source: pacpussensors/trunk/Vislab/lib3dv-1.2.0/lib3dv/eigen/bench/benchmarkXcwise.cpp

// g++ -O3 -DNDEBUG benchmarkX.cpp -o benchmarkX && time ./benchmarkX

#include <iostream>
#include <Eigen/Core>

using namespace std;
using namespace Eigen;

#ifndef VECTYPE
#define VECTYPE VectorXLd
#endif

#ifndef VECSIZE
#define VECSIZE 1000000
#endif

#ifndef REPEAT
#define REPEAT 1000
#endif

int main(int argc, char *argv[])
{
        VECTYPE I = VECTYPE::Ones(VECSIZE);
        VECTYPE m(VECSIZE,1);
        for(int i = 0; i < VECSIZE; i++)
        {
                m[i] = 0.1 * i/VECSIZE;
        }
        for(int a = 0; a < REPEAT; a++)
        {
                m = VECTYPE::Ones(VECSIZE) + 0.00005 * (m.cwise().square() + m/4);
        }
        cout << m[0] << endl;
        return 0;
}