| // g++ -O3 -DNDEBUG benchmarkX.cpp -o benchmarkX && time ./benchmarkX | 
 |  | 
 | #include <iostream> | 
 |  | 
 | #include <Eigen/Core> | 
 |  | 
 | 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::internal::random<int>(0, 10); | 
 |     c = Eigen::internal::random<int>(0, 10); | 
 |     nr = Eigen::internal::random<int>(50, 80); | 
 |     nc = Eigen::internal::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; | 
 | } |