org.apache.commons.nabla.forward
Class ForwardModeDifferentiator

java.lang.Object
  org.apache.commons.nabla.forward.ForwardModeDifferentiator

All Implemented Interfaces:

org.apache.commons.math3.analysis.differentiation.UnivariateFunctionDifferentiator

public class ForwardModeDifferentiator
extends Object
implements org.apache.commons.math3.analysis.differentiation.UnivariateFunctionDifferentiator

Algorithmic differentiator class in forward mode based on bytecode analysis.

This class is an implementation of the UnivariateFunctionDifferentiator interface that computes exact differentials completely automatically and generate java classes and instances that compute the differential of the function as if they were hand-coded and compiled.

The derivative bytecode created the first time an instance of a given class is differentiated is cached and will be reused if other instances of the same class are to be created later. The cache can also be dumped in a jar file for use in an application without bringing the full nabla library and its dependencies.

This differentiator can handle only pure bytecode methods and known methods from math implementation classes like Math, StrictMath or FastMath. Pure bytecode methods are analyzed and converted. Methods from math implementation classes are only recognized by class and name and replaced by predefined derivative code.

Version:

$Id$

See Also:

FetchDifferentiator

Constructor Summary

ForwardModeDifferentiator()
Simple constructor.

Method Summary

void	addMathImplementation(Class<?> mathClass) Add an implementation class for mathematical functions.
org.apache.commons.math3.analysis.differentiation.UnivariateDifferentiableFunction	differentiate(org.apache.commons.math3.analysis.UnivariateFunction d)
void	dumpCache(OutputStream out) Dump the cache into a stream.

Methods inherited from class java.lang.Object

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

Constructor Detail

ForwardModeDifferentiator

public ForwardModeDifferentiator()

Simple constructor.

Build a ForwardAlgorithmicDifferentiator instance with an empty cache.

Method Detail

addMathImplementation

public void addMathImplementation(Class<?> mathClass)

Add an implementation class for mathematical functions.

At construction, the differentiator considers only the Math and StrictMath classes are math implementation classes. It may be useful to add other classes for example to add some missing functions like inverse hyperbolic cosine that are not provided by the standard java classes as of Java 1.6.

Parameters:

mathClass - implementation class for mathematical functions

dumpCache

public void dumpCache(OutputStream out)

Dump the cache into a stream.

Parameters:

out - output stream where to dump the cache

differentiate

public org.apache.commons.math3.analysis.differentiation.UnivariateDifferentiableFunction differentiate(org.apache.commons.math3.analysis.UnivariateFunction d)

Specified by:

differentiate in interface org.apache.commons.math3.analysis.differentiation.UnivariateFunctionDifferentiator