Package org.hipparchus.optim.nonlinear.scalar.noderiv

Class PowellOptimizer

java.lang.Object

org.hipparchus.optim.BaseOptimizer<P>

org.hipparchus.optim.BaseMultivariateOptimizer<PointValuePair>

org.hipparchus.optim.nonlinear.scalar.MultivariateOptimizer

org.hipparchus.optim.nonlinear.scalar.noderiv.PowellOptimizer

public class PowellOptimizer
extends MultivariateOptimizer

Powell's algorithm. This code is translated and adapted from the Python version of this algorithm (as implemented in module optimize.py v0.5 of SciPy).
The default stopping criterion is based on the differences of the function value between two successive iterations. It is however possible to define a custom convergence checker that might terminate the algorithm earlier.
Line search is performed by the LineSearch class.
Constraints are not supported: the call to optimize will throw MathRuntimeException if bounds are passed to it. In order to impose simple constraints, the objective function must be wrapped in an adapter like MultivariateFunctionMappingAdapter or MultivariateFunctionPenaltyAdapter.

Field Summary

Fields inherited from class org.hipparchus.optim.BaseOptimizer

evaluations, iterations

Constructor Summary

Constructors

Constructor	Description
PowellOptimizer(double rel, double abs)	The parameters control the default convergence checking procedure.
PowellOptimizer(double rel, double abs, double lineRel, double lineAbs)	Builds an instance with the default convergence checking procedure.
PowellOptimizer(double rel, double abs, double lineRel, double lineAbs, ConvergenceChecker<PointValuePair> checker)	This constructor allows to specify a user-defined convergence checker, in addition to the parameters that control the default convergence checking procedure and the line search tolerances.
PowellOptimizer(double rel, double abs, ConvergenceChecker<PointValuePair> checker)	This constructor allows to specify a user-defined convergence checker, in addition to the parameters that control the default convergence checking procedure.

Method Summary

Modifier and Type	Method	Description
protected PointValuePair	doOptimize()	Performs the bulk of the optimization algorithm.

Methods inherited from class org.hipparchus.optim.nonlinear.scalar.MultivariateOptimizer

computeObjectiveValue, getGoalType, optimize, parseOptimizationData

Methods inherited from class org.hipparchus.optim.BaseMultivariateOptimizer

getLowerBound, getStartPoint, getUpperBound

Methods inherited from class org.hipparchus.optim.BaseOptimizer

getConvergenceChecker, getEvaluations, getIterations, getMaxEvaluations, getMaxIterations, incrementEvaluationCount, incrementIterationCount, optimize

Methods inherited from class java.lang.Object

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

Constructor Detail

PowellOptimizer

public PowellOptimizer(double rel,
                       double abs,
                       ConvergenceChecker<PointValuePair> checker)

This constructor allows to specify a user-defined convergence checker, in addition to the parameters that control the default convergence checking procedure.
The internal line search tolerances are set to the square-root of their corresponding value in the multivariate optimizer.

Parameters:

rel - Relative threshold.

abs - Absolute threshold.

checker - Convergence checker.

Throws:

MathIllegalArgumentException - if abs <= 0.

MathIllegalArgumentException - if rel < 2 * Math.ulp(1d).

PowellOptimizer

public PowellOptimizer(double rel,
                       double abs,
                       double lineRel,
                       double lineAbs,
                       ConvergenceChecker<PointValuePair> checker)

This constructor allows to specify a user-defined convergence checker, in addition to the parameters that control the default convergence checking procedure and the line search tolerances.

Parameters:

rel - Relative threshold for this optimizer.

abs - Absolute threshold for this optimizer.

lineRel - Relative threshold for the internal line search optimizer.

lineAbs - Absolute threshold for the internal line search optimizer.

checker - Convergence checker.

Throws:

MathIllegalArgumentException - if abs <= 0.

MathIllegalArgumentException - if rel < 2 * Math.ulp(1d).

PowellOptimizer

public PowellOptimizer(double rel,
                       double abs)

The parameters control the default convergence checking procedure.
The internal line search tolerances are set to the square-root of their corresponding value in the multivariate optimizer.

Parameters:

rel - Relative threshold.

abs - Absolute threshold.

Throws:

MathIllegalArgumentException - if abs <= 0.

MathIllegalArgumentException - if rel < 2 * Math.ulp(1d).

PowellOptimizer

public PowellOptimizer(double rel,
                       double abs,
                       double lineRel,
                       double lineAbs)

Builds an instance with the default convergence checking procedure.

Parameters:

rel - Relative threshold.

abs - Absolute threshold.

lineRel - Relative threshold for the internal line search optimizer.

lineAbs - Absolute threshold for the internal line search optimizer.

Throws:

MathIllegalArgumentException - if abs <= 0.

MathIllegalArgumentException - if rel < 2 * Math.ulp(1d).

Method Detail

doOptimize

protected PointValuePair doOptimize()

Performs the bulk of the optimization algorithm.

Specified by:

doOptimize in class BaseOptimizer<PointValuePair>

Returns:

the point/value pair giving the optimal value of the objective function.