{"action":"created","issue":{"url":"https://api.github.com/repos/vlfeat/matconvnet/issues/292","labels_url":"https://api.github.com/repos/vlfeat/matconvnet/issues/292/labels{/name}","comments_url":"https://api.github.com/repos/vlfeat/matconvnet/issues/292/comments","events_url":"https://api.github.com/repos/vlfeat/matconvnet/issues/292/events","html_url":"https://github.com/vlfeat/matconvnet/issues/292","id":112511634,"number":292,"title":"Aren't Class labels used during backpropagation ? ","user":{"login":"eunjoa","id":14211756,"avatar_url":"https://avatars.githubusercontent.com/u/14211756?v=3","gravatar_id":"","url":"https://api.github.com/users/eunjoa","html_url":"https://github.com/eunjoa","followers_url":"https://api.github.com/users/eunjoa/followers","following_url":"https://api.github.com/users/eunjoa/following{/other_user}","gists_url":"https://api.github.com/users/eunjoa/gists{/gist_id}","starred_url":"https://api.github.com/users/eunjoa/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/eunjoa/subscriptions","organizations_url":"https://api.github.com/users/eunjoa/orgs","repos_url":"https://api.github.com/users/eunjoa/repos","events_url":"https://api.github.com/users/eunjoa/events{/privacy}","received_events_url":"https://api.github.com/users/eunjoa/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":7,"created_at":"2015-10-21T04:37:14Z","updated_at":"2015-10-22T11:21:40Z","closed_at":null,"body":"Here is my problem, i am fine tuning the CIFAR model for my new dataset of only two classes, the labels are just 1 or 2. i want the output of my network to be probabilities for the two classes, i used softmax as a last layer so my output is of the from [1 1 2],   Now at backpropagation \r\n\r\nE = exp(bsxfun(@minus, X, max(X,[],3))) ;\r\nL = sum(E,3) ;\r\nY = bsxfun(@rdivide, E, L) ;\r\n\r\nif nargin <= 1, return ; end\r\nY = Y .* bsxfun(@minus, dzdY,  sum(dzdY .* Y, 3)) ;\r\nwhere : dzdY = single(1) \r\n\r\nare the class labels not used in the backprop at the last layer ?? \r\nThis is confusing me, i would appreciate any clarification. "},"comment":{"url":"https://api.github.com/repos/vlfeat/matconvnet/issues/comments/150184718","html_url":"https://github.com/vlfeat/matconvnet/issues/292#issuecomment-150184718","issue_url":"https://api.github.com/repos/vlfeat/matconvnet/issues/292","id":150184718,"user":{"login":"eunjoa","id":14211756,"avatar_url":"https://avatars.githubusercontent.com/u/14211756?v=3","gravatar_id":"","url":"https://api.github.com/users/eunjoa","html_url":"https://github.com/eunjoa","followers_url":"https://api.github.com/users/eunjoa/followers","following_url":"https://api.github.com/users/eunjoa/following{/other_user}","gists_url":"https://api.github.com/users/eunjoa/gists{/gist_id}","starred_url":"https://api.github.com/users/eunjoa/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/eunjoa/subscriptions","organizations_url":"https://api.github.com/users/eunjoa/orgs","repos_url":"https://api.github.com/users/eunjoa/repos","events_url":"https://api.github.com/users/eunjoa/events{/privacy}","received_events_url":"https://api.github.com/users/eunjoa/received_events","type":"User","site_admin":false},"created_at":"2015-10-22T11:21:40Z","updated_at":"2015-10-22T11:21:40Z","body":"okay thank you i will try to fix that."}}