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NOX::LineSearch::Generic Class Referenceabstract

Base class line search interface. More...

#include <NOX_LineSearch_Generic.H>

Inheritance diagram for NOX::LineSearch::Generic:
Inheritance graph

Public Member Functions

 Generic ()
 Default constructor.
virtual ~Generic ()
virtual bool compute (NOX::Abstract::Group &grp, double &step, const NOX::Abstract::Vector &dir, const NOX::Solver::Generic &s)=0
 Perform a line search. More...

Detailed Description

Base class line search interface.

Every line search should respect the following Parameter:

Member Function Documentation

virtual bool NOX::LineSearch::Generic::compute ( NOX::Abstract::Group grp,
double &  step,
const NOX::Abstract::Vector dir,
const NOX::Solver::Generic s 
pure virtual

Perform a line search.

On input:

grpThe initial solution vector, $x_{\rm old}$.
dirA vector of directions to be used in the line search, $d$.
sThe nonlinear solver.

On output:

stepThe distance the direction was scaled, $ \lambda $.
grpThe grp is updated with a new solution, $ x_{\rm new} $, resulting from the linesearch. Normally, for a single direction line search, this is computed as:

\[ x_{\rm new} = x_{\rm old} + \lambda d. \]

Ideally, $ \|F(x_{\rm new})\| < \|F(x_{\rm old})\| $ (e.g the final direction is a descent direction).

Note that the dir object is a std::vector. For typical line searches as described in the above equation, this vector is of size one. We have used a std::vector to allow for special cases of multi-directional line searches such as the Bader/Schnabel curvillinear line search.

Return value is true for a successful line search computation.

Implemented in NOX::LineSearch::Polynomial, NOX::LineSearch::MoreThuente, NOX::LineSearch::NonlinearCG, NOX::LineSearch::Backtrack, NOX::LineSearch::SafeguardedStep, NOX::LineSearch::SafeguardedDirection, and NOX::LineSearch::FullStep.

The documentation for this class was generated from the following file: