SNESLINESEARCHCP

Critical point line search. This line search assumes that there exists some artificial \(G(x)\) for which the SNESFunctionFn \(F(x) = grad G(x)\). Therefore, this line search seeks to find roots of the directional derivative via a secant method, that is \(F(x_k - \lambda Y_k) \cdot Y_k / ||Y_k|| = 0\).

Options Database Keys

• -snes_linesearch_minlambda 1e-12 - the minimum acceptable lambda (scaling of solution update)

• -snes_linesearch_maxlambda 1.0 - the algorithm ensures that lambda is never larger than this value

• -snes_linesearch_damping 1.0 - initial lambda on entry to the line search

• -snes_linesearch_order 1 - order of the approximation in the secant method, must be 1, 2, or 3

• -snes_linesearch_max_it 1 - the maximum number of secant iterations performed

• -snes_linesearch_rtol 1e-8 - relative tolerance for the directional derivative

• -snes_linesearch_atol 1e-15 - absolute tolerance for the directional derivative

• -snes_linesearch_ltol 1e-8 - minimum absolute change in lambda allowed

Notes

This method does NOT use the objective function if it is provided with SNESSetObjective().

This method is the preferred line search for SNESQN and SNESNCG.

See Also

SNES: Nonlinear Solvers, SNESLineSearch, SNESLineSearchType, SNESLineSearchCreate(), SNESLineSearchSetType(), SNESLINESEARCHBISECTION

Level

advanced

Location

src/snes/linesearch/impls/cp/linesearchcp.c

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Index of all SNES routines
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