cuRAND expected an expression - c++

Question

I'm learning C++ for a project, and for my project I need to generate a random number on the GPU.
For this, I decided to use cuRAND.
However, I'm running into a small issue on this line:
random << <1, 1 >> >(time(NULL), gpu_x);
I got the error expected an expression on that line.
using this code, which I got from here:
__global__ void random(unsigned int seed, int* result) {
/* CUDA's random number library uses curandState_t to keep track of the seed value
we will store a random state for every thread */
curandState_t state;
/* we have to initialize the state */
curand_init(seed, /* the seed controls the sequence of random values that are produced */
0, /* the sequence number is only important with multiple cores */
0, /* the offset is how much extra we advance in the sequence for each call, can be 0 */
&state);
/* curand works like rand - except that it takes a state as a parameter */
*result = curand(&state) % MAX;
}
void Miner::GoMine() {
int* gpu_x;
cudaMalloc((void**)&gpu_x, sizeof(int));
/* invoke the GPU to initialize all of the random states */
random << <1, 1 >> >(time(NULL), gpu_x);
/* copy the random number back */
int x;
cudaMemcpy(&x, gpu_x, sizeof(int), cudaMemcpyDeviceToHost);
printf("Random number = %d.\n", x);
/* free the memory we allocated */
cudaFree(gpu_x);
}
As I am new to C++, I couldn't figure out what is going on.
I hope somebody here was able to help me?
Cheers

Answer 1

I managed to fix the issue by placing the CUDA related code in cuRAND.cu (Add -> New Item -> CUDA 9.0 -> Code -> CUDA C/C++ File).
I renamed the function void Miner::GoMine() to int cuRND()
I added some extra code so my entire cuRAND.cu file now looks like this:
// For the RNG using CUDA
#include <curand.h>
#include <curand_kernel.h>
#include <iomanip>
#include "sha256.h"
#ifndef __Kernel_CU__
#define __Kernel_CU__
#define MAX 100
__global__ void random(unsigned int seed, int* result) {
/* CUDA's random number library uses curandState_t to keep track of the seed value
we will store a random state for every thread */
curandState_t state;
/* we have to initialize the state */
curand_init(seed, /* the seed controls the sequence of random values that are produced */
0, /* the sequence number is only important with multiple cores */
0, /* the offset is how much extra we advance in the sequence for each call, can be 0 */
&state);
/* curand works like rand - except that it takes a state as a parameter */
*result = curand(&state) % MAX;
}
extern "C"
int cuRND() {
int* gpu_x;
cudaMalloc((void**)&gpu_x, sizeof(int));
/* invoke the GPU to initialize all of the random states */
random <<< 1, 1 >> >(time(NULL), gpu_x);
/* copy the random number back */
int x;
cudaMemcpy(&x, gpu_x, sizeof(int), cudaMemcpyDeviceToHost);
/* free the memory we allocated */
cudaFree(gpu_x);
return floor(99999999 * x);
}
#endif
I then proceeded to add this code to my miner.cpp (which is the file I need it in):
extern "C"
int cuRND();
I can now make a call to cuRND() from my miner.cpp.
Hit start, and I was off to the races!
Thanks for the help, I hope this answer can help somebody later down the road!