| // g++ -O3 -DNDEBUG benchmarkX.cpp -o benchmarkX && time ./benchmarkX | 
 |  | 
 | #include <Eigen/Array> | 
 |  | 
 | using namespace std; | 
 | using namespace Eigen; | 
 |  | 
 | #ifndef REPEAT | 
 | #define REPEAT 10000 | 
 | #endif | 
 |  | 
 | #ifndef SCALAR | 
 | #define SCALAR float | 
 | #endif | 
 |  | 
 | int main(int argc, char *argv[]) | 
 | { | 
 |   typedef Matrix<SCALAR, Eigen::Dynamic, Eigen::Dynamic> Mat; | 
 |   Mat m(100, 100); | 
 |   m.setRandom(); | 
 |  | 
 |   for(int a = 0; a < REPEAT; a++) | 
 |   { | 
 |     int r, c, nr, nc; | 
 |     r = Eigen::ei_random<int>(0,10); | 
 |     c = Eigen::ei_random<int>(0,10); | 
 |     nr = Eigen::ei_random<int>(50,80); | 
 |     nc = Eigen::ei_random<int>(50,80); | 
 |     m.block(r,c,nr,nc) += Mat::Ones(nr,nc); | 
 |     m.block(r,c,nr,nc) *= SCALAR(10); | 
 |     m.block(r,c,nr,nc) -= Mat::constant(nr,nc,10); | 
 |     m.block(r,c,nr,nc) /= SCALAR(10); | 
 |   } | 
 |   cout << m[0] << endl; | 
 |   return 0; | 
 | } |