org.apache.commons.nabla.forward.analysis
Class MethodDifferentiator

java.lang.Object
  org.apache.commons.nabla.forward.analysis.MethodDifferentiator

public class MethodDifferentiator
extends Object

Class transforming a method computing a value to a method computing both a value and its differential.

Version:

$Id$

Constructor Summary

MethodDifferentiator(Set<String> mathClasses, String derivedName)
Build a differentiator for a method.

Method Summary

void	differentiate(String primitiveName, org.objectweb.asm.tree.MethodNode method) Differentiate a method.
org.objectweb.asm.tree.InsnList	doubleToDerivativeStructureConversion() Create instructions to convert a double on top of stack to a DerivativeStructure.
int	getInputDSIndex() Get the index of the input derivative structure variable.
int	getTmp(int number) Get index of a size 2 temporary variable.
boolean	isMathImplementationClass(String name) Test if a class is a math implementation class.
void	useLocal(int index, int size) Set a local variable as used by the modified code.

Methods inherited from class java.lang.Object

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

Constructor Detail

MethodDifferentiator

public MethodDifferentiator(Set<String> mathClasses,
                            String derivedName)

Build a differentiator for a method.

Parameters:

mathClasses - math implementation classes

derivedName - name of the derived class

Method Detail

getInputDSIndex

public int getInputDSIndex()

Get the index of the input derivative structure variable.

Returns:

index of the input derivative structure variable

differentiate

public void differentiate(String primitiveName,
                          org.objectweb.asm.tree.MethodNode method)
                   throws DifferentiationException

Differentiate a method.

Parameters:

primitiveName - primitive class name

method - method to differentiate (will be modified)

Throws:

DifferentiationException - if method cannot be differentiated

isMathImplementationClass

public boolean isMathImplementationClass(String name)

Test if a class is a math implementation class.

Parameters:

name - name of the class to test

Returns:

true if the named class is a math implementation class

doubleToDerivativeStructureConversion

public org.objectweb.asm.tree.InsnList doubleToDerivativeStructureConversion()

Create instructions to convert a double on top of stack to a DerivativeStructure.

Returns:

list of conversion instructions

useLocal

public void useLocal(int index,
                     int size)
              throws DifferentiationException

Set a local variable as used by the modified code.

Parameters:

index - index of the variable

size - size of the variable (1 or 2 for standard variables, 4 for special expanded derivative structures)

Throws:

DifferentiationException - if the number of the temporary variable lies outside of the allowed range

getTmp

public int getTmp(int number)
           throws DifferentiationException

Get index of a size 2 temporary variable.

Temporary variables can be used for very short duration storage of size 2 values (i.e one double, or one long or two integers). These variables are reused in many replacement instructions sequences, so their content may be overridden at any time: they should be considered to have a scope limited to one replacement sequence only. This means that one should not store a value in a variable in one replacement sequence and retrieve it later in another replacement sequence as it may have been overridden in between.

At most 5 temporary variables may be used.

Parameters:

number - number of the temporary variable (must be between 1 and the maximal number of available temporary variables)

Returns:

index of the variable within the local variables array

Throws:

DifferentiationException - if the number of the temporary variable lies outside of the allowed range