-ksp_specest_minfactor <0.9> | - Multiplier on the minimum eigen/singular value | |

-ksp_specest_maxfactor <1.1> | - Multiplier on the maximum eigen/singular value | |

-ksp_specest_richfactor <1> | - Multiplier on the richimum eigen/singular value | |

-specest_ksp_type <type> | - KSP used to estimate the spectrum (usually CG or GMRES) | |

-speccheap_ksp_type <type> | - KSP used as a cheap smoother once the spectrum has been estimated (usually Chebyshev or Richardson) | |

see KSPSolve() for more | - Notes: This KSP estimates the extremal singular values on the first pass, then uses them to configure a smoother that uses fewer dot products. It is intended for use on the levels of multigrid, especially at high process counts, where dot products are very expensive. |

The same PC is used for both the estimator and the cheap smoother, it is only set up once. There are no options keys for -specest_pc_ or speccheap_pc_ since it is the same object as -pc_.

** Level:intermediate
Location:**src/ksp/ksp/impls/specest/specest.c

Index of all KSP routines

Table of Contents for all manual pages

Index of all manual pages