According to following results, generating uniform random integers between 2 numbers using % operation is almost 3 times faster then using uniform_int_distribution.
Is there any good reason to use uniform_int_distribution?
Code:
#include <iostream>
#include <functional>
#include <vector>
#include <algorithm>
#include <random>
#include <cstdio>
#include <cstdlib>
using namespace std;
#define N 100000000
int main()
{
clock_t tic,toc;
for(int trials=0; trials<3; trials++)
{
cout<<"trial: "<<trials<<endl;
// uniform_int_distribution
{
int res = 0;
mt19937 gen(1);
uniform_int_distribution<int> dist(0,999);
tic = clock();
for(int i=0; i<N; i++)
{
int r = dist(gen);
res += r;
res %= 1000;
}
toc = clock();
cout << "uniform_int_distribution: "<<(float)(toc-tic)/CLOCKS_PER_SEC << endl;
cout<<res<<" "<<endl;
}
// simple modulus operation
{
int res = 0;
mt19937 gen(1);
tic = clock();
for(int i=0; i<N; i++)
{
int r = gen()%1000;
res += r;
res %= 1000;
}
toc = clock();
cout << "simple modulus operation: "<<(float)(toc-tic)/CLOCKS_PER_SEC << endl;
cout<<res<<" "<<endl;
}
cout<<endl;
}
}
Output:
trial: 0
uniform_int_distribution: 2.90289
538
simple modulus operation: 1.0232
575
trial: 1
uniform_int_distribution: 2.86416
538
simple modulus operation: 1.01866
575
trial: 2
uniform_int_distribution: 2.94309
538
simple modulus operation: 1.01809
575
Aucun commentaire:
Enregistrer un commentaire