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