Commit | Line | Data |
---|---|---|
547779a8 WH |
1 | #include "f2c.h" |
2 | ||
3 | #ifdef KR_headers | |
4 | extern double sqrt(), f__cabs(); | |
5 | ||
6 | VOID c_sqrt(r, z) complex *r, *z; | |
7 | #else | |
8 | #undef abs | |
9 | #include "math.h" | |
10 | extern double f__cabs(double, double); | |
11 | ||
12 | void c_sqrt(complex *r, complex *z) | |
13 | #endif | |
14 | { | |
15 | double mag, t; | |
16 | ||
17 | if( (mag = f__cabs(z->r, z->i)) == 0.) | |
18 | r->r = r->i = 0.; | |
19 | else if(z->r > 0) | |
20 | { | |
21 | r->r = t = sqrt(0.5 * (mag + z->r) ); | |
22 | t = z->i / t; | |
23 | r->i = 0.5 * t; | |
24 | } | |
25 | else | |
26 | { | |
27 | t = sqrt(0.5 * (mag - z->r) ); | |
28 | if(z->i < 0) | |
29 | t = -t; | |
30 | r->i = t; | |
31 | t = z->i / t; | |
32 | r->r = 0.5 * t; | |
33 | } | |
34 | } |