KSPEKSMSetShift#
Sets the value of the shift \(\varsigma\) that will be used for the internal linear solves in the EKSM solver.
Synopsis#
#include "petscksp.h"
PetscErrorCode KSPEKSMSetShift(KSP ksp, PetscScalar shift)
Logically Collective
Input Parameters#
ksp - the Krylov space solver context
shift - the value of the shift, \(\varsigma\)
Options Database Key#
-ksp_eksm_shift shift - the value of the shift
Notes#
The extended Krylov subspace method needs to solve linear systems with the matrix \(K + \varsigma M\) using an auxiliary KSP object,
see KSPEKSMGetKSP(). The scalar value \(\varsigma\) is provided with this function. If not set, the default
is to use a value of \(\varsigma\) equal to the centroid (or center of mass) of all shifts \(\sigma_i\) provided
by the user in MatCreateNestFromMultipleShifts().
See Also#
KSP: Linear System Solvers, KSPEKSM, KSPEKSMGetKSP(), KSPEKSMGetShift(), MatCreateNestFromMultipleShifts()
Level#
intermediate
Location#
Implementations#
KSPEKSMSetShift_EKSM() in src/ksp/ksp/impls/eksm/eksm.c
Index of all KSP routines
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Index of all manual pages