SNESLINESEARCHBISECTION — PETSc 3.23.0 documentation

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# SNESLINESEARCHBISECTION

Bisection line search. Similar to the critical point line search, `SNESLINESEARCHCP`, the bisection line search assumes that there exists some \(G(x)\) for which the `SNESFunctionFn` \(F(x) = grad G(x)\). This line search seeks to find the root of the directional derivative along the search direction \(F^T Y\) through bisection.

## Options Database Keys

- -snes_linesearch_max_it <50> - maximum number of iterations for the line search

- -snes_linesearch_damping <1.0> - initial trial step length on entry to the line search

- -snes_linesearch_rtol <1e-8> - relative tolerance for the directional derivative

- -snes_linesearch_atol <1e-6> - absolute tolerance for the directional derivative

- -snes_linesearch_ltol <1e-6> - minimum absolute change in lambda allowed

## Note

This method does NOT use the objective function if it is provided with `SNESSetObjective()`. This line search will always give a step size in the interval [0, damping].

## See Also

SNES: Nonlinear Solvers, `SNESLineSearch`, `SNESLineSearchType`, `SNESLineSearchCreate()`, `SNESLineSearchSetType()`, `SNESLINESEARCHCP`

## Level

intermediate

## Location

src/snes/linesearch/impls/bisection/linesearchbisection.c

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