[eigen] How to obtain the matrices Q and R of a QR decomposition

[Sebastian Birk <birk@xxxxxxxxxxxxxxxxxxxxx>]

Hi,

using Eigen 3 I would expect the following code to give me Q and R:

    MatrixXcd A = MatrixXcd::Random(m,m), Q, R;
    HouseholderQR<MatrixXcd> hh(A);

    // MATLAB economy size QR decomp.: [Q,R] = qr( A, 0 );
    Q = hh.householderQ();
    R = hh.matrixQR().triangularView<Upper>();

But when I take a look (via cout) at Q and R they both are exactly the
same as A.
Where is the flaw in this approach?

Thanks,
Sebastian

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