Hello all,

In matlab i have:

[q r]=qr( mymat , 0 ); % it's a 1024x6 --> 'q' will be the same size as 'mymat'

but in eigen, i cannot do that

Eigen::HouseholderQR<MatrixXd> qr(mymat );
MatrixXd q=qr.householderQ(); //it will be a 1024x1024

what you want is the "thin" Q. You can workaround with:

MatrixXd q = MatrixXd::Identity(mat.rows(), mat.cols());
q.applyOnTheLeft( qr.householderQ() );