diff mbox series

sysdeps: Update Taylor Series formula in comment

Message ID 20211211225003.6772-1-akilawelihinda@ucla.edu
State Superseded
Headers
Series sysdeps: Update Taylor Series formula in comment |

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent
dj/TryBot-32bit success Build for i686

Commit Message

Akila Welihinda Dec. 11, 2021, 10:50 p.m. UTC 
  The macro TAYLOR_SIN adds the term `-0.5*da*a^2 + da` in hopes
of regaining some precision as a function of da. However the
comment says we add the term `-0.5*da*a^2 + 0.5*da` which is
different. This fix just updates the comment to reflect the
code.

Signed-off-by: Akila Welihinda <akilawelihinda@ucla.edu>
---
 sysdeps/ieee754/dbl-64/s_sin.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/sysdeps/ieee754/dbl-64/s_sin.c b/sysdeps/ieee754/dbl-64/s_sin.c
index 7d89e3dfc2..31e08e3a70 100644
--- a/sysdeps/ieee754/dbl-64/s_sin.c
+++ b/sysdeps/ieee754/dbl-64/s_sin.c
@@ -53,7 +53,7 @@ 
 /* The computed polynomial is a variation of the Taylor series expansion for
    sin(a):
 
-   a - a^3/3! + a^5/5! - a^7/7! + a^9/9! + (1 - a^2) * da / 2
+   a - a^3/3! + a^5/5! - a^7/7! + a^9/9! - da*a^2/2 + da
 
    The constants s1, s2, s3, etc. are pre-computed values of 1/3!, 1/5! and so
    on.  The result is returned to LHS.  */