Mercurial > octave
changeset 29164:b7a4460333c9
cosd.m: Use new improved sind.m for greater accuracy.
* cosd.m: Advance phase by 90 degrees and then call sind() to take advantage of
improved algorithm. Update BIST tests.
| author | Rik <rik@octave.org> |
|---|---|
| date | Tue, 08 Dec 2020 20:09:19 -0800 |
| parents | 8f67ad8b3103 |
| children | 617d3aa713a4 |
| files | scripts/elfun/cosd.m |
| diffstat | 1 files changed, 5 insertions(+), 7 deletions(-) [+] |
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--- a/scripts/elfun/cosd.m Tue Dec 08 13:25:03 2020 -0800 +++ b/scripts/elfun/cosd.m Tue Dec 08 20:09:19 2020 -0800 @@ -37,16 +37,14 @@ print_usage (); endif - I = x / 180; - y = cos (I .* pi); - I += 0.5; - y(I == fix (I) & isfinite (I)) = 0; + ## Advance phase by 90 degrees to turn sin in to cos and use sind. + y = sind (x + 90); endfunction -%!assert (cosd (0:10:80), cos (pi*[0:10:80]/180), -10*eps) -%!assert (cosd ([0, 180, 360]) != 0) -%!assert (cosd ([90, 270]) == 0) +%!assert (cosd (10:20:360), cos ([10:20:360] * pi/180), 5*eps) +%!assert (cosd ([-270, -90, 90, 270]) == 0) +%!assert (cosd ([-360, -180, 0, 180, 360]), [1, -1, 1, -1, 1]) %!error <Invalid call> cosd ()