de.torstennahm.integrate.quadratureformula
Class AbstractCachedGenerator

java.lang.Object
  de.torstennahm.integrate.quadratureformula.AbstractCachedGenerator

All Implemented Interfaces:

Generator

Direct Known Subclasses:

ClenshawCurtis, DeltaGenerator, GaussHermite, GaussianWrapper, GaussLegendre, OpenTrapezoidal, Patterson, Trapezoidal

public abstract class AbstractCachedGenerator
extends java.lang.Object
implements Generator

Provides functionality for caching and retrieving quadrature formulas.

Since quadrature formulas are immutable, they can be returned from a cache and need only be calculated once.

According to general Generator contract, this class is thread-safe.

Author:

Torsten Nahm

Field Summary

protected java.util.Map<java.lang.Integer,QuadratureFormula>	levelCache
protected java.util.Map<java.lang.Integer,QuadratureFormula>	weightsCache

Constructor Summary

AbstractCachedGenerator()

Method Summary

protected abstract QuadratureFormula	generateByLevel(int level)
protected abstract QuadratureFormula	generateByNodes(int nodesRequested)
QuadratureFormula	getByLevel(int level) This routine is similar to getByLevel, but here the argument is only an abstract measure of the number of node-and-weight-pairs returned.
QuadratureFormula	getByNodes(int nodesRequested) Returns a set of node-and-weight pairs in an QuadratureFormula object.

Methods inherited from class java.lang.Object

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

Methods inherited from interface de.torstennahm.integrate.quadratureformula.Generator

maxLevel, maxNodes

Field Detail

weightsCache

protected java.util.Map<java.lang.Integer,QuadratureFormula> weightsCache

levelCache

protected java.util.Map<java.lang.Integer,QuadratureFormula> levelCache

Constructor Detail

AbstractCachedGenerator

public AbstractCachedGenerator()

Method Detail

generateByNodes

protected abstract QuadratureFormula generateByNodes(int nodesRequested)

generateByLevel

protected abstract QuadratureFormula generateByLevel(int level)

getByNodes

public QuadratureFormula getByNodes(int nodesRequested)

Description copied from interface: Generator

Returns a set of node-and-weight pairs in an QuadratureFormula object. The number of nodes returned should be the same as those requested. If this is not possible due to the special structure of the generator, the number of nodes returned must be larger than that requested. However, when 1 node is requested exactly 1 pair must be returned.

The number of nodes requested must be between 1 and getMaxNodes().

Specified by:

getByNodes in interface Generator

Parameters:

nodesRequested - number of nodes for the quadrature formula

Returns:

quadrature formula

getByLevel

public QuadratureFormula getByLevel(int level)

Description copied from interface: Generator

This routine is similar to getByLevel, but here the argument is only an abstract measure of the number of node-and-weight-pairs returned. In general, the number of weights should rise exponentially with the level. However, the only conditions imposed it that the number of pairs should rise strictly monotonously with the level. level must be between 0 and getMaxLevel().

In the special case where level is requested as 0, a quadrature formula with exactly 1 pair must be returned.

Specified by:

getByLevel in interface Generator

Parameters:

level - level of the quadrature formula

Returns:

quadrature formula