{"action":"created","issue":{"url":"https://api.github.com/repos/bempp/bempp/issues/255","labels_url":"https://api.github.com/repos/bempp/bempp/issues/255/labels{/name}","comments_url":"https://api.github.com/repos/bempp/bempp/issues/255/comments","events_url":"https://api.github.com/repos/bempp/bempp/issues/255/events","html_url":"https://github.com/bempp/bempp/issues/255","id":118453833,"number":255,"title":"zero conditions on an open surface","user":{"login":"schulzho","id":15983513,"avatar_url":"https://avatars.githubusercontent.com/u/15983513?v=3","gravatar_id":"","url":"https://api.github.com/users/schulzho","html_url":"https://github.com/schulzho","followers_url":"https://api.github.com/users/schulzho/followers","following_url":"https://api.github.com/users/schulzho/following{/other_user}","gists_url":"https://api.github.com/users/schulzho/gists{/gist_id}","starred_url":"https://api.github.com/users/schulzho/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/schulzho/subscriptions","organizations_url":"https://api.github.com/users/schulzho/orgs","repos_url":"https://api.github.com/users/schulzho/repos","events_url":"https://api.github.com/users/schulzho/events{/privacy}","received_events_url":"https://api.github.com/users/schulzho/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":2,"created_at":"2015-11-23T19:28:25Z","updated_at":"2015-11-27T09:01:44Z","closed_at":null,"body":"Hello,\r\n\r\nI would like to have a piecewise polynomial subspace of $\\tilde H^\\frac12(\\Gamma)$\r\nof order 0 and 1 on a (flat) open surface $\\Gamma$. What is the best way to do\r\nthis in bem++? I tried (among other things)...\r\n\r\nspace = function_space(grid,\"P\",1, closed=False)\r\n\r\n... but it I did not observe the desired effect. I also found something about weights \r\nbetween local and global dofs, perhaps this is the right way? But how I can\r\nchange this weights?\r\n\r\nGreetings,\r\nHeiko"},"comment":{"url":"https://api.github.com/repos/bempp/bempp/issues/comments/160077519","html_url":"https://github.com/bempp/bempp/issues/255#issuecomment-160077519","issue_url":"https://api.github.com/repos/bempp/bempp/issues/255","id":160077519,"user":{"login":"schulzho","id":15983513,"avatar_url":"https://avatars.githubusercontent.com/u/15983513?v=3","gravatar_id":"","url":"https://api.github.com/users/schulzho","html_url":"https://github.com/schulzho","followers_url":"https://api.github.com/users/schulzho/followers","following_url":"https://api.github.com/users/schulzho/following{/other_user}","gists_url":"https://api.github.com/users/schulzho/gists{/gist_id}","starred_url":"https://api.github.com/users/schulzho/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/schulzho/subscriptions","organizations_url":"https://api.github.com/users/schulzho/orgs","repos_url":"https://api.github.com/users/schulzho/repos","events_url":"https://api.github.com/users/schulzho/events{/privacy}","received_events_url":"https://api.github.com/users/schulzho/received_events","type":"User","site_admin":false},"created_at":"2015-11-27T09:01:44Z","updated_at":"2015-11-27T09:01:44Z","body":"Dear Timo,\n\nFor physical reasons, I really need the zero conditions on the boundary curve.\n\nMoreover, I want to consider the hypersingular operator, so I have to be careful with the kernel of the mapping (D(1)=0).\n\nWould it be possible to split a function space generated by function_space(grid,\"P\",1) into subspaces? \n\nFor a simple test case (let's say, the unit circle) it is easy to determine the boundary nodes, so it would be nice to neglect the corresponding ansatz functions of the space or to split the space into a part corresponding to DOFs on the boundary and the \"rest\".\n\nAnother way around would be to introduce a projection from $H^\\frac12$ into $\\tilde H^\\frac12$ and to discretize this seperately from the hypersingular operator, i.e. to purge the corresponding lines and rows of the matrix. But for this I need direct access to the matrix structure.\n\nI am familiar with Python and C++, but in such a strong way as you and the bem++ team.\n\nBest wishes,\nHeiko\n\n\n\n\n\n\nOn Thu, Nov 26, 2015 at 01:05:29PM -0800, tbetcke wrote:\n> Dear Heiko,\n> \n> sorry for the late response. We have never considered the case of polynomial spaces on open surfaces. Piecewise constant spaces should automatically work fine. For Maxwell Raviart-Thomas spaces we also in the space initialization make sure that no dofs are set on the boundary of an open surface.\n> \n> Do you need linear spaces on open surfaces urgently or can you live with piecewise constant spaces on open surfaces for now? Implementing it may be an effort that would have to wait for a couple of weeks.\n> \n> Best wishes\n> \n> Timo\n> \n> ---\n> Reply to this email directly or view it on GitHub:\n> https://github.com/bempp/bempp/issues/255#issuecomment-159994010\n\n-- \n\nMit freundlichen Grüßen / with best regards\n\nDr. Heiko Schulz\nFachbereich Mathematik\nPfaffenwaldring 57\nRaum 8.313\nUniversität Stuttgart\n\nTel.   : (0711) 685 65344\nFax    : (0711) 685 65348\nE-Mail : schulz@mathematik.uni-stuttgart.de\n\nhttp://www.mathematik.uni-stuttgart.de/fachbereich/fachbereich/edv/schulz.html\n"}}