petsc-3.12.5 2020-03-29

SNESNCG

Nonlinear Conjugate-Gradient method for the solution of general nonlinear systems.

Options Database

	-snes_ncg_type <fr, prp, dy, hs, cd>	- Choice of conjugate-gradient update parameter, default is prp.
	-snes_linesearch_type <cp,l2,basic>	- Line search type.
	-snes_ncg_monitor	- Print the beta values used in the ncg iteration, .

Notes

This solves the nonlinear system of equations F(x) = 0 using the nonlinear generalization of the conjugate gradient method. This may be used with a nonlinear preconditioner used to pick the new search directions, but otherwise chooses the initial search direction as F(x) for the initial guess x.

Only supports left non-linear preconditioning.

Default line search is SNESLINESEARCHCP, unless a nonlinear preconditioner is used with -npc_snes_type <type>, SNESSetNPC(), or SNESGetNPC() then SNESLINESEARCHL2 is used. Also supports the special purpose line search SNESLINESEARCHNCGLINEAR

References

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

Level

beginner

Location