c++ - curand, thrust::随机

Question

我想在 .cu 格式文件中使用 drand48 获得随机统一数，为什么我总是给我 3.90799e-14 这个值

我的代码在 ran_uniform_test.cu 中

#include <iostream>
int main( int argc, char** argv) 
{ 
    std::cout<<drand48()<<"\n"; 
    return 0;
}

Answer 1

你应该调用srand48 (或 seed48，或 lcong48)在使用 drand48 之前:

The srand48(), seed48() and lcong48() are initialisation entry points, one of which should be invoked before either drand48(), lrand48() or mrand48() is called. (Although it is not recommended practice, constant default initialiser values will be supplied automatically if drand48(), lrand48() or mrand48() is called without a prior call to an initialisation entry point.) The erand48(), nrand48() and jrand48() functions do not require an initialisation entry point to be called first.

这样使用:

#include <iostream>
#include <ctime>
#include <cstdlib>

int main(int argc, char *argv[])
{
    // A common random seed strategy is to use the current time
    srand48(time(NULL));

    std::cout << drand48() << std::endl;
    std::cout << drand48() << std::endl;
    std::cout << drand48() << std::endl;
    std::cout << drand48() << std::endl;

    return 0;
}