{"action":"opened","issue":{"url":"https://api.github.com/repos/mantidproject/mantid/issues/15749","repository_url":"https://api.github.com/repos/mantidproject/mantid","labels_url":"https://api.github.com/repos/mantidproject/mantid/issues/15749/labels{/name}","comments_url":"https://api.github.com/repos/mantidproject/mantid/issues/15749/comments","events_url":"https://api.github.com/repos/mantidproject/mantid/issues/15749/events","html_url":"https://github.com/mantidproject/mantid/issues/15749","id":143282362,"number":15749,"title":"GroupDetectors \"Grouping Pattern\" property does not work properly","user":{"login":"MattKing06","id":13132124,"avatar_url":"https://avatars.githubusercontent.com/u/13132124?v=3","gravatar_id":"","url":"https://api.github.com/users/MattKing06","html_url":"https://github.com/MattKing06","followers_url":"https://api.github.com/users/MattKing06/followers","following_url":"https://api.github.com/users/MattKing06/following{/other_user}","gists_url":"https://api.github.com/users/MattKing06/gists{/gist_id}","starred_url":"https://api.github.com/users/MattKing06/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/MattKing06/subscriptions","organizations_url":"https://api.github.com/users/MattKing06/orgs","repos_url":"https://api.github.com/users/MattKing06/repos","events_url":"https://api.github.com/users/MattKing06/events{/privacy}","received_events_url":"https://api.github.com/users/MattKing06/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/mantidproject/mantid/labels/Component:%20Framework","name":"Component: Framework","color":"009800"},{"url":"https://api.github.com/repos/mantidproject/mantid/labels/Misc:%20Bugfix","name":"Misc: Bugfix","color":"d4c5f9"}],"state":"open","locked":false,"assignee":null,"milestone":{"url":"https://api.github.com/repos/mantidproject/mantid/milestones/5","html_url":"https://github.com/mantidproject/mantid/milestones/Release%203.7","labels_url":"https://api.github.com/repos/mantidproject/mantid/milestones/5/labels","id":1106939,"number":5,"title":"Release 3.7","description":"","creator":{"login":"peterfpeterson","id":404003,"avatar_url":"https://avatars.githubusercontent.com/u/404003?v=3","gravatar_id":"","url":"https://api.github.com/users/peterfpeterson","html_url":"https://github.com/peterfpeterson","followers_url":"https://api.github.com/users/peterfpeterson/followers","following_url":"https://api.github.com/users/peterfpeterson/following{/other_user}","gists_url":"https://api.github.com/users/peterfpeterson/gists{/gist_id}","starred_url":"https://api.github.com/users/peterfpeterson/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/peterfpeterson/subscriptions","organizations_url":"https://api.github.com/users/peterfpeterson/orgs","repos_url":"https://api.github.com/users/peterfpeterson/repos","events_url":"https://api.github.com/users/peterfpeterson/events{/privacy}","received_events_url":"https://api.github.com/users/peterfpeterson/received_events","type":"User","site_admin":false},"open_issues":565,"closed_issues":432,"state":"open","created_at":"2015-05-12T15:38:13Z","updated_at":"2016-03-24T15:45:34Z","due_on":"2016-06-05T23:00:00Z","closed_at":null},"comments":0,"created_at":"2016-03-24T15:45:34Z","updated_at":"2016-03-24T15:45:34Z","closed_at":null,"body":"### Expected behavior\r\n- Group spectra with the workspace indices corresponding to Grouping Pattern i.e\r\n`GroupingPattern = \"1,2\"` should return a workspace containing the spectra at the second and third position in the workspace. \r\n- If we have a workspace that contains `sp-1, sp-3` only and `GroupingPattern = \"0,1\"` then we should get the same workspace back as an Output.\r\n### Actual behavior\r\n- If we have a workspace that contains `sp-1, sp-3` only and `GroupingPattern = \"0,1\"` then the algorithm fails to run and a warning is given stating \"Spectra number 2 does not exist in workspace\"\r\n\r\n### Steps to reproduce the behavior\r\n- Load any dataset that has 3 or more spectra using LoadNexus\r\n- In the LoadNexus dialog specify a spectrum list that contains a gap i.e \"1,3\" or \"3,7\" etc.\r\n- Bring up the algorithm dialog for `GroupDetectors` with the workspace from LoadNexus as the Input Workspace\r\n- In the \"Grouping Pattern\" Property enter the same value you did for LoadNexus (\"1,3\" for example)\r\n- See that the algorithm produces an error complaining about not be able to find the spectra between the two numbers you provided.\r\n### Platforms affected\r\n- All"}}