Return to cubrt.c CVS log

Up to [Research Unix] / researchv10no / cmd / map / libmap

Annotation of researchv10no/cmd/map/libmap/cubrt.c, revision 1.1.1.1

1.1       root        1: #include "map.h"
                      2: 
                      3: double
                      4: cubrt(double a)
                      5: {
                      6:        double x,y,x1;
                      7:        if(a==0) 
                      8:                return(0.);
                      9:        y = 1;
                     10:        if(a<0) {
                     11:                y = -y;
                     12:                a = -a;
                     13:        }
                     14:        while(a<1) {
                     15:                a *= 8;
                     16:                y /= 2;
                     17:        }
                     18:        while(a>1) {
                     19:                a /= 8;
                     20:                y *= 2;
                     21:        }
                     22:        x = 1;
                     23:        do {
                     24:                x1 = x;
                     25:                x = (2*x1+a/(x1*x1))/3;
                     26:        } while(fabs(x-x1)>10.e-15);
                     27:        return(x*y);
                     28: }

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.