Mandelbrot-NeedsCorrections.c

#include <omp.h>
#define NPOINTS 1000
#define MXITR 1000

void testpoint(void);
struct d_complex{
double r; double i;
};
struct d_complex c;
int numoutside = 0;
int main(){
    int i, j;
    double area, error, eps = 1.0e-5;
    #pragma omp parallel for default(shared) private(c,eps)
    for (i=0; i<NPOINTS; i++) {
        for (j=0; j<NPOINTS; j++) {
            c.r = -2.0+2.5*(double)(i)/(double)(NPOINTS)+eps;
            c.i = 1.125*(double)(j)/(double)(NPOINTS)+eps;
            testpoint();
        }
    }
    area=2.0*2.5*1.125*(double)(NPOINTS*NPOINTS-numoutside)/(double)(NPOINTS*NPOINTS);
    error=area/(double)NPOINTS;
    printf("%f", area);
}

void testpoint(void){
    struct d_complex z;
    int iter;
    double temp;
    z=c;
    for (iter=0; iter<MXITR; iter++){
        temp = (z.r*z.r)-(z.i*z.i)+c.r;
        z.i = z.r*z.i*2+c.i;
        z.r = temp;
        if ((z.r*z.r+z.i*z.i)>4.0) {
            numoutside++;
        break;
        }
    }
}