{"action":"created","issue":{"url":"https://api.github.com/repos/Theano/Theano/issues/3319","labels_url":"https://api.github.com/repos/Theano/Theano/issues/3319/labels{/name}","comments_url":"https://api.github.com/repos/Theano/Theano/issues/3319/comments","events_url":"https://api.github.com/repos/Theano/Theano/issues/3319/events","html_url":"https://github.com/Theano/Theano/issues/3319","id":102570540,"number":3319,"title":"Graph contains cycles","user":{"login":"dselsam","id":4520285,"avatar_url":"https://avatars.githubusercontent.com/u/4520285?v=3","gravatar_id":"","url":"https://api.github.com/users/dselsam","html_url":"https://github.com/dselsam","followers_url":"https://api.github.com/users/dselsam/followers","following_url":"https://api.github.com/users/dselsam/following{/other_user}","gists_url":"https://api.github.com/users/dselsam/gists{/gist_id}","starred_url":"https://api.github.com/users/dselsam/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/dselsam/subscriptions","organizations_url":"https://api.github.com/users/dselsam/orgs","repos_url":"https://api.github.com/users/dselsam/repos","events_url":"https://api.github.com/users/dselsam/events{/privacy}","received_events_url":"https://api.github.com/users/dselsam/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":6,"created_at":"2015-08-22T22:13:03Z","updated_at":"2015-08-28T12:48:14Z","closed_at":null,"body":"Hi,\r\n\r\nWhen compiling my model, I get `ValueError(graph contains cycles)` during the check in `general_toposort`. The traceback is long, but the beginning is: \r\n\r\n```\r\nERROR (theano.gof.opt): SeqOptimizer apply \r\n<theano.gof.opt.EquilibriumOptimizer object at 0x21e49990>\r\n```\r\n\r\nMy model is a rather complicated recursive neural network, and unfortunately I cannot find a simple example that reproduces the error.\r\n\r\n1. Is it correct that no model should be able to trigger this error, and thus that it is a bug in Theano itself?\r\n2. If I sent my model and enough data to trigger the error, would a developer be willing to investigate?\r\n3. If not, are there any potential workarounds, at the user level or involving extra checks and roll-backs during the graph optimization?\r\n\r\nThanks very much.\r\n"},"comment":{"url":"https://api.github.com/repos/Theano/Theano/issues/comments/135766189","html_url":"https://github.com/Theano/Theano/issues/3319#issuecomment-135766189","issue_url":"https://api.github.com/repos/Theano/Theano/issues/3319","id":135766189,"user":{"login":"twiecki","id":674200,"avatar_url":"https://avatars.githubusercontent.com/u/674200?v=3","gravatar_id":"","url":"https://api.github.com/users/twiecki","html_url":"https://github.com/twiecki","followers_url":"https://api.github.com/users/twiecki/followers","following_url":"https://api.github.com/users/twiecki/following{/other_user}","gists_url":"https://api.github.com/users/twiecki/gists{/gist_id}","starred_url":"https://api.github.com/users/twiecki/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/twiecki/subscriptions","organizations_url":"https://api.github.com/users/twiecki/orgs","repos_url":"https://api.github.com/users/twiecki/repos","events_url":"https://api.github.com/users/twiecki/events{/privacy}","received_events_url":"https://api.github.com/users/twiecki/received_events","type":"User","site_admin":false},"created_at":"2015-08-28T12:48:14Z","updated_at":"2015-08-28T12:48:14Z","body":"I did a git bisect and found that this commit introduced the problem: https://github.com/Theano/Theano/commit/9685f1d1507cdea4df0aa93c46e3e0577af70b3e"}}