{"action":"created","issue":{"url":"https://api.github.com/repos/supercollider/supercollider/issues/1504","labels_url":"https://api.github.com/repos/supercollider/supercollider/issues/1504/labels{/name}","comments_url":"https://api.github.com/repos/supercollider/supercollider/issues/1504/comments","events_url":"https://api.github.com/repos/supercollider/supercollider/issues/1504/events","html_url":"https://github.com/supercollider/supercollider/pull/1504","id":82003219,"number":1504,"title":"Chebyshev polynomials: various fixes (issue #1500)","user":{"login":"totalgee","id":306082,"avatar_url":"https://avatars.githubusercontent.com/u/306082?v=3","gravatar_id":"","url":"https://api.github.com/users/totalgee","html_url":"https://github.com/totalgee","followers_url":"https://api.github.com/users/totalgee/followers","following_url":"https://api.github.com/users/totalgee/following{/other_user}","gists_url":"https://api.github.com/users/totalgee/gists{/gist_id}","starred_url":"https://api.github.com/users/totalgee/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/totalgee/subscriptions","organizations_url":"https://api.github.com/users/totalgee/orgs","repos_url":"https://api.github.com/users/totalgee/repos","events_url":"https://api.github.com/users/totalgee/events{/privacy}","received_events_url":"https://api.github.com/users/totalgee/received_events","type":"User","site_admin":false},"labels":[],"state":"closed","locked":false,"assignee":null,"milestone":null,"comments":6,"created_at":"2015-05-28T16:04:31Z","updated_at":"2015-05-31T17:03:21Z","closed_at":"2015-05-31T06:54:13Z","pull_request":{"url":"https://api.github.com/repos/supercollider/supercollider/pulls/1504","html_url":"https://github.com/supercollider/supercollider/pull/1504","diff_url":"https://github.com/supercollider/supercollider/pull/1504.diff","patch_url":"https://github.com/supercollider/supercollider/pull/1504.patch"},"body":"These are several things I found while looking at the issues raised in #1500.  Besides adding the ability to produce the \"raw\" Chebyshev polynomials (by passing `normalize: false`and a new option `zeroOffset: false` to Signal.chebyFill and Wavetable.chebyFill), I fixed two problems I found along the way:\r\n\r\n1. `Signal.chebyFill` was not taking amplitudes into account when offsetting for DC.  The fix was there, but it always added or subtracted 1 in the the relevant places.  Worst of all, for amplitudes of 0 it came across (whose poly degrees would otherwise need offsetting), it was always adding and subtracting 1!  This was probably not noticed, because with `normalize: true` (default) it shifted the whole thing to lie between -1 and 1.\r\n\r\n2. `Buffer.chebyMsg` (and `Buffer.cheby`) were not adding the DC offset in the proper direction!  The idea is to ensure that the middle value is at zero. Now fixed, this gives the same result as Signal.chebyFill (when `zeroOffset` is true -- the default case).\r\n\r\nI also added a bit of documentation for the old normalize argument and my new zeroOffset argument."},"comment":{"url":"https://api.github.com/repos/supercollider/supercollider/issues/comments/107223617","html_url":"https://github.com/supercollider/supercollider/pull/1504#issuecomment-107223617","issue_url":"https://api.github.com/repos/supercollider/supercollider/issues/1504","id":107223617,"user":{"login":"totalgee","id":306082,"avatar_url":"https://avatars.githubusercontent.com/u/306082?v=3","gravatar_id":"","url":"https://api.github.com/users/totalgee","html_url":"https://github.com/totalgee","followers_url":"https://api.github.com/users/totalgee/followers","following_url":"https://api.github.com/users/totalgee/following{/other_user}","gists_url":"https://api.github.com/users/totalgee/gists{/gist_id}","starred_url":"https://api.github.com/users/totalgee/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/totalgee/subscriptions","organizations_url":"https://api.github.com/users/totalgee/orgs","repos_url":"https://api.github.com/users/totalgee/repos","events_url":"https://api.github.com/users/totalgee/events{/privacy}","received_events_url":"https://api.github.com/users/totalgee/received_events","type":"User","site_admin":false},"created_at":"2015-05-31T17:03:21Z","updated_at":"2015-05-31T17:03:21Z","body":"Yes, several of us think it should (see mailing list). Haven't heard a\ndissenting opinion yet... Should I change it?\n"}}