13
edits
Changes
→Part 2 of Pi
'''source code''' can be found at [https://github.com/DoctorLai/coding_exercise/blob/master/parallel_monte_carlo_pi.cpp github]
<code><pre>int main()
{
srand(time(NULL));
const int N1 = 1000;
const int N2 = 100000;
int n = 0;
int c = 0;
Concurrency::critical_section cs;
// it is better that N1 >> N2 for better performance
Concurrency::parallel_for(0, N1, [&](int i)
{
int t = monte_carlo_count_pi(N2);
cs.lock(); // race condition
n += N2; // total sampling points
c += t; // points fall in the circle
cs.unlock();
});
cout << "pi ~= " << setprecision(9) << (double)c / n * 4.0 << endl;
return 0;
}</pre></code>
