{"action":"created","issue":{"url":"https://api.github.com/repos/sympy/sympy/issues/4719","repository_url":"https://api.github.com/repos/sympy/sympy","labels_url":"https://api.github.com/repos/sympy/sympy/issues/4719/labels{/name}","comments_url":"https://api.github.com/repos/sympy/sympy/issues/4719/comments","events_url":"https://api.github.com/repos/sympy/sympy/issues/4719/events","html_url":"https://github.com/sympy/sympy/issues/4719","id":28950051,"node_id":"MDU6SXNzdWUyODk1MDA1MQ==","number":4719,"title":"Derivative operator","user":{"login":"asmeurer","id":71486,"node_id":"MDQ6VXNlcjcxNDg2","avatar_url":"https://avatars3.githubusercontent.com/u/71486?v=4","gravatar_id":"","url":"https://api.github.com/users/asmeurer","html_url":"https://github.com/asmeurer","followers_url":"https://api.github.com/users/asmeurer/followers","following_url":"https://api.github.com/users/asmeurer/following{/other_user}","gists_url":"https://api.github.com/users/asmeurer/gists{/gist_id}","starred_url":"https://api.github.com/users/asmeurer/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/asmeurer/subscriptions","organizations_url":"https://api.github.com/users/asmeurer/orgs","repos_url":"https://api.github.com/users/asmeurer/repos","events_url":"https://api.github.com/users/asmeurer/events{/privacy}","received_events_url":"https://api.github.com/users/asmeurer/received_events","type":"User","site_admin":false},"labels":[{"id":84627344,"node_id":"MDU6TGFiZWw4NDYyNzM0NA==","url":"https://api.github.com/repos/sympy/sympy/labels/bug","name":"bug","color":"ededed","default":true},{"id":84627341,"node_id":"MDU6TGFiZWw4NDYyNzM0MQ==","url":"https://api.github.com/repos/sympy/sympy/labels/imported","name":"imported","color":"ededed","default":false},{"id":84627345,"node_id":"MDU6TGFiZWw4NDYyNzM0NQ==","url":"https://api.github.com/repos/sympy/sympy/labels/valid","name":"valid","color":"d4c5f9","default":false}],"state":"open","locked":false,"assignee":{"login":"asmeurer","id":71486,"node_id":"MDQ6VXNlcjcxNDg2","avatar_url":"https://avatars3.githubusercontent.com/u/71486?v=4","gravatar_id":"","url":"https://api.github.com/users/asmeurer","html_url":"https://github.com/asmeurer","followers_url":"https://api.github.com/users/asmeurer/followers","following_url":"https://api.github.com/users/asmeurer/following{/other_user}","gists_url":"https://api.github.com/users/asmeurer/gists{/gist_id}","starred_url":"https://api.github.com/users/asmeurer/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/asmeurer/subscriptions","organizations_url":"https://api.github.com/users/asmeurer/orgs","repos_url":"https://api.github.com/users/asmeurer/repos","events_url":"https://api.github.com/users/asmeurer/events{/privacy}","received_events_url":"https://api.github.com/users/asmeurer/received_events","type":"User","site_admin":false},"assignees":[{"login":"asmeurer","id":71486,"node_id":"MDQ6VXNlcjcxNDg2","avatar_url":"https://avatars3.githubusercontent.com/u/71486?v=4","gravatar_id":"","url":"https://api.github.com/users/asmeurer","html_url":"https://github.com/asmeurer","followers_url":"https://api.github.com/users/asmeurer/followers","following_url":"https://api.github.com/users/asmeurer/following{/other_user}","gists_url":"https://api.github.com/users/asmeurer/gists{/gist_id}","starred_url":"https://api.github.com/users/asmeurer/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/asmeurer/subscriptions","organizations_url":"https://api.github.com/users/asmeurer/orgs","repos_url":"https://api.github.com/users/asmeurer/repos","events_url":"https://api.github.com/users/asmeurer/events{/privacy}","received_events_url":"https://api.github.com/users/asmeurer/received_events","type":"User","site_admin":false}],"milestone":null,"comments":59,"created_at":"2009-08-29T10:19:50Z","updated_at":"2018-10-09T14:29:15Z","closed_at":null,"author_association":"MEMBER","body":"```\nMost CAS's let you represent things like f(0), f'(0), f''(0), and so on, but SymPy only has support for \nthe first.  We should enable an option in the derivative of a function evaluated at a point.  I don't \nknow what the best syntax would be, probably some argument to diff, like point = 0, or point = (1, \n2, 3) for something like f'(1, 2, 3).  Not much would need to be implemented.  You just need a way \nto access the point in the Derivative class and Derivative needs to know to subs the point if it is \nevaluated.\n```\n\nOriginal issue for #4719: http://code.google.com/p/sympy/issues/detail?id=1620\nOriginal author: https://code.google.com/u/asmeurer@gmail.com/\nReferenced issues: #3696, #4720, #4759\nOriginal owner: https://code.google.com/u/asmeurer@gmail.com/\n"},"comment":{"url":"https://api.github.com/repos/sympy/sympy/issues/comments/428214557","html_url":"https://github.com/sympy/sympy/issues/4719#issuecomment-428214557","issue_url":"https://api.github.com/repos/sympy/sympy/issues/4719","id":428214557,"node_id":"MDEyOklzc3VlQ29tbWVudDQyODIxNDU1Nw==","user":{"login":"smichr","id":90703,"node_id":"MDQ6VXNlcjkwNzAz","avatar_url":"https://avatars3.githubusercontent.com/u/90703?v=4","gravatar_id":"","url":"https://api.github.com/users/smichr","html_url":"https://github.com/smichr","followers_url":"https://api.github.com/users/smichr/followers","following_url":"https://api.github.com/users/smichr/following{/other_user}","gists_url":"https://api.github.com/users/smichr/gists{/gist_id}","starred_url":"https://api.github.com/users/smichr/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/smichr/subscriptions","organizations_url":"https://api.github.com/users/smichr/orgs","repos_url":"https://api.github.com/users/smichr/repos","events_url":"https://api.github.com/users/smichr/events{/privacy}","received_events_url":"https://api.github.com/users/smichr/received_events","type":"User","site_admin":false},"created_at":"2018-10-09T14:29:15Z","updated_at":"2018-10-09T14:29:15Z","author_association":"MEMBER","body":"> result is incorrect when the function f contains x0 as a parameter\r\n\r\nDeclare that what you said is true -- declare `f` as having the parameters `x` and `x0` -- and you will get the desired result:\r\n\r\n```python\r\n>>> f(x).diff(x).subs(f(x), f(x, x0)).subs(x, x0)\r\nSubs(Derivative(f(x, x0), x), x, x0)\r\n```\r\nIf it's too complicated to make a simple substitution like that you can use replace to add `x0` to all args of `f`:\r\n```python\r\n>>> f(x).diff(x).replace(\r\n... lambda x: x.func ==f,\r\n... lambda x: x.func(*(x.args+(x0,))))\r\n...\r\nDerivative(f(x, x0), x)\r\n```\r\nDo either of those work for you?\r\n"}}
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