最近在寫算法時,發現OpenMP + C++ functional 可以瞬間構造一個線程池,並執行風馬牛不相及的事情。看來,有必要好好思考一下今後算法優化的事情了!
在 g++下通過編譯
#include <iostream>
#include <functional>
#include <vector>
using namespace std;
void fun (int a, int b)
{
cout<< "fun exec :"<< a << '+' << b << '=' << a + b <<endl;
}
class C{
private:
float m_c = 2.0f;
public:
void mp( float d)
{
cout<<"c::mp exec :"<< m_c << 'x' << d << '=' << m_c * d <<endl;
}
};
int main(int argc, char * argv[])
{
const int task_groups = 5;
C c [task_groups];
vector<function<void (void) > > tasks;
for (int i=0;i<task_groups;++i)
{
tasks.push_back(bind( fun , 10, i * 10 ) );
tasks.push_back(bind( &C::mp , &c[i], i*2.0f ) );
tasks.push_back(bind(
[=] (void) {cout << "lambada :" <<i << endl; }
) );
}
size_t sz = tasks.size();
#pragma omp parallel for
for (size_t i=0;i<sz;++i)
{
tasks[i]();
}
return 0;
}
輸出:
fun exec :10+0=10
c::mp exec :2x0=0
lambada :0
fun exec :10+10=20
c::mp exec :2x2=4
lambada :1
fun exec :10+20=30
c::mp exec :2x4=8
lambada :2
fun exec :10+30=40
c::mp exec :2x6=12
lambada :3
fun exec :10+40=50
c::mp exec :2x8=16
lambada :4
編譯器選項:
-fopenmp
鏈接選項:
-lgomp