{"action":"opened","issue":{"url":"https://api.github.com/repos/scikit-learn/scikit-learn/issues/4459","labels_url":"https://api.github.com/repos/scikit-learn/scikit-learn/issues/4459/labels{/name}","comments_url":"https://api.github.com/repos/scikit-learn/scikit-learn/issues/4459/comments","events_url":"https://api.github.com/repos/scikit-learn/scikit-learn/issues/4459/events","html_url":"https://github.com/scikit-learn/scikit-learn/issues/4459","id":64982386,"number":4459,"title":"sklearn random forest not parallelizing","user":{"login":"yang","id":7129,"avatar_url":"https://avatars.githubusercontent.com/u/7129?v=3","gravatar_id":"","url":"https://api.github.com/users/yang","html_url":"https://github.com/yang","followers_url":"https://api.github.com/users/yang/followers","following_url":"https://api.github.com/users/yang/following{/other_user}","gists_url":"https://api.github.com/users/yang/gists{/gist_id}","starred_url":"https://api.github.com/users/yang/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/yang/subscriptions","organizations_url":"https://api.github.com/users/yang/orgs","repos_url":"https://api.github.com/users/yang/repos","events_url":"https://api.github.com/users/yang/events{/privacy}","received_events_url":"https://api.github.com/users/yang/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-03-28T20:08:32Z","updated_at":"2015-03-28T20:08:32Z","closed_at":null,"body":"I'm using sklearn 0.16 on Ubuntu 12.04 and running:\r\n\r\n    from sklearn.ensemble import RandomForestClassifier\r\n    import numpy as np\r\n    X=np.random.rand(5000,500)\r\n    y=(np.random.rand(5000).round())\r\n    RandomForestClassifier(n_jobs=10,n_estimators=1000).fit(X,y)\r\n\r\nHowever it's not using up my cores, and takes the same time as n_jobs=1.  Any ideas on how to debug what's going on here?"}}