35 lines
505 B
C
35 lines
505 B
C
|
#include "f2c.h"
|
||
|
|
|
||
|
|
#ifdef KR_headers
|
||
|
|
extern double sqrt(), f__cabs();
|
||
|
|
|
||
|
|
VOID c_sqrt(r, z) complex *r, *z;
|
||
|
|
#else
|
||
|
|
#undef abs
|
||
|
|
#include "math.h"
|
||
|
|
extern double f__cabs(double, double);
|
||
|
|
|
||
|
|
void c_sqrt(complex *r, complex *z)
|
||
|
|
#endif
|
||
|
|
{
|
||
|
|
double mag, t;
|
||
|
|
|
||
|
|
if( (mag = f__cabs(z->r, z->i)) == 0.)
|
||
|
|
r->r = r->i = 0.;
|
||
|
|
else if(z->r > 0)
|
||
|
|
{
|
||
|
|
r->r = t = sqrt(0.5 * (mag + z->r) );
|
||
|
|
t = z->i / t;
|
||
|
|
r->i = 0.5 * t;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
t = sqrt(0.5 * (mag - z->r) );
|
||
|
|
if(z->i < 0)
|
||
|
|
t = -t;
|
||
|
|
r->i = t;
|
||
|
|
t = z->i / t;
|
||
|
|
r->r = 0.5 * t;
|
||
|
|
}
|
||
|
|
}
|