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#

[Jia97]

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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