Specifies if the solver must compute the true residual explicitly or not.
PetscErrorCode EPSSetTrueResidual(EPS eps,PetscBool trueres)
Logically Collective on EPS
|eps || - the eigensolver context
|trueres || - whether true residuals are required or not
Options Database Keys
|-eps_true_residual <boolean> || - Sets/resets the boolean flag 'trueres'
If the user sets trueres=PETSC_TRUE then the solver explicitly computes
the true residual for each eigenpair approximation, and uses it for
convergence testing. Computing the residual is usually an expensive
operation. Some solvers (e.g., Krylov solvers) can avoid this computation
by using a cheap estimate of the residual norm, but this may sometimes
give inaccurate results (especially if a spectral transform is being
used). On the contrary, preconditioned eigensolvers (e.g., Davidson solvers)
do rely on computing the true residual, so this option is irrelevant for them.
Index of all EPS routines
Table of Contents for all manual pages
Index of all manual pages