{"action":"created","issue":{"url":"https://api.github.com/repos/certik/theoretical-physics/issues/58","labels_url":"https://api.github.com/repos/certik/theoretical-physics/issues/58/labels{/name}","comments_url":"https://api.github.com/repos/certik/theoretical-physics/issues/58/comments","events_url":"https://api.github.com/repos/certik/theoretical-physics/issues/58/events","html_url":"https://github.com/certik/theoretical-physics/issues/58","id":116323130,"number":58,"title":"Derivation in section \"Total energy\" of DFT page is unclear","user":{"login":"RKBK","id":4726978,"avatar_url":"https://avatars.githubusercontent.com/u/4726978?v=3","gravatar_id":"","url":"https://api.github.com/users/RKBK","html_url":"https://github.com/RKBK","followers_url":"https://api.github.com/users/RKBK/followers","following_url":"https://api.github.com/users/RKBK/following{/other_user}","gists_url":"https://api.github.com/users/RKBK/gists{/gist_id}","starred_url":"https://api.github.com/users/RKBK/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/RKBK/subscriptions","organizations_url":"https://api.github.com/users/RKBK/orgs","repos_url":"https://api.github.com/users/RKBK/repos","events_url":"https://api.github.com/users/RKBK/events{/privacy}","received_events_url":"https://api.github.com/users/RKBK/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":2,"created_at":"2015-11-11T12:15:42Z","updated_at":"2015-11-12T15:25:24Z","closed_at":null,"body":"I've been reading the DFT page, and I'm trying to understand the section on the Total energy. A short bit into that section, it is written that \"If one is not careful about the potential associated with the eigenvalues, i.e., confusing V_{in} with V_{out}\". However, where is \"V_in\" and \"V_out\" defined? It is a bit unclear if the section is trying to explain what would happen if the equations given there are used to evaluated the total energy on each iteration of the KS solution. But why would the energy after an iteration be evaluated using the previous external potential (\"V_in\"?)? The message of the section is a bit unclear to me.\r\n\r\nFurthermore, the section seems to imply that the last equation of the section \"Total energy\" is somehow not preferable to a direct usage of the total energy expression (first equation of \"total energy\" section), despite the fact that several review works/text books on DFT indicate that the last expression is used in several DFT codes to calculate the total energy.\r\n"},"comment":{"url":"https://api.github.com/repos/certik/theoretical-physics/issues/comments/156137350","html_url":"https://github.com/certik/theoretical-physics/issues/58#issuecomment-156137350","issue_url":"https://api.github.com/repos/certik/theoretical-physics/issues/58","id":156137350,"user":{"login":"RKBK","id":4726978,"avatar_url":"https://avatars.githubusercontent.com/u/4726978?v=3","gravatar_id":"","url":"https://api.github.com/users/RKBK","html_url":"https://github.com/RKBK","followers_url":"https://api.github.com/users/RKBK/followers","following_url":"https://api.github.com/users/RKBK/following{/other_user}","gists_url":"https://api.github.com/users/RKBK/gists{/gist_id}","starred_url":"https://api.github.com/users/RKBK/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/RKBK/subscriptions","organizations_url":"https://api.github.com/users/RKBK/orgs","repos_url":"https://api.github.com/users/RKBK/repos","events_url":"https://api.github.com/users/RKBK/events{/privacy}","received_events_url":"https://api.github.com/users/RKBK/received_events","type":"User","site_admin":false},"created_at":"2015-11-12T15:25:24Z","updated_at":"2015-11-12T15:25:24Z","body":"Thank you, I would certainly appreciate a clarification."}}