petsc-3.4.4 2014-03-13

KSPBCGSL

Implements a slight variant of the Enhanced BiCGStab(L) algorithm in (3) and (2). The variation concerns cases when either kappa0**2 or kappa1**2 is negative due to round-off. Kappa0 has also been pulled out of the denominator in the formula for ghat.

References

1. G.L.G. Sleijpen, H.A. van der Vorst, "An overview of approaches for the stable computation of hybrid BiCG methods", Applied Numerical Mathematics: Transactions f IMACS, 19(3), pp 235-54, 1996. 2. G.L.G. Sleijpen, H.A. van der Vorst, D.R. Fokkema, "BiCGStab(L) and other hybrid Bi-CG methods", Numerical Algorithms, 7, pp 75-109, 1994. 3. D.R. Fokkema, "Enhanced implementation of BiCGStab(L) for solving linear systems of equations", preprint from www.citeseer.com.

Contributed by: Joel M. Malard, email jm.malard@pnl.gov

Options Database Keys

-ksp_bcgsl_ell <ell> Number of Krylov search directions, defaults to 2 - - KSPBCGSLSetEll()
-ksp_bcgsl_cxpol - Use a convex function of the MinRes and OR polynomials after the BiCG step instead of default MinRes -- KSPBCGSLSetPol()
-ksp_bcgsl_mrpoly - Use the default MinRes polynomial after the BiCG step -- KSPBCGSLSetPol()
-ksp_bcgsl_xres <res> Threshold used to decide when to refresh computed residuals - - KSPBCGSLSetXRes()
-ksp_bcgsl_pinv <true/false> - (de)activate use of pseudoinverse -- KSPBCGSLSetUsePseudoinverse()

See Also

KSPCreate(), KSPSetType(), KSPType (for list of available types), KSP, KSPFGMRES, KSPBCGS, KSPSetPCSide(), KSPBCGSLSetEll(), KSPBCGSLSetXRes()

Level:beginner
Location:
src/ksp/ksp/impls/bcgsl/bcgsl.c
Index of all KSP routines
Table of Contents for all manual pages
Index of all manual pages