com.singularsys.extensions.xjep

Class XJep

java.lang.Object

com.singularsys.jep.Jep

com.singularsys.extensions.xjep.XJep

All Implemented Interfaces:

java.io.Serializable

Direct Known Subclasses:

DJep

public class XJep
extends Jep

An extended version of Jep adds various routines for working with trees. Has a NodeFactory, and OperatorTable, TreeUtils and Visitors DoNothingVisitor,

Author:

Rich Morris Created on 16-Nov-2003

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected ExpressionCleaner	cleaner
protected CommandVisitor	commandv
protected DeepCopyVisitor	copier
protected EquationExtractor	extractor
protected PolynomialCreator	polyv
protected RewriteVisitor	rewritev
protected SubstitutionVisitor	subv
protected TreeUtils	tu A few utility functions.

Fields inherited from class com.singularsys.jep.Jep

additionalComponents, allowAssignment, allowUndeclared, evaluator, funTab, implicitMul, lastRootNode, nodeFac, numFac, opTab, parser, pv, varFac, varTab

Constructor Summary

Constructors

Constructor and Description
XJep() Create a new XJep with all the function of Jep plus simplification and other features.
XJep(ComponentSet components) Create a new XJep instance using specified components set and default components if necessary.
XJep(JepComponent... components) Create a new XJep instance using specified components and default components if necessary.

Method Summary

Modifier and Type	Method and Description
boolean	addRewriteRule(RewriteRuleI rule)
java.lang.Object	calcVarValue(java.lang.String name, boolean force) Calculates the value for the variables equation and returns that value.
Node	clean(Node node) Returns a cleaned up version of an expression tree.
Node	deepCopy(Node node) Returns a deep copy of an expression tree.
boolean	equals(Node lhs, Node rhs) Compare two expressions symbolically.
Node	expand(Node node) Expand brackets in an expression
CommandVisitor	getCommandVisitor()
DeepCopyVisitor	getCopier()
ExpressionCleaner	getExpressionCleaner()
EquationExtractor	getExtractor()
PolynomialCreator	getPolynomialCreator()
RewriteVisitor	getRewriteVisitor()
SubstitutionVisitor	getSubstitutionVisitor()
TreeUtils	getTreeUtils() Returns the TreeUtilitities, used for examining properties of nodes.
java.util.Set<Variable>	getVarsInEquation(Node n) Finds all the variables in an equation.
java.util.Set<Variable>	getVarsInEquation(Node n, java.util.Set<Variable> vars) Finds all the variables in an equation.
Node	preprocess(Node node) Pre-processes an equation to allow the diff and eval operators to be used.
java.util.Set<XVariable>	recursiveGetVarsInEquation(Node n, java.util.Set<XVariable> vars) Finds all the variables in an equation and if any of those variables are defined by equations find the variables in those equations as well.
Node	replaceRHSVariablesByEquations(Node node) Replace variables on the right had side of an assignment by their equations
Node	replaceVariableByExpressions(Node node) Replace all symbolic variable by their equations
Node	rewrite(Node node, boolean clean)
protected void	setXComponentInternal(JepComponent comp)
Node	simplify(Node node) Returns a simplification of an expression tree.
Node	substitute(Node orig, Node sub) Substitute all occurrences of the variable on the left hand side of sub with the expression tree on the right hand side.
Node	substitute(Node orig, Node[] subs) Substitute all occurrences of the variable on the left hand side of sub with the expression tree on the right hand side.
Node	substitute(Node orig, java.lang.String[] names, Node[] replacements) Substitute all occurrences of a set of named variable with a set of expression tree.
Node	substitute(Node orig, java.lang.String[] names, java.lang.Object[] values) Substitute all occurrences of the variable with their values.
Node	substitute(Node orig, java.lang.String name, Node replacement) Substitute all occurrences of a named variable with an expression.
Node	substitute(Node orig, java.lang.String name, java.lang.Object value) Substitute all occurrences of a named variable with a constant value.
Node	substituteConstantVariables(Node orig) Replace all constant variables like pi by their values.

