com.singularsys.extensions.djep.diffRules

Class ChainRuleDiffRules

java.lang.Object

com.singularsys.extensions.djep.diffRules.ChainRuleDiffRules

All Implemented Interfaces:

DiffRulesI, JepComponent, java.io.Serializable

Direct Known Subclasses:

MacroDiffRules, MacroFunctionDiffRules

public abstract class ChainRuleDiffRules
extends java.lang.Object
implements DiffRulesI

Abstract base class for function which are differentiated using the chain rule. All subclasses should specify the name pfmc rules and descriptions fields. The rules specify the derivative of the function wrt i-th argument which is supplied as a Node Variable names in rules MUST be x,y for 1 to 2 variables. So for the function f(x,y) with two arguments if rules representing df/dx and df/dy are specified and x and y are functions of a further variable z then the derivative wrt z is found using the chain rule df(x,y)/dz -> df/dx * dx/dz + df/dy * dy/dz.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected DeepCopyVisitor	copier
protected DifferentiationVisitor	dv
protected NodeFactory	nf
protected OperatorTableI	opSet
protected SubstitutionVisitor	subv

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ChainRuleDiffRules(DJep djep) Constructor.

Method Summary

Modifier and Type	Method and Description
Node	differentiate(ASTFunNode node, java.lang.String var, Node[] children, Node[] dchildren) Use the chain rule to differentiate.
java.lang.String[]	getArgNames()
java.lang.String[]	getDescriptions()
JepComponent	getLightWeightInstance() Gets a light-weight instance suitable for using in multiple threads.
java.lang.String	getName() returns the name of the function
int	getNumRules() Returns the number of rules which should be number of arguments of function
PostfixMathCommandI	getPfmc() returns the PostfixMathCommandI for the function.
Node	getRule(int i) returns the i-th rule as an expression tree.
void	init(Jep djep) Initialize the component.
protected void	setup(java.lang.String funName, PostfixMathCommandI pfmc, Node[] rules, java.lang.String[] descriptions, java.lang.String[] argNames) Set the internal variables for function with multiple arguments
protected void	setup(java.lang.String funName, PostfixMathCommandI pfmc, Node rule1, Node rule2, java.lang.String description1, java.lang.String description2) Set the internal variables for binary function with arguments named 'x' 'y'
protected void	setup(java.lang.String funName, PostfixMathCommandI pfmc, Node rule, java.lang.String description) Set the internal variables for unary function with argument named 'x'
java.lang.String	toString() Returns a string representation of the rule.

Methods inherited from class java.lang.Object

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

Field Detail

dv

protected DifferentiationVisitor dv

opSet

protected OperatorTableI opSet

nf

protected NodeFactory nf

copier

protected DeepCopyVisitor copier

subv

protected SubstitutionVisitor subv

Constructor Detail

ChainRuleDiffRules

protected ChainRuleDiffRules(DJep djep)

Constructor. Sub class should call a setup method to complete construction.

Method Detail

setup

protected void setup(java.lang.String funName,
                     PostfixMathCommandI pfmc,
                     Node rule,
                     java.lang.String description)

Set the internal variables for unary function with argument named 'x'

Parameters:

funName - name of function

pfmc - Jep function

rule - expression for derivative wrt 'x'

description - string rep of derivative

setup

protected void setup(java.lang.String funName,
                     PostfixMathCommandI pfmc,
                     Node rule1,
                     Node rule2,
                     java.lang.String description1,
                     java.lang.String description2)

Set the internal variables for binary function with arguments named 'x' 'y'

Parameters:

funName - name of function

pfmc - Jep function

rule1 - expression for derivative wrt 'x'

rule2 - expression for derivative wrt 'y'

description1 - string rep of derivative

description2 - string rep of derivative

setup

protected void setup(java.lang.String funName,
                     PostfixMathCommandI pfmc,
                     Node[] rules,
                     java.lang.String[] descriptions,
                     java.lang.String[] argNames)

Set the internal variables for function with multiple arguments

Parameters:

funName - name of function

pfmc - Jep function

rules - expression for derivatives

descriptions - text rep of derivatives

argNames - names of the variables of the function

differentiate

public Node differentiate(ASTFunNode node,
                          java.lang.String var,
                          Node[] children,
                          Node[] dchildren)
                   throws JepException

Use the chain rule to differentiate. diff(f(g(x),h(x)),x) -> df/dg * dg/dx + df/dh * dh/dx

Specified by:

differentiate in interface DiffRulesI

var - The name of variable to differentiate wrt to.

children - the arguments of the function

dchildren - the derivatives of each argument of the function.

Returns:

top node of and expression tree for the derivative.

Throws:

JepException

ParseException - if there is some problem in compiling the derivative.

init

public void init(Jep djep)

Description copied from interface: JepComponent

Initialize the component. This methods is called whenever a component is added to Jep. Hence it allows components to keep track of the other components they may rely on.

Specified by:

init in interface JepComponent

Parameters:

djep - the current Jep instance

getLightWeightInstance

public JepComponent getLightWeightInstance()

Description copied from interface: JepComponent

Gets a light-weight instance suitable for using in multiple threads.

Specified by:

getLightWeightInstance in interface JepComponent

Returns:

either an new instance, or 'this'.

getName

public java.lang.String getName()

returns the name of the function

Specified by:

getName in interface DiffRulesI

getPfmc

public PostfixMathCommandI getPfmc()

returns the PostfixMathCommandI for the function.

getNumRules

public int getNumRules()

Returns the number of rules which should be number of arguments of function

getRule

public Node getRule(int i)

returns the i-th rule as an expression tree.

getDescriptions

public java.lang.String[] getDescriptions()

getArgNames

public java.lang.String[] getArgNames()

toString

public java.lang.String toString()

Description copied from interface: DiffRulesI

Returns a string representation of the rule.

Specified by:

toString in interface DiffRulesI

Overrides:

toString in class java.lang.Object