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@lucidfrontier45
Last active October 8, 2022 10:41
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cpp benchmark
#include <chrono>
#include <iostream>
#include <random>
double dot(const std::vector<double> &x, const std::vector<double> &y)
{
auto n = x.size();
double s = 0.0;
for (size_t i = 0; i < n; i++)
{
s += x[i] * y[i];
}
return s;
}
std::uniform_real_distribution<> dist(0.0, 1.0);
template <class URBG>
std::vector<double> uniform_rand(size_t n, URBG &engine)
{
std::vector<double> v(n);
for (size_t i = 0; i < n; i++)
{
v[i] = dist(engine);
}
return v;
}
int main()
{
std::random_device seed_gen;
std::default_random_engine engine(0);
double s = 0.0;
auto start = std::chrono::system_clock::now();
for (size_t i = 0; i < 10000; i++)
{
auto x = uniform_rand(10000, engine);
auto y = uniform_rand(10000, engine);
s += dot(x, y);
}
auto end = std::chrono::system_clock::now();
double elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(end - start).count() / 1000.0;
std::cout << "s = " << s << std::endl;
std::cout << "elapsed = " << elapsed << "[sec]" << std::endl;
}
#include <chrono>
#include <iostream>
#include <vector>
int main()
{
double s = 0.0;
auto start = std::chrono::system_clock::now();
for (size_t i = 0; i < 5000; i++)
{
std::vector<double> v(1000000);
v[0] = 10;
}
auto end = std::chrono::system_clock::now();
double elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(end - start).count() / 1000.0;
std::cout << "elapsed = " << elapsed << "[sec]" << std::endl;
}
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