EPSComputeError#
Computes the error (based on the residual norm) associated with the i-th computed eigenpair.
Synopsis#
#include "slepceps.h"
PetscErrorCode EPSComputeError(EPS eps,PetscInt i,EPSErrorType type,PetscReal *error)
Collective
Input Parameters#
eps - the linear eigensolver context
i - the solution index
type - the type of error to compute, see
EPSErrorType
Output Parameter#
error - the error
Notes#
The error can be computed in various ways, all of them based on the residual norm \(\|Ax-\lambda Bx\|_2\) where \((\lambda,x)\) is the approximate eigenpair.
If the computation of left eigenvectors was enabled with EPSSetTwoSided(),
then the error will be computed using the maximum of the value above and
the left residual norm \(\|y^*A-\lambda y^*B\|_2\), where \(y\) is the approximate left
eigenvector.
See Also#
EPS: Eigenvalue Problem Solver, EPSErrorType, EPSSolve(), EPSGetErrorEstimate(), EPSSetTwoSided()
Level#
beginner
Location#
Examples#
src/eps/tutorials/ex1.c
src/eps/tutorials/ex19.c
src/eps/tutorials/ex31.c
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