{"action":"opened","issue":{"url":"https://api.github.com/repos/sympy/sympy/issues/9859","labels_url":"https://api.github.com/repos/sympy/sympy/issues/9859/labels{/name}","comments_url":"https://api.github.com/repos/sympy/sympy/issues/9859/comments","events_url":"https://api.github.com/repos/sympy/sympy/issues/9859/events","html_url":"https://github.com/sympy/sympy/issues/9859","id":103042115,"number":9859,"title":"[diffgeom] Trouble with base_oneform for non cartesian coordinates system","user":{"login":"FabricioS","id":288230,"avatar_url":"https://avatars.githubusercontent.com/u/288230?v=3","gravatar_id":"","url":"https://api.github.com/users/FabricioS","html_url":"https://github.com/FabricioS","followers_url":"https://api.github.com/users/FabricioS/followers","following_url":"https://api.github.com/users/FabricioS/following{/other_user}","gists_url":"https://api.github.com/users/FabricioS/gists{/gist_id}","starred_url":"https://api.github.com/users/FabricioS/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/FabricioS/subscriptions","organizations_url":"https://api.github.com/users/FabricioS/orgs","repos_url":"https://api.github.com/users/FabricioS/repos","events_url":"https://api.github.com/users/FabricioS/events{/privacy}","received_events_url":"https://api.github.com/users/FabricioS/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-08-25T15:03:43Z","updated_at":"2015-08-25T15:03:43Z","closed_at":null,"body":"I was trying to perform some computation on fields defined in cylindrical coordinates when I got caught by this puzzling behaviour. \r\n```python\r\nfrom sympy.diffgeom import *\r\nfrom sympy.diffgeom.rn import R2_p\r\nprint(R2_p.dtheta(R2_p.e_r))\r\n```\r\ngives 0 which is wrong as de_r/dtheta should be e_theta.\r\nI may have confused by the documentation but it seems to it does not account for the change in the base vectors depending on the coordinates."}}