CODEWITHSUNDEEP
c++cuda
user1536720
user1536720

Reputation: 93

curand, thrust::random

I want to get random uniform number using drand48 in .cu format files why I always give me 3.90799e-14 this value

my code is in ran_uniform_test.cu

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

Upvotes: 0

Views: 757

Answers (1)

user7116
user7116

Reputation: 64068

You should call srand48 (or seed48, or lcong48) prior to using drand48:

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.

Used like so:

#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;
}

Upvotes: 2

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