KSPBCGSL#

Implements a slight variant of the Enhanced BiCGStab(L) algorithm in (3) and (2). The variation concerns cases when either kappa02 or kappa12 is negative due to round-off. Kappa0 has also been pulled out of the denominator in the formula for ghat.

References#

  • **** -*** 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), 1996.

  • **** -*** G.L.G. Sleijpen, H.A. van der Vorst, D.R. Fokkema, “BiCGStab(L) and other hybrid BiCG methods”, Numerical Algorithms, 7, 1994.

  • **** -*** 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 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 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, KSP, KSPFGMRES, KSPBCGS, KSPSetPCSide(), KSPBCGSLSetEll(), KSPBCGSLSetXRes()

Level#

beginner

Location#

src/ksp/ksp/impls/bcgsl/bcgsl.c


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