{"action":"created","issue":{"url":"https://api.github.com/repos/luca-heltai/dealii/issues/90","repository_url":"https://api.github.com/repos/luca-heltai/dealii","labels_url":"https://api.github.com/repos/luca-heltai/dealii/issues/90/labels{/name}","comments_url":"https://api.github.com/repos/luca-heltai/dealii/issues/90/comments","events_url":"https://api.github.com/repos/luca-heltai/dealii/issues/90/events","html_url":"https://github.com/luca-heltai/dealii/pull/90","id":140144955,"number":90,"title":"Bug in ChartManifold (SphericalManifold as an example)","user":{"login":"luca-heltai","id":2919756,"avatar_url":"https://avatars.githubusercontent.com/u/2919756?v=3","gravatar_id":"","url":"https://api.github.com/users/luca-heltai","html_url":"https://github.com/luca-heltai","followers_url":"https://api.github.com/users/luca-heltai/followers","following_url":"https://api.github.com/users/luca-heltai/following{/other_user}","gists_url":"https://api.github.com/users/luca-heltai/gists{/gist_id}","starred_url":"https://api.github.com/users/luca-heltai/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/luca-heltai/subscriptions","organizations_url":"https://api.github.com/users/luca-heltai/orgs","repos_url":"https://api.github.com/users/luca-heltai/repos","events_url":"https://api.github.com/users/luca-heltai/events{/privacy}","received_events_url":"https://api.github.com/users/luca-heltai/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2016-03-11T10:09:42Z","updated_at":"2016-03-11T22:04:07Z","closed_at":null,"pull_request":{"url":"https://api.github.com/repos/luca-heltai/dealii/pulls/90","html_url":"https://github.com/luca-heltai/dealii/pull/90","diff_url":"https://github.com/luca-heltai/dealii/pull/90.diff","patch_url":"https://github.com/luca-heltai/dealii/pull/90.patch"},"body":"@bangerth\r\n\r\nThis bug is preventing mapping-manifold from working. I'm trying a fix, but I don't really understand why it is not working...\r\n\r\nThis is what's happening. If I create a face quadrature, and use `get_new_point` based on the face vertices, for each face, then I get the following nice picture.\r\n\r\n![face_quads](https://cloud.githubusercontent.com/assets/2919756/13699310/d93d9cae-e779-11e5-8a72-62846b6c61f4.png)\r\n\r\n\r\nIf instead, I project the face quadrature to the cell (this is what happens inside `Mapping`), the `get_new_point` is used with the vertices of the **cell**, not the vertices of the **faces**. Of course, the weights associated to opposite face vertices are always zero. However, the periodicity trick in this case fails (I don't understand why), and for the face that crosses the periodic boundary (the lower one), we go the longer way (i.e., as if the manifold was not periodic across 2*pi). Using the projected quadrature ends up with the following:\r\n\r\n![cell_quads](https://cloud.githubusercontent.com/assets/2919756/13699311/dd2764a8-e779-11e5-9a77-2d945a5fefeb.png)\r\n\r\n\r\nwhere the quadrature points on the lower face get distributed along the longer circular arc, ending up somewhere mixed with the other faces.\r\n\r\n\r\n"},"comment":{"url":"https://api.github.com/repos/luca-heltai/dealii/issues/comments/195571048","html_url":"https://github.com/luca-heltai/dealii/pull/90#issuecomment-195571048","issue_url":"https://api.github.com/repos/luca-heltai/dealii/issues/90","id":195571048,"user":{"login":"bangerth","id":7504421,"avatar_url":"https://avatars.githubusercontent.com/u/7504421?v=3","gravatar_id":"","url":"https://api.github.com/users/bangerth","html_url":"https://github.com/bangerth","followers_url":"https://api.github.com/users/bangerth/followers","following_url":"https://api.github.com/users/bangerth/following{/other_user}","gists_url":"https://api.github.com/users/bangerth/gists{/gist_id}","starred_url":"https://api.github.com/users/bangerth/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/bangerth/subscriptions","organizations_url":"https://api.github.com/users/bangerth/orgs","repos_url":"https://api.github.com/users/bangerth/repos","events_url":"https://api.github.com/users/bangerth/events{/privacy}","received_events_url":"https://api.github.com/users/bangerth/received_events","type":"User","site_admin":false},"created_at":"2016-03-11T22:04:07Z","updated_at":"2016-03-11T22:04:07Z","body":"So is this a case where we violate the condition that it must be possible to cover all points given to the new-point operation with a single chart?"}}