#include <u.h>#include <libc.h>#include "map.h" voidccubrt(double zr, double zi, double *wr, double *wi){	double r, theta;	theta = atan2(zi,zr);	r = cubrt(hypot(zr,zi));	*wr = r*cos(theta/3);	*wi = r*sin(theta/3);}