Methods inherited from class com.singularsys.jep.Jep

addConstant, addDefaultComponents, addFunction, addStandardConstants, addVariable, addVariable, addVariable, addVariable, continueParsing, evaluate, evaluate, evaluateD, getAdditionalComponent, getAdditionalComponents, getAllowAssignment, getAllowUndeclared, getDefaultValue, getEvaluator, getFunctionTable, getImplicitMul, getLastRootNode, getNodeFactory, getNumberFactory, getOperatorTable, getParser, getPrintVisitor, getVariable, getVariableFactory, getVariableTable, getVariableValue, initMultiParse, initMultiParse, parse, parse, print, print, print, println, println, println, reinitializeComponents, rootNodeToString, setAllowAssignment, setAllowUndeclared, setComponent, setComponentInternal, setComponents, setComponentsInternal, setDefaultValue, setImplicitMul, setVariable, toString, tryAddConstant

Methods inherited from class java.lang.Object

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

Field Detail

tu

protected TreeUtils tu

A few utility functions.

copier

protected DeepCopyVisitor copier

subv

protected SubstitutionVisitor subv

cleaner

protected ExpressionCleaner cleaner

commandv

protected CommandVisitor commandv

polyv

protected PolynomialCreator polyv

rewritev

protected RewriteVisitor rewritev

extractor

protected EquationExtractor extractor

Constructor Detail

XJep

public XJep()

Create a new XJep with all the function of Jep plus simplification and other features.

XJep

public XJep(JepComponent... components)

Create a new XJep instance using specified components and default components if necessary.

Parameters:

components -

XJep

public XJep(ComponentSet components)

Create a new XJep instance using specified components set and default components if necessary.

Parameters:

components -

Method Detail

setXComponentInternal

protected void setXComponentInternal(JepComponent comp)

preprocess

public Node preprocess(Node node)
                throws ParseException

Pre-processes an equation to allow the diff and eval operators to be used. Uses the CommandVisitor

Throws:

ParseException

deepCopy

public Node deepCopy(Node node)
              throws ParseException

Returns a deep copy of an expression tree.

Throws:

ParseException

See Also:

DeepCopyVisitor

clean

public Node clean(Node node)
           throws ParseException

Returns a cleaned up version of an expression tree. First does a deep copy of the tree.

Throws:

ParseException

See Also:

ExpressionCleaner

simplify

public Node simplify(Node node)
              throws ParseException

Returns a simplification of an expression tree.

Throws:

ParseException

See Also:

PolynomialCreator.simplify(Node)

expand

public Node expand(Node node)
            throws ParseException

Expand brackets in an expression

Parameters:

node - expression to expand

Returns:

expanded version of expression

Throws:

ParseException

See Also:

PolynomialCreator.expand(Node)

equals

public boolean equals(Node lhs,
                      Node rhs)
               throws ParseException

Compare two expressions symbolically.

Parameters:

lhs -

rhs -

Returns:

true if symbolically equal after rearrangement

Throws:

ParseException

See Also:

PolynomialCreator.equals(Node, Node)

substitute

public Node substitute(Node orig,
                       java.lang.String name,
                       java.lang.Object value)
                throws ParseException

Substitute all occurrences of a named variable with a constant value.

Parameters:

orig - expression to substitute into

name - name of variable to substitute

value - its replacement value

Returns:

expression after substitution

Throws:

ParseException

substitute

public Node substitute(Node orig,
                       java.lang.String name,
                       Node replacement)
                throws ParseException

Substitute all occurrences of a named variable with an expression.

Parameters:

orig - expression to substitute into

name - name of variable to substitute

replacement - expression to

Returns:

expression after substitution

Throws:

ParseException

substitute

public Node substitute(Node orig,
                       Node sub)
                throws ParseException

Substitute all occurrences of the variable on the left hand side of sub with the expression tree on the right hand side.

