1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
|
#include <cuda.h>
#include <stdio.h>
#include <stdlib.h>
__device__ void f2(int idx, float x_s[4])
{
if(idx>0) {
printf("%i %.2e %.2e\n", idx, x_s[idx], x_s[idx-1]);
} else {
printf("%i %.2e\n", idx, x_s[idx]);
}
}
__global__ void f1(float *x_d)
{
int idx = blockIdx.x * blockDim.x + threadIdx.x;
__shared__ float x_s[4];
x_s[idx] = x_d[idx];
__syncthreads();
//printf("%i %.2e %.2e\n", idx, x_d[idx], x_s[idx]);
f2(idx, x_s);
}
int main()
{
float *x_h, *x_d;
int nx = 4;
// allocate, copy
cudaSetDevice(0);
x_h = (float *) malloc(sizeof(float)*nx);
for(int ii=0; ii<nx; ii++) {
x_h[ii] = ii;
printf("%i %.2e\n", ii, x_h[ii]);
}
printf("\n");
cudaMalloc((void**) &x_d, sizeof(float)*nx);
cudaMemcpy(x_d, x_h, sizeof(float)*nx, cudaMemcpyHostToDevice);
// run kernel
f1 <<< 1, 4 >>> (x_d);
// free
cudaFree(x_d);
free(x_h);
}
|
