{"action":"created","issue":{"url":"https://api.github.com/repos/tuan3w/cs231n/issues/1","labels_url":"https://api.github.com/repos/tuan3w/cs231n/issues/1/labels{/name}","comments_url":"https://api.github.com/repos/tuan3w/cs231n/issues/1/comments","events_url":"https://api.github.com/repos/tuan3w/cs231n/issues/1/events","html_url":"https://github.com/tuan3w/cs231n/issues/1","id":108674335,"number":1,"title":"Cross entropy loss gradient","user":{"login":"victorhcm","id":3802222,"avatar_url":"https://avatars.githubusercontent.com/u/3802222?v=3","gravatar_id":"","url":"https://api.github.com/users/victorhcm","html_url":"https://github.com/victorhcm","followers_url":"https://api.github.com/users/victorhcm/followers","following_url":"https://api.github.com/users/victorhcm/following{/other_user}","gists_url":"https://api.github.com/users/victorhcm/gists{/gist_id}","starred_url":"https://api.github.com/users/victorhcm/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/victorhcm/subscriptions","organizations_url":"https://api.github.com/users/victorhcm/orgs","repos_url":"https://api.github.com/users/victorhcm/repos","events_url":"https://api.github.com/users/victorhcm/events{/privacy}","received_events_url":"https://api.github.com/users/victorhcm/received_events","type":"User","site_admin":false},"labels":[],"state":"closed","locked":false,"assignee":null,"milestone":null,"comments":2,"created_at":"2015-09-28T14:52:54Z","updated_at":"2015-09-28T17:04:08Z","closed_at":"2015-09-28T17:04:07Z","body":"Hi @tuan3w, \r\n\r\nI have recently started doing the course and I'm currently trying to compute the gradient of the cross entropy loss for the Softmax function. I was able to find the gradient w.r.t. [$f_{y_i}$](https://github.com/tuan3w/cs231n/blob/master/assignment1/cs231n/classifiers/softmax.py#L39), but I'm having trouble to compute the gradient with regarding [$f_{j}$](https://github.com/tuan3w/cs231n/blob/master/assignment1/cs231n/classifiers/softmax.py#L37). In your gradient, you have found $\\frac{e^{f_j}}{\\sum_j{e^{f_j}}} * x_i$, while I'm finding only $x_i$.\r\n\r\nHow have you done it? :)\r\n\r\nThanks!"},"comment":{"url":"https://api.github.com/repos/tuan3w/cs231n/issues/comments/143805468","html_url":"https://github.com/tuan3w/cs231n/issues/1#issuecomment-143805468","issue_url":"https://api.github.com/repos/tuan3w/cs231n/issues/1","id":143805468,"user":{"login":"victorhcm","id":3802222,"avatar_url":"https://avatars.githubusercontent.com/u/3802222?v=3","gravatar_id":"","url":"https://api.github.com/users/victorhcm","html_url":"https://github.com/victorhcm","followers_url":"https://api.github.com/users/victorhcm/followers","following_url":"https://api.github.com/users/victorhcm/following{/other_user}","gists_url":"https://api.github.com/users/victorhcm/gists{/gist_id}","starred_url":"https://api.github.com/users/victorhcm/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/victorhcm/subscriptions","organizations_url":"https://api.github.com/users/victorhcm/orgs","repos_url":"https://api.github.com/users/victorhcm/repos","events_url":"https://api.github.com/users/victorhcm/events{/privacy}","received_events_url":"https://api.github.com/users/victorhcm/received_events","type":"User","site_admin":false},"created_at":"2015-09-28T17:04:07Z","updated_at":"2015-09-28T17:04:07Z","body":"Thank you, @tuan3w! I didn't see it there :D "}}