1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
|
#include "v3p_f2c.h"
#ifdef KR_headers
extern double sqrt(), f__cabs();
VOID c_sqrt(r, z) complex *r, *z;
#else
#undef abs
#include "math.h"
#ifdef __cplusplus
extern "C" {
#endif
extern double f__cabs(double, double);
#undef complex
#define complex v3p_netlib_complex
void c_sqrt(complex *r, complex *z)
#endif
{
double mag, t;
double zi = z->i, zr = z->r;
if( (mag = f__cabs(zr, zi)) == 0.)
r->r = r->i = 0.0f;
else if(zr > 0)
{
r->r = (real)(t = sqrt(0.5 * (mag + zr) ));
t = zi / t;
r->i = (real)( 0.5 * t);
}
else
{
t = sqrt(0.5 * (mag - zr) );
if(zi < 0)
t = -t;
r->i = (real)t;
t = zi / t;
r->r = (real)(0.5 * t);
}
}
#ifdef __cplusplus
}
#endif
|
