{"action":"created","issue":{"url":"https://api.github.com/repos/ParmEd/ParmEd/issues/486","labels_url":"https://api.github.com/repos/ParmEd/ParmEd/issues/486/labels{/name}","comments_url":"https://api.github.com/repos/ParmEd/ParmEd/issues/486/comments","events_url":"https://api.github.com/repos/ParmEd/ParmEd/issues/486/events","html_url":"https://github.com/ParmEd/ParmEd/issues/486","id":120085440,"number":486,"title":"Add support for writing (and reading) ffxml files from OpenMM","user":{"login":"swails","id":779022,"avatar_url":"https://avatars.githubusercontent.com/u/779022?v=3","gravatar_id":"","url":"https://api.github.com/users/swails","html_url":"https://github.com/swails","followers_url":"https://api.github.com/users/swails/followers","following_url":"https://api.github.com/users/swails/following{/other_user}","gists_url":"https://api.github.com/users/swails/gists{/gist_id}","starred_url":"https://api.github.com/users/swails/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/swails/subscriptions","organizations_url":"https://api.github.com/users/swails/orgs","repos_url":"https://api.github.com/users/swails/repos","events_url":"https://api.github.com/users/swails/events{/privacy}","received_events_url":"https://api.github.com/users/swails/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":24,"created_at":"2015-12-03T03:11:00Z","updated_at":"2015-12-17T02:09:43Z","closed_at":null,"body":"See pandegroup/openmm#1281"},"comment":{"url":"https://api.github.com/repos/ParmEd/ParmEd/issues/comments/165315058","html_url":"https://github.com/ParmEd/ParmEd/issues/486#issuecomment-165315058","issue_url":"https://api.github.com/repos/ParmEd/ParmEd/issues/486","id":165315058,"user":{"login":"swails","id":779022,"avatar_url":"https://avatars.githubusercontent.com/u/779022?v=3","gravatar_id":"","url":"https://api.github.com/users/swails","html_url":"https://github.com/swails","followers_url":"https://api.github.com/users/swails/followers","following_url":"https://api.github.com/users/swails/following{/other_user}","gists_url":"https://api.github.com/users/swails/gists{/gist_id}","starred_url":"https://api.github.com/users/swails/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/swails/subscriptions","organizations_url":"https://api.github.com/users/swails/orgs","repos_url":"https://api.github.com/users/swails/repos","events_url":"https://api.github.com/users/swails/events{/privacy}","received_events_url":"https://api.github.com/users/swails/received_events","type":"User","site_admin":false},"created_at":"2015-12-17T02:09:43Z","updated_at":"2015-12-17T02:09:43Z","body":"Oh good point @rafwiewiora...\r\n\r\n> We may also want to divide up the parameters for the forcefield into one file, and the residue definitions into other files.\r\n\r\nI didn't have anything against this proposal before @rafwiewiora commented :).  But it's just a bug waiting to happen, believe me.  You never know when residue libraries will suddenly inherit new atom types for some of the atoms, since that's the only way Amber can currently tweak specific torsions (this is how ff14SB changed some side-chain torsions).  Ergo, if you mix amino12.lib with ff99SB, you will get the wrong force field.  Ditto for amino10.lib and ff14SB.  The residue template libraries and parameter databases are inexorably linked.  Making people load each separately is just a subtle bug waiting to happen.\r\n\r\nSplitting AAs and NAs is a fine proposal IMO.  I would avoid splitting residues and parameters, though.\r\n\r\n> your second paragraph: is this because the residue definitions with charges are very conserved between different FFs?\r\n\r\nActually, yes.  ff94 and ff14SB have *exactly* the same charges for every single atom of every single residue.  But atom types are different, meaning that the templates are not interchangeable."}}