petsc-3.9.4 2018-09-11
Report Typos and Errors

SNESLINESEARCHBASIC

 This line search implementation is not a line search at all; it simply uses the full step. Thus, this routine is intended for methods with well-scaled updates; i.e. Newton's method (SNESNEWTONLS), on well-behaved problems.

Options Database Keys

-snes_linesearch_damping <damping> - search vector is scaled by this amount, default is 1.0
-snes_linesearch_norms <flag> - whether to compute norms or not, default is true (SNESLineSearchSetComputeNorms())

Notes

For methods with ill-scaled updates (SNESNRICHARDSON, SNESNCG), a small damping parameter may yield satisfactory but slow convergence despite the simplicity of the line search.

Keywords

SNES, SNESLineSearch, damping

See Also

SNESLineSearchCreate(), SNESLineSearchSetType(), SNESLineSearchSetDamping(), SNESLineSearchSetComputeNorms()

Level

advanced

Location

src/snes/linesearch/impls/basic/linesearchbasic.c

Examples

src/ts/examples/tutorials/ex22.c.html
src/ts/examples/tutorials/ex22f.F.html

Index of all SNES routines
Table of Contents for all manual pages
Index of all manual pages