org.apache.commons.math.optimization.general

Enum ConjugateGradientFormula

java.lang.Object

java.lang.Enum<ConjugateGradientFormula>

org.apache.commons.math.optimization.general.ConjugateGradientFormula

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<ConjugateGradientFormula>

public enum ConjugateGradientFormula
extends java.lang.Enum<ConjugateGradientFormula>

Available choices of update formulas for the β parameter in NonLinearConjugateGradientOptimizer.

The β parameter is used to compute the successive conjugate search directions. For non-linear conjugate gradients, there are two formulas to compute β:

• Fletcher-Reeves formula
• Polak-Ribière formula

On the one hand, the Fletcher-Reeves formula is guaranteed to converge if the start point is close enough of the optimum whether the Polak-Ribière formula may not converge in rare cases. On the other hand, the Polak-Ribière formula is often faster when it does converge. Polak-Ribière is often used.

Since:

2.0

See Also:

NonLinearConjugateGradientOptimizer

Enum Constant Summary

Enum Constants

Enum Constant and Description
FLETCHER_REEVES Fletcher-Reeves formula.
POLAK_RIBIERE Polak-Ribière formula.

Method Summary

Modifier and Type	Method and Description
static ConjugateGradientFormula	valueOf(java.lang.String name) Returns the enum constant of this type with the specified name.
static ConjugateGradientFormula[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

compareTo, equals, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

FLETCHER_REEVES

public static final ConjugateGradientFormula FLETCHER_REEVES

Fletcher-Reeves formula.

POLAK_RIBIERE

public static final ConjugateGradientFormula POLAK_RIBIERE

Polak-Ribière formula.

Method Detail

values

public static ConjugateGradientFormula[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (ConjugateGradientFormula c : ConjugateGradientFormula.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static ConjugateGradientFormula valueOf(java.lang.String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

java.lang.IllegalArgumentException - if this enum type has no constant with the specified name

java.lang.NullPointerException - if the argument is null