org.hipparchus.optim.nonlinear.scalar

Class LineSearch

java.lang.Object

org.hipparchus.optim.nonlinear.scalar.LineSearch

public class LineSearch
extends Object

Class for finding the minimum of the objective function along a given direction.

Constructor Summary

Constructors

Constructor and Description
LineSearch(MultivariateOptimizer optimizer, double relativeTolerance, double absoluteTolerance, double initialBracketingRange) The BrentOptimizer default stopping criterion uses the tolerances to check the domain (point) values, not the function values.

Method Summary

Modifier and Type	Method and Description
UnivariatePointValuePair	search(double[] startPoint, double[] direction) Finds the number alpha that optimizes f(startPoint + alpha * direction).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LineSearch

public LineSearch(MultivariateOptimizer optimizer,
                  double relativeTolerance,
                  double absoluteTolerance,
                  double initialBracketingRange)

The BrentOptimizer default stopping criterion uses the tolerances to check the domain (point) values, not the function values. The relativeTolerance and absoluteTolerance arguments are thus passed to a custom checker that will use the function values.

Parameters:

optimizer - Optimizer on behalf of which the line search be performed. Its computeObjectiveValue method will be called by the search method.

relativeTolerance - Search will stop when the function relative difference between successive iterations is below this value.

absoluteTolerance - Search will stop when the function absolute difference between successive iterations is below this value.

initialBracketingRange - Extent of the initial interval used to find an interval that brackets the optimum. If the optimized function varies a lot in the vicinity of the optimum, it may be necessary to provide a value lower than the distance between successive local minima.

Method Detail

search

public UnivariatePointValuePair search(double[] startPoint,
                                       double[] direction)

Finds the number alpha that optimizes f(startPoint + alpha * direction).

Parameters:

startPoint - Starting point.

direction - Search direction.

Returns:

the optimum.

Throws:

MathIllegalStateException - if the number of evaluations is exceeded.