{"action":"created","issue":{"url":"https://api.github.com/repos/apache/spark/issues/13621","repository_url":"https://api.github.com/repos/apache/spark","labels_url":"https://api.github.com/repos/apache/spark/issues/13621/labels{/name}","comments_url":"https://api.github.com/repos/apache/spark/issues/13621/comments","events_url":"https://api.github.com/repos/apache/spark/issues/13621/events","html_url":"https://github.com/apache/spark/pull/13621","id":159802070,"number":13621,"title":"[SPARK-2623] [ML] Implement stacked autoencoder","user":{"login":"avulanov","id":939524,"avatar_url":"https://avatars.githubusercontent.com/u/939524?v=3","gravatar_id":"","url":"https://api.github.com/users/avulanov","html_url":"https://github.com/avulanov","followers_url":"https://api.github.com/users/avulanov/followers","following_url":"https://api.github.com/users/avulanov/following{/other_user}","gists_url":"https://api.github.com/users/avulanov/gists{/gist_id}","starred_url":"https://api.github.com/users/avulanov/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/avulanov/subscriptions","organizations_url":"https://api.github.com/users/avulanov/orgs","repos_url":"https://api.github.com/users/avulanov/repos","events_url":"https://api.github.com/users/avulanov/events{/privacy}","received_events_url":"https://api.github.com/users/avulanov/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":7,"created_at":"2016-06-12T01:31:49Z","updated_at":"2016-08-08T14:32:54Z","closed_at":null,"pull_request":{"url":"https://api.github.com/repos/apache/spark/pulls/13621","html_url":"https://github.com/apache/spark/pull/13621","diff_url":"https://github.com/apache/spark/pull/13621.diff","patch_url":"https://github.com/apache/spark/pull/13621.patch"},"body":"## What changes were proposed in this pull request?\r\nImplement stacked autoencoder\r\n- Base on ml.ann Layer and LossFunction\r\n- Implement two loss functions `EmptyLayerWithSquaredError` and `SigmoidLayerWithSquaredError` to handle inputs (-inf, +inf) and [0, 1]\r\n- Implement greedy training\r\n- Provide encoder and decoder\r\n\r\n## How was this patch tested?\r\nProvide unit tests\r\n- Gradient correctness of the new LossFunctions\r\n- Correct reconstruction of the original data by encoding and decoding (based on Berkeley's CS182)\r\n- Successful pre-training of deep network with 6 hidden layers"},"comment":{"url":"https://api.github.com/repos/apache/spark/issues/comments/238256274","html_url":"https://github.com/apache/spark/pull/13621#issuecomment-238256274","issue_url":"https://api.github.com/repos/apache/spark/issues/13621","id":238256274,"user":{"login":"MLnick","id":1036807,"avatar_url":"https://avatars.githubusercontent.com/u/1036807?v=3","gravatar_id":"","url":"https://api.github.com/users/MLnick","html_url":"https://github.com/MLnick","followers_url":"https://api.github.com/users/MLnick/followers","following_url":"https://api.github.com/users/MLnick/following{/other_user}","gists_url":"https://api.github.com/users/MLnick/gists{/gist_id}","starred_url":"https://api.github.com/users/MLnick/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/MLnick/subscriptions","organizations_url":"https://api.github.com/users/MLnick/orgs","repos_url":"https://api.github.com/users/MLnick/repos","events_url":"https://api.github.com/users/MLnick/events{/privacy}","received_events_url":"https://api.github.com/users/MLnick/received_events","type":"User","site_admin":false},"created_at":"2016-08-08T14:32:54Z","updated_at":"2016-08-08T14:32:54Z","body":"cc @JeremyNixon also"}}
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