René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"colorbar minorticks (possibly release critical for 3.0)","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**Bug summary**\r\n\r\n**NOTE: This is only applicable for 3.0 as cbar.minorticks_on() is introduced in 3.0 only.**\r\n\r\nWhen the minorticks are turned on for a colorbar, a minor tick is found to be missing from the vmax end of the colorbar (the weird part is, this doesn't happen for all values of vmax).\r\n\r\n@jklymak can you please have a look?\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\n\r\n# setup some generic data\r\nN = 37\r\nx, y = np.mgrid[:N, :N]\r\nZ = (np.cos(x*0.2) + np.sin(y*0.3))\r\n\r\nfig, ax= plt.subplots(figsize=(4, 3))\r\n\r\nim = ax.imshow(Z, cmap='RdBu', vmin=-1.2, vmax=1.2, interpolation='none')\r\ncbar = fig.colorbar(im, ax=ax, extend='both')\r\ncbar.minorticks_on()\r\nplt.show()\r\n```\r\n\r\n**Actual outcome**\r\n\r\n**The minor tick corresponding to the value +1.2 is missing!**\r\n\r\n![figure_1](https://user-images.githubusercontent.com/15175620/45337069-47b93300-b554-11e8-9d0f-ec4314217e8f.png)\r\n\r\n\r\n\r\nEven if I increase the vmax by 10**-16 I get the same result i.e.\r\n```python\r\nim = ax.imshow(Z, cmap='RdBu', vmin=-1.2, vmax=1.2+10**-16, interpolation='none')\r\n```\r\n\r\n**Expected outcome**\r\nI get the expected outcome by increasing the vmax by 10**-15\r\n```python\r\nim = ax.imshow(Z, cmap='RdBu', vmin=-1.2, vmax=1.2+10**-15, interpolation='none')\r\n```\r\n\r\n![figure_2](https://user-images.githubusercontent.com/15175620/45337077-4c7de700-b554-11e8-9aee-53d1cb050725.png)\r\n\r\n\r\n**This issue doesn't show up if I use  vmax=1.3**\r\n```python\r\nim = ax.imshow(Z, cmap='RdBu', vmin=-1.2, vmax=1.3, interpolation='none')\r\n```\r\n![figure_10](https://user-images.githubusercontent.com/15175620/45337306-4e947580-b555-11e8-88ee-3618c73d463e.png)\r\n\r\n\u003c!--A description of the expected outcome from the code snippet--\u003e\r\n\u003c!--If this used to work in an earlier version of Matplotlib, please note the version it used to work on--\u003e\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: Mac OS 10.13.6\r\n  * Matplotlib version:  '3.0.0rc2.post25+g68845f8e5'\r\n  * Matplotlib backend (`print(matplotlib.get_backend())`): Qt5Agg\r\n  * Python version: Python 3.7.0\r\n\r\n\r\nP.S. I realized this when I was looking at the modification I made to https://github.com/matplotlib/matplotlib/blob/master/examples/color/colorbar_basics.py to show off cbar.minorticks_on()","author":{"url":"https://github.com/pharshalp","@type":"Person","name":"pharshalp"},"datePublished":"2018-09-11T13:45:33.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/12095/matplotlib/issues/12095"}