diff options
Diffstat (limited to 'Eigen/src/Eigenvalues/RealQZ.h')
| -rw-r--r-- | Eigen/src/Eigenvalues/RealQZ.h | 32 |
1 files changed, 31 insertions, 1 deletions
diff --git a/Eigen/src/Eigenvalues/RealQZ.h b/Eigen/src/Eigenvalues/RealQZ.h index a62071d42..b3a910dd9 100644 --- a/Eigen/src/Eigenvalues/RealQZ.h +++ b/Eigen/src/Eigenvalues/RealQZ.h @@ -552,7 +552,6 @@ namespace Eigen { m_T.coeffRef(l,l-1) = Scalar(0.0); } - template<typename MatrixType> RealQZ<MatrixType>& RealQZ<MatrixType>::compute(const MatrixType& A_in, const MatrixType& B_in, bool computeQZ) { @@ -616,6 +615,37 @@ namespace Eigen { } // check if we converged before reaching iterations limit m_info = (local_iter<m_maxIters) ? Success : NoConvergence; + + // For each non triangular 2x2 diagonal block of S, + // reduce the respective 2x2 diagonal block of T to positive diagonal form using 2x2 SVD. + // This step is not mandatory for QZ, but it does help further extraction of eigenvalues/eigenvectors, + // and is in par with Lapack/Matlab QZ. + if(m_info==Success) + { + for(Index i=0; i<dim-1; ++i) + { + if(m_S.coeff(i+1, i) != Scalar(0)) + { + JacobiRotation<Scalar> j_left, j_right; + internal::real_2x2_jacobi_svd(m_T, i, i+1, &j_left, &j_right); + + // Apply resulting Jacobi rotations + m_S.applyOnTheLeft(i,i+1,j_left); + m_S.applyOnTheRight(i,i+1,j_right); + m_T.applyOnTheLeft(i,i+1,j_left); + m_T.applyOnTheRight(i,i+1,j_right); + m_T(i+1,i) = m_T(i,i+1) = Scalar(0); + + if(m_computeQZ) { + m_Q.applyOnTheRight(i,i+1,j_left.transpose()); + m_Z.applyOnTheLeft(i,i+1,j_right.transpose()); + } + + i++; + } + } + } + return *this; } // end compute |