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authordrochner <drochner@NetBSD.org>2009-08-03 19:41:32 +0000
committerdrochner <drochner@NetBSD.org>2009-08-03 19:41:32 +0000
commitaa89e1b4263a973bd331d18b5fcd9b063a99425d (patch)
treeebc35638e117ceead2cedff5d4d49eacd7af273c /lib/libm/complex
parent143caecc0df89ab82179d45f136343a06eab5d0d (diff)
As noticed by Stathis Kamperis, the original implementation does not
always return the correct principal value (with real>=0). (eg cacosh(ccos(1.0I)) was -1) Replace by a more ground-up one which should do better.
Diffstat (limited to 'lib/libm/complex')
-rw-r--r--lib/libm/complex/cacosh.c6
-rw-r--r--lib/libm/complex/cacoshf.c6
2 files changed, 10 insertions, 2 deletions
diff --git a/lib/libm/complex/cacosh.c b/lib/libm/complex/cacosh.c
index 96373ae7d38..fcfb365bea3 100644
--- a/lib/libm/complex/cacosh.c
+++ b/lib/libm/complex/cacosh.c
@@ -1,4 +1,4 @@
-/* $NetBSD: cacosh.c,v 1.1 2007/08/20 16:01:30 drochner Exp $ */
+/* $NetBSD: cacosh.c,v 1.2 2009/08/03 19:41:32 drochner Exp $ */
/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
@@ -36,6 +36,10 @@ cacosh(double complex z)
{
double complex w;
+#if 0 /* does not give the principal value */
w = I * cacos(z);
+#else
+ w = clog(z + csqrt(z + 1) * csqrt(z - 1));
+#endif
return w;
}
diff --git a/lib/libm/complex/cacoshf.c b/lib/libm/complex/cacoshf.c
index ec60445acad..76295d59720 100644
--- a/lib/libm/complex/cacoshf.c
+++ b/lib/libm/complex/cacoshf.c
@@ -1,4 +1,4 @@
-/* $NetBSD: cacoshf.c,v 1.1 2007/08/20 16:01:31 drochner Exp $ */
+/* $NetBSD: cacoshf.c,v 1.2 2009/08/03 19:41:32 drochner Exp $ */
/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
@@ -36,6 +36,10 @@ cacoshf(float complex z)
{
float complex w;
+#if 0 /* does not give the principal value */
w = I * cacosf(z);
+#else
+ w = clogf(z + csqrtf(z + 1) * csqrtf(z - 1));
+#endif
return w;
}