From: Akila Welihinda <akilawelihinda@ucla.edu>
To: libc-alpha@sourceware.org
Cc: Akila Welihinda <akilawelihinda@ucla.edu>
Subject: [PATCH] sysdeps: Update Taylor Series formula in comment
Date: Sat, 11 Dec 2021 14:50:03 -0800 [thread overview]
Message-ID: <20211211225003.6772-1-akilawelihinda@ucla.edu> (raw)
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 --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. */
--
2.30.1 (Apple Git-130)
next reply other threads:[~2021-12-11 22:50 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-11 22:50 Akila Welihinda [this message]
-- strict thread matches above, loose matches on Subject: below --
2021-12-11 18:02 Akila Welihinda
2021-12-12 6:34 ` Paul Zimmermann
2021-12-12 16:50 ` Akila Welihinda
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