#include "cuda_runtime.h"

#include "device_launch_parameters.h"

#include <stdio.h>

#include <math.h>

#define N 64

#define TPB 32

__device__ float scale(int i, int n) {

return ((float)i) / (n - 1);

}

__device__ float distance(float x1, float x2) {

return sqrt((x2 - x1)*(x2 - x1));

}

__global__ void distanceKernel(float *d_out, float ref, int len)

{

const int i = blockIdx.x*blockDim.x + threadIdx.x;

const float x = scale(i, len);

d_out[i] = distance(x, ref);

printf("i=%2d: dist from %f to %f is %f.\n", i, ref, x, d_out[i]);

}

int main()

{

const float ref = 0.5f;

float *d_out = 0;

cudaMalloc(&d_out, N * sizeof(float));

distanceKernel << <N / TPB, TPB >> > (d_out, ref, N);

cudaFree(d_out);

return 0;

}