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authordwmalone <dwmalone@FreeBSD.org>2001-11-05 10:10:33 +0000
committerdwmalone <dwmalone@FreeBSD.org>2001-11-05 10:10:33 +0000
commitf8a5b8b8e0f1c87d1176a4c5c2603581148fdad2 (patch)
treed8887009d765d5cb91b1cc6bc5e93830b88967c7 /lib
parent021d2ea214a30ad372a5b46656c8b0aea2a3ad0c (diff)
downloadFreeBSD-src-f8a5b8b8e0f1c87d1176a4c5c2603581148fdad2.zip
FreeBSD-src-f8a5b8b8e0f1c87d1176a4c5c2603581148fdad2.tar.gz
gamma(x) actually returns \log(|\Gamma(x)|), so correct the man
page and add an historical note explaining this. This patch is based on Stephen's. We still need someone to implement tgamma. PR: 28972, 31764 Submitted by: Stephen Montgomery-Smith <stephen@math.missouri.edu>
Diffstat (limited to 'lib')
-rw-r--r--lib/msun/man/lgamma.344
1 files changed, 28 insertions, 16 deletions
diff --git a/lib/msun/man/lgamma.3 b/lib/msun/man/lgamma.3
index ec094cc..279eb3e 100644
--- a/lib/msun/man/lgamma.3
+++ b/lib/msun/man/lgamma.3
@@ -78,7 +78,7 @@ returns the sign of \(*G(x).
.Fn gamma x
and
.Fn gammaf x
-return \(*G(x), with no effect on
+return ln\||\(*G(x)|, with no effect on
.Fa signgam .
.Sh IDIOSYNCRASIES
Do not use the expression
@@ -94,16 +94,16 @@ Only after
or
.Fn lgammaf
has returned can signgam be correct.
-.Pp
-For arguments in its range,
-.Fn gamma
-and
-.Fn gammaf
-is preferred, as for positive arguments
-it is accurate to within one unit in the last place.
-Exponentiation of
-.Fn lgamma
-will lose up to 10 significant bits.
+.\.Pp
+.\For arguments in its range,
+.\.Fn gamma
+.\and
+.\.Fn gammaf
+.\is preferred, as for positive arguments
+.\it is accurate to within one unit in the last place.
+.\Exponentiation of
+.\.Fn lgamma
+.\will lose up to 10 significant bits.
.Sh RETURN VALUES
.Fn gamma ,
.Fn gammaf ,
@@ -133,9 +133,21 @@ function appeared in
The
.Fn gamma
function appeared in
-.Bx 4.4 .
-The name
+.Bx 4.4
+as a function which computed \(*G(x).
+In many older libraries the function
.Fn gamma
-was originally dedicated to the
-.Fn lgamma
-function, so some old code may no longer be compatible.
+calculated the same value as
+.Fn lgamma .
+Now
+.Fn gamma
+computes ln\||\(*G(x)|,
+but it uses a different algorithm,
+and it does not set
+.Fa signgam .
+The
+.St -isoC-99
+standard specifies a function
+.Fn tgamma
+for computing \(*G(x).
+This function is currently unimplimented in this library.
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