如何在cuda内核函数中产生随机数（host端调用，device端产生）

最近，需要在kernel函数中调用浮点型的随机数。于是上网搜了下相关资料，一种方式是自己手动写一个随机数的__device__函数，然后在调用的时候调用这个函数。另一种，原来cuda在toolkit中给出了实现方式。

 

首先要用到三个函数：

curandCreateGenerator(&gen,CURAND_RNG_PSEUDO_DEFAULT); 

指定触发器为gen，随机方式为CURAND_RNG_PSEUDO_DEFAULT

curandSetPseudoRandomGeneratorSeed(gen,1234ULL);

指定种子为1234ULL(不同的种子产生的随机数列是不一样的)

curandGenerateUniform(gen,devData,n);

根据触发器gen，输出目标指针为devData，规模大小为n

/*

 * This program uses the host CURAND API to generate 100 

 * pseudorandom floats.

 */

#include <stdio.h>

#include <stdlib.h>

#include <cuda.h>

#include <curand.h>



#define CUDA_CALL(x) do { if((x)!=cudaSuccess) { \

    printf("Error at %s:%d\n",__FILE__,__LINE__);\

    return EXIT_FAILURE;}} while(0)

#define CURAND_CALL(x) do { if((x)!=CURAND_STATUS_SUCCESS) { \

    printf("Error at %s:%d\n",__FILE__,__LINE__);\

    return EXIT_FAILURE;}} while(0)



int main(int argc, char *argv[])

{

    size_t n = 100;

    size_t i;

    curandGenerator_t gen;

    float *devData, *hostData;



    /* Allocate n floats on host */

    hostData = (float *)calloc(n, sizeof(float));



    /* Allocate n floats on device */

    CUDA_CALL(cudaMalloc((void **)&devData, n*sizeof(float)));



    /* Create pseudo-random number generator */

    CURAND_CALL(curandCreateGenerator(&gen, 

                CURAND_RNG_PSEUDO_DEFAULT));

    

    /* Set seed */

    CURAND_CALL(curandSetPseudoRandomGeneratorSeed(gen, 

                1234ULL));



    /* Generate n floats on device */

    CURAND_CALL(curandGenerateUniform(gen, devData, n));



    /* Copy device memory to host */

    CUDA_CALL(cudaMemcpy(hostData, devData, n * sizeof(float),

        cudaMemcpyDeviceToHost));



    /* Show result */

    for(i = 0; i < n; i++) {

        printf("%1.4f ", hostData[i]);

    }

    printf("\n");



    /* Cleanup */

    CURAND_CALL(curandDestroyGenerator(gen));

    CUDA_CALL(cudaFree(devData));

    free(hostData);    

    return EXIT_SUCCESS;

}

样例输出后，产生的结果为：（待补）