{"action":"opened","issue":{"url":"https://api.github.com/repos/scipy/scipy/issues/4894","labels_url":"https://api.github.com/repos/scipy/scipy/issues/4894/labels{/name}","comments_url":"https://api.github.com/repos/scipy/scipy/issues/4894/comments","events_url":"https://api.github.com/repos/scipy/scipy/issues/4894/events","html_url":"https://github.com/scipy/scipy/issues/4894","id":78268883,"number":4894,"title":"scipy.special.hyp2f1 giving more incorrect results","user":{"login":"Vectornaut","id":12519587,"avatar_url":"https://avatars.githubusercontent.com/u/12519587?v=3","gravatar_id":"","url":"https://api.github.com/users/Vectornaut","html_url":"https://github.com/Vectornaut","followers_url":"https://api.github.com/users/Vectornaut/followers","following_url":"https://api.github.com/users/Vectornaut/following{/other_user}","gists_url":"https://api.github.com/users/Vectornaut/gists{/gist_id}","starred_url":"https://api.github.com/users/Vectornaut/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/Vectornaut/subscriptions","organizations_url":"https://api.github.com/users/Vectornaut/orgs","repos_url":"https://api.github.com/users/Vectornaut/repos","events_url":"https://api.github.com/users/Vectornaut/events{/privacy}","received_events_url":"https://api.github.com/users/Vectornaut/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-05-19T22:07:12Z","updated_at":"2015-05-19T22:07:12Z","closed_at":null,"body":"*Possibly related to #3479?*\r\n\r\nWhen *z* is near 0.95j, evaluating `hyp2f1(1/2., 2/3., 3/2., z)` gives results that are wrong by 60 or 70 orders of magnitude. The bad region has very sharp boundaries. For example, stepping up the imaginary axis with an increment of 0.01j,\r\n\r\n* I go from the correct value 0.93 + 0.16j to the incorrect value 4e62 + 4e62j in the step to 0.90j, and\r\n* I go from the incorrect value 4e73 - 2e72j back to the correct value 0.92 + 0.18j in the step from 1j.\r\n\r\nThe bad region extends away from the imaginary axis, at least out to real part 1/3.\r\n\r\nWorking example:\r\n\r\n```python\r\nfrom scipy.special import hyp2f1\r\n\r\nfor n in range(41):\r\n  z = 0.75j + n*0.01j\r\n  print 'f({}) = {}'.format(z, hyp2f1(1/2., 2/3., 3/2., z))\r\n```"}}