PolynomialCreator

java.lang.Object
- org.lsmp.djep.xjep.DoNothingVisitor
- - org.lsmp.djep.sjep.PolynomialCreator

All Implemented Interfaces:

ParserVisitor
```
public class PolynomialCreator
extends DoNothingVisitor
```
Main entry point for simplification routines.
Uses a complete reworking of the ways equations are represented. A tree structure is built from Polynomials, Monomials, PVariable etc. An equation like
```
1+2 x^2+3 x y+4 x sin(y)
```
is represented as
```
Polynomial([
  Monomial(2.0,[PVariable(x)],[2])]),
  Monomial(3.0,[x,y],[1,1]),
  Monomial(4.0,[x,Function(sin,arg)],[1,1])
])
```
A total ordering of all expressions is used. As the representation is constructed the total ordering of terms is maintained. This helps ensure that polynomials are always in their simplest form and also allows comparison of equations.

The following sequence illustrates current ordering. This ordering may change without warning.
- -1 numbers sorted by values
- 0
- 1 numbers before monomials
- a^-2 powers in increasing order
- a^-1
- a
- a^2
- a^3
- a^x numeric powers before symbolic powers
- a b single variable monomials before multiple variables
- a^2 b
- b variables sorted alphabetically
- cos(a) monomials before functions
- sin(a) function names sorted alphabetically
- a+b functions before polynomials
- a+b+c

Constructor Summary

Constructors
Constructor and Description

PolynomialCreator(XJep j)

Constructors
Constructor and Description
`PolynomialCreator(XJep j)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`int`	`compare(Node node1, Node node2)` Compares two nodes.
`PNodeI`	`createPoly(Node node)` Converts an expression into the polynomial representation.
`boolean`	`equals(Node node1, Node node2)` Compares two nodes.
`Node`	`expand(Node node)` Expands an expression.
`Node`	`simplify(Node node)` Simplifies an expression.
`Object`	`visit(ASTConstant node, Object data)`
`Object`	`visit(ASTFunNode node, Object data)`
`Object`	`visit(ASTVarNode node, Object data)`

Methods inherited from class org.lsmp.djep.xjep.DoNothingVisitor
visit, visit

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - PolynomialCreator
```
public PolynomialCreator(XJep j)
```
- Method Detail
  - createPoly
```
public PNodeI createPoly(Node node)
                  throws ParseException
```
    Converts an expression into the polynomial representation.
    
    Parameters:
    
    node - top node of expression
    
    Returns:
    
    top node of polynomial form of expression
    
    Throws:
    
    ParseException - if expression cannot be converted.
  - simplify
```
public Node simplify(Node node)
              throws ParseException
```
    Simplifies an expression.
    
    Parameters:
    
    node - top node to expression to be simplified.
    
    Returns:
    
    a simplified expression
    
    Throws:
    
    ParseException
  - expand
```
public Node expand(Node node)
            throws ParseException
```
    Expands an expression. Will always expand brackets for multiplication and simple powers. For instance (1+x)^3 -> 1+3x+3x^2+x^3
    
    Parameters:
    
    node - top node to expression to be simplified.
    
    Returns:
    
    a simplified expression
    
    Throws:
    
    ParseException
  - compare
```
public int compare(Node node1,
                   Node node2)
            throws ParseException
```
    Compares two nodes. Uses a total ordering of expressions. Expands equations before comparison.
    
    Parameters:
    
    node1 -
    
    node2 -
    
    Returns:
    
    -1 if node1node2
    
    Throws:
    
    ParseException
  - equals
```
public boolean equals(Node node1,
                      Node node2)
               throws ParseException
```
    Compares two nodes. Uses a total ordering of expressions. May give some false negatives is simplification cannot reduce two equal expressions to the same canonical form. Expands equations before comparison.
    
    Parameters:
    
    node1 -
    
    node2 -
    
    Returns:
    
    true if two nodes represents same expression.
    
    Throws:
    
    ParseException
  - visit
```
public Object visit(ASTConstant node,
                    Object data)
             throws ParseException
```
    Specified by:
    
    visit in interface ParserVisitor
    
    Overrides:
    
    visit in class DoNothingVisitor
    
    Throws:
    
    ParseException
  - visit
```
public Object visit(ASTVarNode node,
                    Object data)
             throws ParseException
```
    Specified by:
    
    visit in interface ParserVisitor
    
    Overrides:
    
    visit in class DoNothingVisitor
    
    Throws:
    
    ParseException
  - visit
```
public Object visit(ASTFunNode node,
                    Object data)
             throws ParseException
```
    Specified by:
    
    visit in interface ParserVisitor
    
    Overrides:
    
    visit in class DoNothingVisitor
    
    Throws:
    
    ParseException

Class PolynomialCreator

Constructor Summary

Method Summary

Methods inherited from class org.lsmp.djep.xjep.DoNothingVisitor

Methods inherited from class java.lang.Object

Constructor Detail

PolynomialCreator

Method Detail

createPoly

simplify

expand

compare

equals

visit

visit

visit