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Bug 815 - Documentation of FullPivLu needs correction on the permutation matrices
Summary: Documentation of FullPivLu needs correction on the permutation matrices
Status: RESOLVED FIXED
Alias: None
Product: Eigen
Classification: Unclassified
Component: Documentation (show other bugs)
Version: unspecified
Hardware: All All
: Normal Unknown
Assignee: Nobody
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2014-05-30 17:43 UTC by Allan Leal
Modified: 2014-06-01 00:10 UTC (History)
3 users (show)



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Description Allan Leal 2014-05-30 17:43:59 UTC
In http://eigen.tuxfamily.org/dox/classEigen_1_1FullPivLU.html, please correct from:

A = PLUQ

to

A = P^TLUQ^T

#include <iostream>
#include <Eigen/Dense>
using namespace Eigen;
using namespace std;

int main()
{
    MatrixXd M = MatrixXd::Random(5, 5);

    FullPivLU<MatrixXd> lu(M);

    const MatrixXd L = lu.matrixLU().triangularView<UnitLower>();
    const MatrixXd U = lu.matrixLU().triangularView<Upper>();
    const MatrixXd P = lu.permutationP();
    const MatrixXd Q = lu.permutationQ();

    cout << "M = \n" << M << endl;
    cout << "PLUQ = \n" << P*L*U*Q << endl;
    cout << "P^TLUQ^T = \n" << P.transpose()*L*U*Q.transpose() << endl;

    return 0;
}
Comment 1 Jitse Niesen 2014-06-01 00:10:55 UTC
Thank you for your report. This should now be fixed (changeset 3d06c6dec4f3 for the dev branch and changeset bf87a7a3bc64 for 3.2).

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