petsc-3.7.1 2016-05-15
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SNESFAS

Full Approximation Scheme nonlinear multigrid solver. The nonlinear problem is solved by correction using coarse versions Many brof the nonlinear problem. This problem is perturbed so that a projected Many brsolution of the fine problem elicits no correction from the coarse problem. Many br

Options Database

-snes_fas_levels - The number of levels Many br
-snes_fas_cycles<1> - The number of cycles -- 1 for V, 2 for W Many br
-snes_fas_type<additive,multiplicative,full,kaskade> - Additive or multiplicative cycle Many br
-snes_fas_galerkin<PETSC_FALSE> - Form coarse problems by projection back upon the fine problem Many br
-snes_fas_smoothup<1> - The number of iterations of the post-smoother Many br
-snes_fas_smoothdown<1> - The number of iterations of the pre-smoother Many br
-snes_fas_monitor - Monitor progress of all of the levels Many br
-snes_fas_full_downsweep<PETSC_FALSE> - call the downsmooth on the initial downsweep of full FAS Many br
-fas_levels_snes_ - SNES options for all smoothers Many br
-fas_levels_cycle_snes_ - SNES options for all cycles Many br
-fas_levels_i_snes_ - SNES options for the smoothers on level i Many br
-fas_levels_i_cycle_snes_ - SNES options for the cycle on level i Many br
-fas_coarse_snes_ - SNES options for the coarsest smoother Many br

Notes

The organization of the FAS solver is slightly different from the organization of PCMG Many brAs each level has smoother SNES instances(down and potentially up) and a cycle SNES instance. Many brThe cycle SNES instance may be used for monitoring convergence on a particular level. Many br

Many br

References

1. -Peter R. Brune, Matthew G. Knepley, Barry F. Smith, and Xuemin Tu, "Composing Scalable Nonlinear Algebraic Solvers", Many brSIAM Review, 57(4), 2015 Many br

See Also

PCMG, SNESCreate(), SNES, SNESSetType(), SNESType (for list of available types)

Level:beginner
Location:
src/snes/impls/fas/fas.c
Index of all SNES routines
Table of Contents for all manual pages
Index of all manual pages

Examples

src/snes/examples/tutorials/ex12.c.html