starpu-max/julia/mandelbrot/cpu_mandelbrot.c

#include <stdio.h>
#include <starpu.h>
#include <math.h>

void cpu_mandelbrot(void *descr[], void *cl_arg)
{
        long long int *pixels;
	float *params;

        pixels = (long long int *)STARPU_MATRIX_GET_PTR(descr[0]);
	params = (float *)STARPU_MATRIX_GET_PTR(descr[1]);

        int width = STARPU_MATRIX_GET_NX(descr[0]);
        int height = STARPU_MATRIX_GET_NY(descr[0]);
        
        int ldP = STARPU_MATRIX_GET_LD(descr[0]);

        float centerr = params[0];
        float centeri = params[1];
        float offset = params[2];
        float dim = params[3];
        float zoom = width * 0.25296875;
        float diverge = 4.0;
        int max_iter = (width/2) * 0.049715909 * log10(zoom);

        int x,y,n;

        for (y = 0; y < height; y++){
                for (x = 0; x < width; x++){
                        float cr = centerr + (x - (dim/2))/zoom;
                        float ci = centeri + (y+offset - (dim/2))/zoom;
                        float zr = cr;
                        float zi = ci;
                        
                        for (n = 0; n <= max_iter; n++) {
				if (zr*zr + zi*zi>diverge) break;
                                float tmp = zr*zr - zi*zi + cr;
                                zi = 2*zr*zi + ci;
                                zr = tmp;
                        }
			int color;
			if (n<max_iter)
				color = round(15.*n/max_iter);
			else
				color = 0;
			pixels[x*ldP + y] = color;
		}
	}
}

char* CPU = "cpu_mandelbrot";
char* GPU = "gpu_mandelbrot";
extern char *starpu_find_function(char *name, char *device) {
	if (!strcmp(device,"gpu")) return GPU;
	return CPU;
}