DSSetRefined#
Sets a flag to indicate that refined vectors must be computed.
Synopsis#
#include "slepcds.h"
PetscErrorCode DSSetRefined(DS ds,PetscBool ref)
Logically Collective
Input Parameters#
ds - the direct solver context
ref - a boolean flag
Notes#
Normally the vectors returned in DS_MAT_X are eigenvectors of the
projected matrix. With this flag activated, DSVectors() will return
the right singular vector of the smallest singular value of matrix
\(\tilde{A}-\theta I\), where \(\tilde{A}\) is the extended \((n+1)\times n\)
matrix and \(\theta\) is the Ritz value. This is used in the refined Ritz
approximation [Jia, 1997].
The default is PETSC_FALSE.
References#
Z. Jia. Refined iterative algorithms based on Arnoldi's process for large unsymmetric eigenproblems. Linear Algebra Appl., 259(1–3):1–23, 1997. doi:10.1016/S0024-3795(96)00238-8.
See Also#
DS: Direct Solver (or Dense System), DSVectors(), DSGetRefined()
Level#
advanced
Location#
src/sys/classes/ds/interface/dsbasic.c
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