xref: /csrg-svn/usr.bin/f77/libF77/pow_zz.c (revision 10517)
1*10517Sdlw /*
2*10517Sdlw  *	"@(#)pow_zz.c	1.1"
3*10517Sdlw  */
4*10517Sdlw 
5*10517Sdlw #include "complex"
6*10517Sdlw 
7*10517Sdlw pow_zz(r,a,b)
8*10517Sdlw dcomplex *r, *a, *b;
9*10517Sdlw {
10*10517Sdlw double logr, logi, x, y;
11*10517Sdlw double log(), exp(), cos(), sin(), atan2(), cabs();
12*10517Sdlw 
13*10517Sdlw logr = log( cabs(a->dreal, a->dimag) );
14*10517Sdlw logi = atan2(a->dimag, a->dreal);
15*10517Sdlw 
16*10517Sdlw x = exp( logr * b->dreal - logi * b->dimag );
17*10517Sdlw y = logr * b->dimag + logi * b->dreal;
18*10517Sdlw 
19*10517Sdlw r->dreal = x * cos(y);
20*10517Sdlw r->dimag = x * sin(y);
21*10517Sdlw }
22