{"action":"created","issue":{"url":"https://api.github.com/repos/HazyResearch/sampler/issues/49","repository_url":"https://api.github.com/repos/HazyResearch/sampler","labels_url":"https://api.github.com/repos/HazyResearch/sampler/issues/49/labels{/name}","comments_url":"https://api.github.com/repos/HazyResearch/sampler/issues/49/comments","events_url":"https://api.github.com/repos/HazyResearch/sampler/issues/49/events","html_url":"https://github.com/HazyResearch/sampler/issues/49","id":173099770,"number":49,"title":"learn_non_evidence flag issue","user":{"login":"thodrek","id":1043311,"avatar_url":"https://avatars.githubusercontent.com/u/1043311?v=3","gravatar_id":"","url":"https://api.github.com/users/thodrek","html_url":"https://github.com/thodrek","followers_url":"https://api.github.com/users/thodrek/followers","following_url":"https://api.github.com/users/thodrek/following{/other_user}","gists_url":"https://api.github.com/users/thodrek/gists{/gist_id}","starred_url":"https://api.github.com/users/thodrek/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/thodrek/subscriptions","organizations_url":"https://api.github.com/users/thodrek/orgs","repos_url":"https://api.github.com/users/thodrek/repos","events_url":"https://api.github.com/users/thodrek/events{/privacy}","received_events_url":"https://api.github.com/users/thodrek/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/HazyResearch/sampler/labels/bug","name":"bug","color":"fc2929"},{"url":"https://api.github.com/repos/HazyResearch/sampler/labels/question","name":"question","color":"cc317c"}],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":2,"created_at":"2016-08-25T02:19:57Z","updated_at":"2016-08-25T03:00:33Z","closed_at":null,"body":"@netj @alldefector Check lines 138 - 141 in gibbs_sampler.h  For non-evidence and non-observation variables the same proposal value is assigned to both infrs.assignments_free and infrs.assignments_evid. If no other variable in a potential that this variable touches changes (e.g., single-threaded execution) then the gradient will be zero. This means that effectively learn_non_evidence does nothing. Compare with the old dimmwitted code: two separate samples are assigned to infrs.assignments_free  and infrs.assignments_evid.\r\n"},"comment":{"url":"https://api.github.com/repos/HazyResearch/sampler/issues/comments/242268821","html_url":"https://github.com/HazyResearch/sampler/issues/49#issuecomment-242268821","issue_url":"https://api.github.com/repos/HazyResearch/sampler/issues/49","id":242268821,"user":{"login":"thodrek","id":1043311,"avatar_url":"https://avatars.githubusercontent.com/u/1043311?v=3","gravatar_id":"","url":"https://api.github.com/users/thodrek","html_url":"https://github.com/thodrek","followers_url":"https://api.github.com/users/thodrek/followers","following_url":"https://api.github.com/users/thodrek/following{/other_user}","gists_url":"https://api.github.com/users/thodrek/gists{/gist_id}","starred_url":"https://api.github.com/users/thodrek/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/thodrek/subscriptions","organizations_url":"https://api.github.com/users/thodrek/orgs","repos_url":"https://api.github.com/users/thodrek/repos","events_url":"https://api.github.com/users/thodrek/events{/privacy}","received_events_url":"https://api.github.com/users/thodrek/received_events","type":"User","site_admin":false},"created_at":"2016-08-25T03:00:33Z","updated_at":"2016-08-25T03:00:33Z","body":"This can be used for maximum likelihood estimation in latent variable models. You can leverage the presence of observations\r\nfor parameter learning. To me what the sampler does during learning in that case (if you have learn_non_evidence on) is execute\r\nsomething similar to the expectation-conjugate gradient algorithm which under certain conditions corresponds to EM.\r\n\r\nNew projects such as data programming could potentially benefit from that option.\r\n\r\nOn Aug 24, 2016, at 7:51 PM, alldefector <notifications@github.com<mailto:notifications@github.com>> wrote:\r\n\r\n\r\nOK, we can fix it by generating and using a second proposal if learn_non_evidence and !variable.is<http://variable.is>_evid. Out curiosity, when do people usually turn on learn_non_evidence and what's its advantage?\r\n\r\n—\r\nYou are receiving this because you authored the thread.\r\nReply to this email directly, view it on GitHub<https://github.com/HazyResearch/sampler/issues/49#issuecomment-242267656>, or mute the thread<https://github.com/notifications/unsubscribe-auth/AA_rbwstzNANqHuBofL1cdXDOgafWk6aks5qjQMcgaJpZM4Jsoca>.\r\n\r\n"}}
{"actor":{"display_login":"thodrek"}}