mirror of
git://gcc.gnu.org/git/gcc.git
synced 2024-12-24 01:09:24 +08:00
39 lines
568 B
C
39 lines
568 B
C
|
#include "f2c.h"
|
||
|
|
|
||
|
|
#ifdef KR_headers
|
||
|
|
extern double sqrt(), f__cabs();
|
||
|
|
|
||
|
|
VOID c_sqrt(resx, z) complex *resx, *z;
|
||
|
|
#else
|
||
|
|
#undef abs
|
||
|
|
#include <math.h>
|
||
|
|
extern double f__cabs(double, double);
|
||
|
|
|
||
|
|
void c_sqrt(complex *resx, complex *z)
|
||
|
|
#endif
|
||
|
|
{
|
||
|
|
double mag, t;
|
||
|
|
complex res;
|
||
|
|
|
||
|
|
if( (mag = f__cabs(z->r, z->i)) == 0.)
|
||
|
|
res.r = res.i = 0.;
|
||
|
|
else if(z->r > 0)
|
||
|
|
{
|
||
|
|
res.r = t = sqrt(0.5 * (mag + z->r) );
|
||
|
|
t = z->i / t;
|
||
|
|
res.i = 0.5 * t;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
t = sqrt(0.5 * (mag - z->r) );
|
||
|
|
if(z->i < 0)
|
||
|
|
t = -t;
|
||
|
|
res.i = t;
|
||
|
|
t = z->i / t;
|
||
|
|
res.r = 0.5 * t;
|
||
|
|
}
|
||
|
|
|
||
|
|
resx->r = res.r;
|
||
|
|
resx->i = res.i;
|
||
|
|
}
|