extend cmath (some of the functions are dummy)

[libm] / src / cmath / cacos.c

diff --git a/src/cmath/cacos.c b/src/cmath/cacos.c
index b8a2d71..3aca051 100644 (file)
--- a/src/cmath/cacos.c
+++ b/src/cmath/cacos.c
@@ -1,52 +1,11 @@
-/* origin: OpenBSD /usr/src/lib/libm/src/s_cacos.c */
-/*
- * Copyright (c) 2008 Stephen L. Moshier <steve@moshier.net>
- *
- * Permission to use, copy, modify, and distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- */
-/*
- *      Complex circular arc cosine
- *
- *
- * SYNOPSIS:
- *
- * double complex cacos();
- * double complex z, w;
- *
- * w = cacos (z);
- *
- *
- * DESCRIPTION:
- *
- *
- * w = arccos z  =  PI/2 - arcsin z.
- *
- *
- * ACCURACY:
- *
- *                      Relative error:
- * arithmetic   domain     # trials      peak         rms
- *    DEC       -10,+10      5200      1.6e-15      2.8e-16
- *    IEEE      -10,+10     30000      1.8e-14      2.2e-15
- */
-
 #include "libm.h"
 
+// FIXME: Hull et al. "Implementing the complex arcsine and arccosine functions using exception handling" 1997
+
+/* acos(z) = pi/2 - asin(z) */
+
 double complex cacos(double complex z)
 {
-       double complex w;
-
-       w = casin(z);
-       w = (M_PI_2 - creal(w)) - cimag(w) * I;
-       return w;
+       z = casin(z);
+       return cpack(M_PI_2 - creal(z), -cimag(z));
 }