KSPFCG#

Implements the Flexible Conjugate Gradient method (FCG). Unlike most KSP methods this allows the preconditioner to be nonlinear. Flexible Krylov Methods

Options Database Keys#

  • -ksp_fcg_mmax - maximum number of search directions

  • -ksp_fcg_nprealloc - number of directions to preallocate

  • -ksp_fcg_truncation_type <standard,notay> - truncation approach for directions

Note#

Supports left preconditioning only.

Contributed by#

Patrick Sanan

References#

  • **** -*** Notay, Y.”Flexible Conjugate Gradients”, SIAM J. Sci. Comput. 22:4, 2000

  • **** -*** Axelsson, O. and Vassilevski, P. S. “A Black Box Generalized Conjugate Gradient Solver with Inner Iterations and Variable step Preconditioning”, SIAM J. Matrix Anal. Appl. 12:4, 1991

See Also#

KSP: Linear System Solvers, Flexible Krylov Methods, KSPGCR, KSPFGMRES, KSPCG, KSPFCGSetMmax(), KSPFCGGetMmax(), KSPFCGSetNprealloc(), KSPFCGGetNprealloc(), KSPFCGSetTruncationType(), KSPFCGGetTruncationType(), KSPFCGGetTruncationType

Level#

beginner

Location#

src/ksp/ksp/impls/fcg/fcg.c

Examples#

src/ksp/ksp/tutorials/ex7.c

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