请问 这段 Eigen 程序哪里错了

Question

#include
#include
#include

using namespace std;
using namespace Eigen;

int main(int, char *[])
{
MatrixXd mat(2, 3);
mat << 1, 2, 3,
4, 5, 6;
MatrixXd u(3, 1);
u << 1, 2, 3;

    //用vector就可以

/*VectorXd u(3);
u << 1, 2, 3;
cout << u;*/

MatrixXd mf = mat * u;

cout << mf;

system("pause");
}

Answer 1

http://bbs.csdn.net/topics/392092461