{"action":"created","issue":{"url":"https://api.github.com/repos/astropy/astropy/issues/4177","labels_url":"https://api.github.com/repos/astropy/astropy/issues/4177/labels{/name}","comments_url":"https://api.github.com/repos/astropy/astropy/issues/4177/comments","events_url":"https://api.github.com/repos/astropy/astropy/issues/4177/events","html_url":"https://github.com/astropy/astropy/pull/4177","id":107494444,"number":4177,"title":"NDArithmetic: Use zero if no uncertainty is set in uncertainty propagation","user":{"login":"MSeifert04","id":14200878,"avatar_url":"https://avatars.githubusercontent.com/u/14200878?v=3","gravatar_id":"","url":"https://api.github.com/users/MSeifert04","html_url":"https://github.com/MSeifert04","followers_url":"https://api.github.com/users/MSeifert04/followers","following_url":"https://api.github.com/users/MSeifert04/following{/other_user}","gists_url":"https://api.github.com/users/MSeifert04/gists{/gist_id}","starred_url":"https://api.github.com/users/MSeifert04/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/MSeifert04/subscriptions","organizations_url":"https://api.github.com/users/MSeifert04/orgs","repos_url":"https://api.github.com/users/MSeifert04/repos","events_url":"https://api.github.com/users/MSeifert04/events{/privacy}","received_events_url":"https://api.github.com/users/MSeifert04/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":2,"created_at":"2015-09-21T11:46:40Z","updated_at":"2015-09-21T22:53:05Z","closed_at":null,"pull_request":{"url":"https://api.github.com/repos/astropy/astropy/pulls/4177","html_url":"https://github.com/astropy/astropy/pull/4177","diff_url":"https://github.com/astropy/astropy/pull/4177.diff","patch_url":"https://github.com/astropy/astropy/pull/4177.patch"},"body":"But this produces additional computation time for addition/subtraction. But for multiplication and division the resulting uncertainty is now correct.\r\n\r\nCloses #4152 "},"comment":{"url":"https://api.github.com/repos/astropy/astropy/issues/comments/142131339","html_url":"https://github.com/astropy/astropy/pull/4177#issuecomment-142131339","issue_url":"https://api.github.com/repos/astropy/astropy/issues/4177","id":142131339,"user":{"login":"MSeifert04","id":14200878,"avatar_url":"https://avatars.githubusercontent.com/u/14200878?v=3","gravatar_id":"","url":"https://api.github.com/users/MSeifert04","html_url":"https://github.com/MSeifert04","followers_url":"https://api.github.com/users/MSeifert04/followers","following_url":"https://api.github.com/users/MSeifert04/following{/other_user}","gists_url":"https://api.github.com/users/MSeifert04/gists{/gist_id}","starred_url":"https://api.github.com/users/MSeifert04/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/MSeifert04/subscriptions","organizations_url":"https://api.github.com/users/MSeifert04/orgs","repos_url":"https://api.github.com/users/MSeifert04/repos","events_url":"https://api.github.com/users/MSeifert04/events{/privacy}","received_events_url":"https://api.github.com/users/MSeifert04/received_events","type":"User","site_admin":false},"created_at":"2015-09-21T22:53:05Z","updated_at":"2015-09-21T22:53:05Z","body":"I had time to think about the issue and wanted another approach that works well even if not both ``NDData`` have an uncertainty but without the additional computations. I don't know how to link another branch I created but does https://github.com/MSeifert04/astropy/pull/1 work for anyone?\r\n\r\nbtw: Is there any bug in the travis tests? Seems like the problems arise from another source not any changes I tried to make with the PR"}}