| // g++ -O3 -DNDEBUG -DMATSIZE=<x> benchmark.cpp -o benchmark && time ./benchmark | 
 | #include <Eigen/Array> | 
 |  | 
 | #ifndef MATSIZE | 
 | #define MATSIZE 3 | 
 | #endif | 
 |  | 
 | using namespace std; | 
 | using namespace Eigen; | 
 |  | 
 | #ifndef REPEAT | 
 | #define REPEAT 40000000 | 
 | #endif | 
 |  | 
 | #ifndef SCALAR | 
 | #define SCALAR double | 
 | #endif | 
 |  | 
 | int main(int argc, char *argv[]) | 
 | { | 
 |     Matrix<SCALAR,MATSIZE,MATSIZE> I = Matrix<SCALAR,MATSIZE,MATSIZE>::Ones(); | 
 |     Matrix<SCALAR,MATSIZE,MATSIZE> m; | 
 |     for(int i = 0; i < MATSIZE; i++) | 
 |         for(int j = 0; j < MATSIZE; j++) | 
 |         { | 
 |             m(i,j) = (i+MATSIZE*j); | 
 |         } | 
 |     asm("#begin"); | 
 |     for(int a = 0; a < REPEAT; a++) | 
 |     { | 
 |         m = Matrix<SCALAR,MATSIZE,MATSIZE>::Ones() + 0.00005 * (m + (m*m)); | 
 |     } | 
 |     asm("#end"); | 
 |     cout << m << endl; | 
 |     return 0; | 
 | } |