Parameters:

orig - expression to substitute into

sub - expression of the form x=....

Returns:

expression after substitution

Throws:

ParseException

substitute

public Node substitute(Node orig,
                       java.lang.String[] names,
                       java.lang.Object[] values)
                throws ParseException

Substitute all occurrences of the variable with their values.

Throws:

ParseException

substitute

public Node substitute(Node orig,
                       Node[] subs)
                throws ParseException

Substitute all occurrences of the variable on the left hand side of sub with the expression tree on the right hand side.

Throws:

ParseException

substitute

public Node substitute(Node orig,
                       java.lang.String[] names,
                       Node[] replacements)
                throws ParseException

Substitute all occurrences of a set of named variable with a set of expression tree.

Throws:

ParseException

substituteConstantVariables

public Node substituteConstantVariables(Node orig)
                                 throws ParseException

Replace all constant variables like pi by their values.

Parameters:

orig - the input

Returns:

a copy of the input with all constant variables substituted by their values.

Throws:

ParseException

replaceRHSVariablesByEquations

public Node replaceRHSVariablesByEquations(Node node)
                                    throws JepException

Replace variables on the right had side of an assignment by their equations

Parameters:

node - an equation of the form g:=f^2-1

Returns:

a copy of the node

Throws:

JepException

replaceVariableByExpressions

public Node replaceVariableByExpressions(Node node)
                                  throws JepException

Replace all symbolic variable by their equations

Parameters:

node - root of expression

Returns:

copy of node with variables replaced by their equations

Throws:

JepException

calcVarValue

public java.lang.Object calcVarValue(java.lang.String name,
                                     boolean force)
                              throws EvaluationException

Calculates the value for the variables equation and returns that value. If the variable does not have an equation just return its value. Recursively calculates the values of any variable with equations which appear.

Parameters:

name - name of variable

force - whether to force re-evaluation if the variable has a valid value

Returns:

value of variable

Throws:

EvaluationException

getVarsInEquation

public java.util.Set<Variable> getVarsInEquation(Node n)

Finds all the variables in an equation.

Parameters:

n - the top node of the expression

Returns:

v

getVarsInEquation

public java.util.Set<Variable> getVarsInEquation(Node n,
                                                 java.util.Set<Variable> vars)

Finds all the variables in an equation.

Parameters:

n - the top node of the expression

vars - the list of variables (new variables will be added on end)

Returns:

v

recursiveGetVarsInEquation

public java.util.Set<XVariable> recursiveGetVarsInEquation(Node n,
                                                           java.util.Set<XVariable> vars)
                                                    throws ParseException

Finds all the variables in an equation and if any of those variables are defined by equations find the variables in those equations as well. The result is an ordered sequence, evaluating each variable in turn will correctly allow the final equation to be evaluated.

For example if the equation is a+b and a=c+d, b=c+e then the result will be the sequence (c,d,a,e,b) For this method to work the equations must be preprocessed using preprocess(com.singularsys.jep.parser.Node).

Parameters:

n - top node

vars - list of variables, new variables will be added on the end.

Returns:

v, the ordered sequence of variables

Throws:

ParseException - if equation is recursive i.e. x=y; y=x+1;

rewrite

public Node rewrite(Node node,
                    boolean clean)
             throws ParseException

Throws:

ParseException

addRewriteRule

public boolean addRewriteRule(RewriteRuleI rule)

getTreeUtils

public TreeUtils getTreeUtils()

Returns the TreeUtilitities, used for examining properties of nodes.

getCopier

public DeepCopyVisitor getCopier()

getSubstitutionVisitor

public SubstitutionVisitor getSubstitutionVisitor()

getExpressionCleaner

public ExpressionCleaner getExpressionCleaner()

getCommandVisitor

public CommandVisitor getCommandVisitor()

getPolynomialCreator

public PolynomialCreator getPolynomialCreator()

getRewriteVisitor

public RewriteVisitor getRewriteVisitor()

getExtractor

public EquationExtractor getExtractor()