Solving linear equations

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jonatan.olofsson Registered Member Posts 2 Karma 0 OS	Solving linear equations Thu Jun 23, 2011 7:00 am Hi, I'm trying to implement some matrix equations Code: Select all `// [2] eq. 9.7a: L = R\B'S L.noalias() = R.partialPivLu().solve( m.B.transpose()*S );` However, the above code yields the following compile error: ...eigen/Eigen/src/Core/DenseCoeffsBase.h:508: error: cannot convert 'const Eigen::ReturnByValue<Eigen::internal::solve_retval_base<Eigen::PartialPivLU<Eigen::Matrix<double, 3, 3, 0, 3, 3> >, Eigen::Matrix<double, 9, 1, 0, 9, 1> > >::YOU_ARE_TRYING_TO_ACCESS_A_SINGLE_COEFFICIENT_IN_A_SPECIAL_EXPRESSION_WHERE_THAT_IS_NOT_ALLOWED_BECAUSE_THAT_WOULD_BE_INEFFICIENT' to 'double' in assignment The headers I'm including are Code: Select all `#include <Eigen/Core> #include <Eigen/LU>` Does anyone have any suggestions as to what I'm doing wrong? Best regards, Jonatan Olofsson
ggael Moderator Posts 3447 Karma 19 OS	Re: Solving linear equations Thu Jun 23, 2011 7:57 am you should evaluate m.B.transpose()S: (m.B.transpose()S).eval()* and no need for the noalias here. EDIT: the evaluation should be done for you, I'm filling a bug report.
jonatan.olofsson Registered Member Posts 2 Karma 0 OS	Re: Solving linear equations Thu Jun 23, 2011 8:21 am Thank you very much ggael, it did indeed solve my problem! I've been scratching my head for quite some time over this now =) Best regards, Jonatan

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