1 28994509 2004-04-21 devnull #include <u.h>
2 28994509 2004-04-21 devnull #include <libc.h>
3 28994509 2004-04-21 devnull #include "map.h"
6 28994509 2004-04-21 devnull cubrt(double a)
8 28994509 2004-04-21 devnull double x,y,x1;
10 28994509 2004-04-21 devnull return(0.);
12 28994509 2004-04-21 devnull if(a<0) {
16 28994509 2004-04-21 devnull while(a<1) {
20 28994509 2004-04-21 devnull while(a>1) {
27 28994509 2004-04-21 devnull x = (2*x1+a/(x1*x1))/3;
28 28994509 2004-04-21 devnull } while(fabs(x-x1)>10.e-15);
29 28994509 2004-04-21 devnull return(x*y);