In the intermediate state A is reduced to tridiagonal form and B is transformed into a signature matrix. In compact storage format, these matrices are stored in T and D, respectively.

DS_MAT_A | - first problem matrix | |

DS_MAT_B | - second problem matrix | |

DS_MAT_T | - symmetric tridiagonal matrix of the reduced pencil | |

DS_MAT_D | - diagonal matrix (signature) of the reduced pencil | |

DS_MAT_Q | - pseudo-orthogonal transformation that reduces (A,B) to tridiagonal-diagonal form (intermediate step) or a real basis of eigenvectors |

0 | - QR iteration plus inverse iteration for the eigenvectors | |

1 | - HZ iteration | |

2 | - QR iteration plus pseudo-orthogonalization for the eigenvectors |

1. | - C. Campos and J. E. Roman, "Restarted Q-Arnoldi-type methods exploiting symmetry in quadratic eigenvalue problems", BIT Numer. Math. 56(4):1213-1236, 2016. |

Index of all DS routines

Table of Contents for all manual pages

Index of all manual pages