I get the following error when trying to compile the following code:

MatrixXd a(3,3);
MatrixXd b(1,3);
a << -1,1,2,
-2,3,1,
4,0,3;
b << 3, 4, 5;
cout << (a.col(0) - b(0)) << endl;

error: no match for ‘operator-’ in ‘((Eigen::DenseBase<Eigen::Matrix<double, -0x000000001, -0x000000001, 0, -0x000000001, -0x000000001> >*)(& a))->Eigen::DenseBase<Derived>::col [with Derived = Eigen::Matrix<double, -0x000000001, -0x000000001, 0, -0x000000001, -0x000000001>](1) - ((Eigen::DenseCoeffsBase<Eigen::Matrix<double, -0x000000001, -0x000000001, 0, -0x000000001, -0x000000001>, 1>*)(& b))->Eigen::DenseCoeffsBase<Derived, 1>::operator() [with Derived = Eigen::Matrix<double, -0x000000001, -0x000000001, 0, -0x000000001, -0x000000001>](1)’


In short, i want to substract a scalar from coefficients for a certain column.

I'm quite new to this, so any help would be appreciated.

Thanks.

Eric

figured it out. Need to convert to arrays before doing the substration

cout << a.col(0).array() - b(0) << endl;