48 lines
662 B
C
48 lines
662 B
C
|
/*
|
||
|
|
* (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
|
||
|
|
* See the copyright notice in the ACK home directory, in the file "Copyright".
|
||
|
|
*
|
||
|
|
* Author: Ceriel J.H. Jacobs
|
||
|
|
*/
|
||
|
|
/* $Header$ */
|
||
|
|
|
||
|
|
#include <errno.h>
|
||
|
|
#include <math.h>
|
||
|
|
#include "localmath.h"
|
||
|
|
|
||
|
|
|
||
|
|
static double
|
||
|
|
asin_acos(double x, int cosfl)
|
||
|
|
{
|
||
|
|
int negative = x < 0;
|
||
|
|
|
||
|
|
if (negative) {
|
||
|
|
x = -x;
|
||
|
|
}
|
||
|
|
if (x > 1) {
|
||
|
|
errno = EDOM;
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
if (x == 1) {
|
||
|
|
x = M_PI_2;
|
||
|
|
}
|
||
|
|
else x = atan(x/sqrt(1-x*x));
|
||
|
|
if (negative) x = -x;
|
||
|
|
if (cosfl) {
|
||
|
|
return M_PI_2 - x;
|
||
|
|
}
|
||
|
|
return x;
|
||
|
|
}
|
||
|
|
|
||
|
|
double
|
||
|
|
asin(double x)
|
||
|
|
{
|
||
|
|
return asin_acos(x, 0);
|
||
|
|
}
|
||
|
|
|
||
|
|
double
|
||
|
|
acos(double x)
|
||
|
|
{
|
||
|
|
return asin_acos(x, 1);
|
||
|
|
}
|