petsc-3.12.5 2020-03-29
PCFieldSplitSetGKBDelay
Sets the delay in the lower bound error estimate in the generalized Golub-Kahan bidiagonalization preconditioner.
Synopsis
#include "petscpc.h"
PetscErrorCode PCFieldSplitSetGKBDelay(PC pc,PetscInt delay)
Collective on PC
Notes
The algorithm uses a lower bound estimate of the error in energy norm as stopping criterion. The lower bound of the error ||u-u^k||_H
is expressed as a truncated sum. The error at iteration k can only be measured at iteration (k + delay), and thus the algorithm needs
at least (delay + 1) iterations to stop. For more details on the generalized Golub-Kahan bidiagonalization method and its lower bound stopping criterion, please refer to
[Ar13] Generalized Golub-Kahan bidiagonalization and stopping criteria, SIAM J. Matrix Anal. Appl., Vol. 34, No. 2, pp. 571-592, 2013.
Input Parameters
| pc | - the preconditioner context
|
| delay | - the delay window in the lower bound estimate
|
Options Database
-pc_fieldsplit_gkb_delay -default is 5
See Also
PCFIELDSPLIT, PCFieldSplitSetGKBNu(), PCFieldSplitSetGKBTol(), PCFieldSplitSetGKBMaxit()
Level
intermediate
Location
src/ksp/pc/impls/fieldsplit/fieldsplit.c
Implementations
PCFieldSplitSetGKBDelay_FieldSplit in src/ksp/pc/impls/fieldsplit/fieldsplit.c
Index of all PC routines
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Index of all manual pages