mirror of
git://gcc.gnu.org/git/gcc.git
synced 2024-12-23 19:10:02 +08:00
30 lines
514 B
C
30 lines
514 B
C
#include "f2c.h"
|
|
|
|
#ifdef KR_headers
|
|
double sqrt(), f__cabs();
|
|
VOID z_sqrt(r, z) doublecomplex *r, *z;
|
|
#else
|
|
#undef abs
|
|
#include "math.h"
|
|
extern double f__cabs(double, double);
|
|
void z_sqrt(doublecomplex *r, doublecomplex *z)
|
|
#endif
|
|
{
|
|
double mag, zi = z->i, zr = z->r;
|
|
|
|
if( (mag = f__cabs(zr, zi)) == 0.)
|
|
r->r = r->i = 0.;
|
|
else if(zr > 0)
|
|
{
|
|
r->r = sqrt(0.5 * (mag + zr) );
|
|
r->i = zi / r->r / 2;
|
|
}
|
|
else
|
|
{
|
|
r->i = sqrt(0.5 * (mag - zr) );
|
|
if(zi < 0)
|
|
r->i = - r->i;
|
|
r->r = zi / r->i / 2;
|
|
}
|
|
}
|