Mercurial > octave-libtiff
changeset 29167:9193e7c990ea
sind.m, sinpi.m, cospi.m: Wrap to interval closer to zero for higher accuracy.
* scripts/elfun/sind.m, scripts/elfun/sinpi.m, scripts/elfun/cospi.m: Wrap
input to interval [-pi,pi) for higher numeric accuracy.
| author | Markus Mützel <markus.muetzel@gmx.de> |
|---|---|
| date | Wed, 09 Dec 2020 20:04:59 +0100 |
| parents | fbf6d132dec7 |
| children | 8a2449d40f3c |
| files | scripts/elfun/cospi.m scripts/elfun/sind.m scripts/elfun/sinpi.m |
| diffstat | 3 files changed, 9 insertions(+), 9 deletions(-) [+] |
line wrap: on
line diff
--- a/scripts/elfun/cospi.m Wed Dec 09 19:25:01 2020 +0100 +++ b/scripts/elfun/cospi.m Wed Dec 09 20:04:59 2020 +0100 @@ -58,11 +58,11 @@ endif ## Advance phase by pi/2 so that algorithm from sinpi can be used. - ## Unwrap integer multiples so that new domain is [0, 2). - x = mod (x + 0.5, 2); + ## Wrap integer multiples so that new domain is [-1, 1). + x = mod (x - 0.5, 2) - 1; ## Integer multiples of pi must be exactly zero. - x(x == 1) = 0; + x(x == -1) = 0; y = sin (x * pi);
--- a/scripts/elfun/sind.m Wed Dec 09 19:25:01 2020 +0100 +++ b/scripts/elfun/sind.m Wed Dec 09 20:04:59 2020 +0100 @@ -38,11 +38,11 @@ print_usage (); endif - ## Unwrap multiples so that new domain is [0, 360) - x = mod (x, 360); + ## Wrap multiples so that new domain is [-180, 180) + x = mod (x-180, 360) - 180; ## Integer multiples of pi must be exactly zero - x(x == 180) = 0; + x(x == -180) = 0; y = sin (x / 180 * pi);
--- a/scripts/elfun/sinpi.m Wed Dec 09 19:25:01 2020 +0100 +++ b/scripts/elfun/sinpi.m Wed Dec 09 20:04:59 2020 +0100 @@ -57,11 +57,11 @@ print_usage (); endif - ## Unwrap integer multiples so that new domain is [0, 2) - x = mod (x, 2); + ## Wrap integer multiples so that new domain is [-1, 1) + x = mod (x-1, 2) - 1; ## Integer multiples of pi must be exactly zero - x(x == 1) = 0; + x(x == -1) = 0; y = sin (x * pi);