Multiplies two random matrices using Eigen, and displays the elapsed time for the multiplication only (not the creation of random matrices). Recommended compiliation (using g++): >> g++-mp-4.7 MatProdEigen.cpp -o MatProdEigen -I/path/to/eigen/ -O3 -DNDEBUG To multiply a 10x3 and 3x55 matrix: >> ./MatProdEigen 10 3 55

MatProdEigen.cpp

#include "Eigen/Dense"
#include <iostream>
#include <time.h>
using namespace Eigen;
using namespace std;

double diffclock(clock_t clock1,clock_t clock2)
{
  double diffticks=clock1-clock2;
	double diffms=(diffticks)/CLOCKS_PER_SEC;
	return diffms;
} 

int main( int argc, char *argv[] ) {
	if ( argc != 4 ) {
		printf("ERROR: Needs 3 arguments -- N, M, D\n");
		return -1;
	}
	
	int N = atoi( argv[1] );
	int D = atoi( argv[2] );
	int M = atoi( argv[3] );
	
	MatrixXd X = MatrixXd::Random( N, D);
 	MatrixXd Y = MatrixXd::Random( D, M); 
   
   
	clock_t starttime = clock(); 
  	MatrixXd R = X * Y;
  	clock_t endtime = clock();
  
  	cout << "Time elapsed: " << diffclock( endtime, starttime) \
        	<< " sec." << endl;
  	return 0;
}