Mandelbrot Set calculated with CUDA: using resources from CUDA by Example at https://developer.nvidia.com/cuda-example

mandelbrot.cu

#include "../common/book.h"
#include "../common/cpu_bitmap.h"

#define DIM 1000

//From Wikipedia's article on the Mandelbrot Set:
__device__ int mandelbrot( int xa, int ya, float s, float xpos, float ypos) {
	float x0 = s * (float) (DIM/2 -xa)/((float)DIM/2) + xpos;
	float y0 = s * (float)(DIM/2 -ya )/((float)DIM/2) + ypos;
	int m = 0;
	float x = 0.0;
	float y = 0.0;
	int i = 0;
	int maxI = 1000;
	while (((x*x + y*y) <= 2*2) && (i < maxI)) {
		float xtemp = x*x - y*y + x0;
		y = 2*x*y + y0;
		x = xtemp;
		i++;
		m = i;
	}
	return m;

}

__global__ void kernel ( unsigned char *ptr, float s, float xpos, float ypos) {
	//map from blockIDx to pixel positio0n
	int x = blockIdx.x;
	int y = blockIdx.y;
	int offset = x + y * gridDim.x;
	
	int mValue = mandelbrot( x, y, s, xpos, ypos);
	int red = 0;
	int blue = 0;
	int green = 0;
	if (mValue%3 == 0) blue = 1;
	if (mValue%3 == 1) red = 1;
	if (mValue%3 == 2) green = 1;
	ptr[offset*4 + 0] = red * 255 * mValue / 16;
	ptr[offset*4 + 1] = blue * 255 * mValue/16;
	ptr[offset*4 + 2] = green * 255 * mValue/16;
	ptr[offset*4 + 3] = 255;
}

int main ( int argc,char *argv[] ) {
	CPUBitmap bitmap( DIM, DIM );
	unsigned char *dev_bitmap;
	float s = atof(argv[1]);
	float xpos = atof(argv[2]);
	float ypos = atof(argv[3]);
	
	HANDLE_ERROR( cudaMalloc( (void**)&dev_bitmap, bitmap.image_size()));
	
	dim3 grid(DIM, DIM);
	
	kernel<<<grid, 1>>>( dev_bitmap, s, xpos, ypos );
	HANDLE_ERROR( cudaMemcpy( bitmap.get_ptr(), dev_bitmap, bitmap.image_size(), cudaMemcpyDeviceToHost ) ) ;
	bitmap.display_and_exit();
	HANDLE_ERROR( cudaFree( dev_bitmap ) );
	return 0;
}