org.lsmp.djep.djep.diffRules

Class ChainRuleDiffRules

java.lang.Object

org.lsmp.djep.djep.diffRules.ChainRuleDiffRules

All Implemented Interfaces:

DiffRulesI

Direct Known Subclasses:

MacroDiffRules, MacroFunctionDiffRules

public abstract class ChainRuleDiffRules
extends Object
implements DiffRulesI

Common methods used when the rules are specified by node trees or strings. All subclasses use the chain rule to differentiate. df(g(x),h(x))/dx -> df/dg * dg/dx + df/dh * dh/dx Variable names MUST be x,y for 1 to 2 variables or x1,x2,x3 for 3 for more variables.

Field Summary

Fields

Modifier and Type	Field and Description
protected String	name
protected PostfixMathCommandI	pfmc
protected Node[]	rules

Constructor Summary

Constructors

Constructor and Description
ChainRuleDiffRules() Cannot construct outside the context of a differentation visitor.

Method Summary

Modifier and Type	Method and Description
Node	differentiate(ASTFunNode node, String var, Node[] children, Node[] dchildren, DJep djep) Use the chain rule to differentiate.
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.
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

name

protected String name

pfmc

protected PostfixMathCommandI pfmc

rules

protected Node[] rules

Constructor Detail

ChainRuleDiffRules

public ChainRuleDiffRules()

Cannot construct outside the context of a differentation visitor.

Method Detail

getName

public 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.

differentiate

public Node differentiate(ASTFunNode node,
                          String var,
                          Node[] children,
                          Node[] dchildren,
                          DJep djep)
                   throws ParseException

Use the chain rule to differentiate. df(g(x),h(x))/dx -> 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:

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

toString

public String toString()

Description copied from interface: DiffRulesI

Returns a string representation of the rule.

Specified by:

toString in interface DiffRulesI

Overrides:

toString in class Object