with 2.0.0-3.0.0 it takes several hours or more, and I cannot use the script at all. \r\n\r\nI believe this slowdown behavior can occur for most of the matplotlib environments. I think this is not an OS/system dependent bug/specification. ","author":{"url":"https://github.com/materia9","@type":"Person","name":"materia9"},"datePublished":"2018-10-17T04:17:44.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":19},"url":"https://github.com/12542/matplotlib/issues/12542"}