org.apache.commons.nabla.algorithmic.forward.instructions
Class WideningTransformer

java.lang.Object
  org.apache.commons.nabla.algorithmic.forward.instructions.WideningTransformer

All Implemented Interfaces:

InstructionsTransformer

public class WideningTransformer
extends Object
implements InstructionsTransformer

Differentiation transformer for promoting a double on the stack to a differential pair.

Some instructions pushing a double on the stack simply need to be completed by pushing a 0 afterwards to form a differential pair representing a constant value. These instructions are replaced by a copy of themselves followed by a DCONST_0 instruction.

Method Summary

static InstructionsTransformer	getInstance() Get the singleton instance.
org.objectweb.asm.tree.InsnList	getReplacement(org.objectweb.asm.tree.AbstractInsnNode insn, MethodDifferentiator methodDifferentiator) Get the replacement instructions.

Methods inherited from class java.lang.Object

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

Method Detail

getInstance

public static InstructionsTransformer getInstance()

Get the singleton instance.

We use here the Initialization on Demand Holder idiom.

Returns:

the singleton instance

getReplacement

public org.objectweb.asm.tree.InsnList getReplacement(org.objectweb.asm.tree.AbstractInsnNode insn,
                                                      MethodDifferentiator methodDifferentiator)
                                               throws DifferentiationException

Get the replacement instructions.

Specified by:

getReplacement in interface InstructionsTransformer

Parameters:

insn - original instruction

methodDifferentiator - method differentiator driving this transformer

Returns:

replacement instructions

Throws:

DifferentiationException - if the method differentiator cannot provide a temporary variable