Hi All
I’m studying this beginners tutorial and tried one of the first examples:
#include <assert.h>
#include <stdio.h>
int main(void)
{
float *a_h, *b_h; // host data
float *a_d, *b_d; // device data
int N = 14, nBytes, i;
nBytes = N*sizeof(float);
a_h = (float *)malloc(nBytes);
b_h = (float *)malloc(nBytes);
cudaMalloc((void **) &a_d, nBytes);
cudaMalloc((void **) &b_d, nBytes);
for (i=0; i<N; i++) a_h[i] = 100.f + i;
cudaMemcpy(a_d, a_h, nBytes, cudaMemcpyHostToDevice);
cudaMemcpy(b_d, a_d, nBytes, cudaMemcpyDeviceToDevice);
cudaMemcpy(b_h, b_d, nBytes, cudaMemcpyDeviceToHost);
for (i=0; i< N; i++) {
printf("%f == %f\n", a_h[i], b_h[i]);
//assert( a_h[i] == b_h[i] );
}
free(a_h); free(b_h); cudaFree(a_d); cudaFree(b_d);
return 0;
}
On my MacBook pro I can compile and run it, however it prints:
100.000000 == 0.000000
101.000000 == 0.000000
102.000000 == 0.000000
103.000000 == 0.000000
104.000000 == 0.000000
105.000000 == 0.000000
106.000000 == 0.000000
107.000000 == 0.000000
108.000000 == 0.000000
109.000000 == 0.000000
110.000000 == 0.000000
111.000000 == 0.000000
112.000000 == 0.000000
113.000000 == 0.000000
Any suggestions what might go wrong with this code ?
Thnx
LuCa
It works ok on my Macbook Pro, are you sure that CUDA is installed properly?
What is the output of the deviceQuery SDK example?
#include <cuda_runtime.h>
#include <stdlib.h>
#include <stdio.h>
int main(void)
{
float *a_h, *b_h; // host data
float *a_d, *b_d; // device data
int N = 14, nBytes, i;
nBytes = N*sizeof(float);
a_h = (float *)malloc(nBytes);
b_h = (float *)malloc(nBytes);
cudaMalloc((void **) &a_d, nBytes);
cudaMalloc((void **) &b_d, nBytes);
for (i=0; i<N; i++) a_h[i] = 100.f + i;
cudaMemcpy(a_d, a_h, nBytes, cudaMemcpyHostToDevice);
cudaMemcpy(b_d, a_d, nBytes, cudaMemcpyDeviceToDevice);
cudaMemcpy(b_h, b_d, nBytes, cudaMemcpyDeviceToHost);
for (i=0; i< N; i++) {
printf("%f == %f\n", a_h[i], b_h[i]);
//assert( a_h[i] == b_h[i] );
}
free(a_h); free(b_h); cudaFree(a_d); cudaFree(b_d);
return 0;
}
nvcc -os sample_copy sample_copy.c
./sample_copy
100.000000 == 100.000000
101.000000 == 101.000000
102.000000 == 102.000000
103.000000 == 103.000000
104.000000 == 104.000000
105.000000 == 105.000000
106.000000 == 106.000000
107.000000 == 107.000000
108.000000 == 108.000000
109.000000 == 109.000000
110.000000 == 110.000000
111.000000 == 111.000000
112.000000 == 112.000000
113.000000 == 113.000000
CUDA Device #0
CUDA is not installed properly on your system:
Reinstall the toolkit and be sure that the CUDA Kext is selected during installation (under customize option).
to bad :(
If I download the toolkit via [url=“CUDA Toolkit 11.7 Update 1 Downloads | NVIDIA Developer ”]http://www.nvidia.com/object/cuda_get.html[/url] there are no questions asked during installation. Is there an alternative installation procedure ?
Should the test code not also work in emulation mode ?
BTW, is my graphics card good enough ?
GeForce 8600M GT:
Chipset Model: GeForce 8600M GT
thnx a lot!!
CUDA is not installed properly on your system:
Name: Device Emulation (CPU)
Reinstall the toolkit and be sure that the CUDA Kext is selected during installation (under customize option).
I did the installation again and finally noticed the ‘customization’ button :) and enabled Kext!
Now it works!!!
Thnx a lot
LuCa
When you install, in the installation type screen, there is a customize button ( left lower corner).