KSPBCGSLSetEll#
Sets the number of search directions to use in the KSPBCGSL
Krylov solver
Synopsis#
#include "petscksp.h"
PetscErrorCode KSPBCGSLSetEll(KSP ksp, PetscInt ell)
Logically Collective
Input Parameters#
Options Database Key#
-ksp_bcgsl_ell ell - Number of Krylov search directions
Notes#
For large ell
it is common for the polynomial update problem to become singular (due to happy breakdown for smallish
test problems, but also for larger problems). Consequently, by default, the system is solved by using the pseudoinverse, which
allows the iteration to complete successfully. See KSPBCGSLSetUsePseudoinverse()
to switch to a conventional solve.
See Also#
KSP: Linear System Solvers, KSPBCGSLSetUsePseudoinverse()
, KSP
, KSPBCGSL
, KSPBCGSLSetPol()
, KSPBCGSLSetXRes()
Level#
intermediate
Location#
src/ksp/ksp/impls/bcgsl/bcgsl.c
Index of all KSP routines
Table of Contents for all manual pages
Index of all manual pages