org.lsmp.djep.xjep.function

Class SumType

java.lang.Object

org.nfunk.jep.function.PostfixMathCommand

org.lsmp.djep.xjep.function.SumType

All Implemented Interfaces:

CallbackEvaluationI, PostfixMathCommandI

Direct Known Subclasses:

Max, MaxArg, Min, MinArg, Product, Sum, Trapezium

public abstract class SumType
extends PostfixMathCommand
implements CallbackEvaluationI

Base class for functions like Sum(x^2,x,1,10) which finds the sum of x^2 with x running from 1 to 10. The first argument should be an equation, the second argument is a variable name, the third argument is the min value, the forth is the max value and the fifth argument (if present, default 1) is the increment to use. Sub classes should implement the

public abstract Object evaluate(Object elements[]) throws ParseException;

method, which is passed an array of the value

Author:

Rich Morris Created on 10-Sept-2004

Field Summary

Fields

Modifier and Type	Field and Description
protected String	name The name of the function, use in error reporting.

Fields inherited from class org.nfunk.jep.function.PostfixMathCommand

curNumberOfParameters, numberOfParameters

Constructor Summary

Constructors

Constructor and Description
SumType()
SumType(String funName)

Method Summary

Modifier and Type	Method and Description
boolean	checkNumberOfParameters(int n) Checks the number of parameters of the function.
Object	evaluate(Node node, EvaluatorI pv) Evaluates the operator in given context.
Object	evaluate(Node node, Variable var, double min, double max, double inc, EvaluatorI pv) Evaluates the node by repeatibly setting the value of the variable from min to max, and calculating the value of the first argument.
abstract Object	evaluate(Object[] elements) Evaluates the function given the set of y values.
void	run(Stack s) run method.

Methods inherited from class org.nfunk.jep.function.PostfixMathCommand

checkStack, getNumberOfParameters, setCurNumberOfParameters

Methods inherited from class java.lang.Object

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

Field Detail

name

protected String name

The name of the function, use in error reporting.

Constructor Detail

SumType

public SumType(String funName)

SumType

public SumType()

Method Detail

checkNumberOfParameters

public boolean checkNumberOfParameters(int n)

Description copied from class: PostfixMathCommand

Checks the number of parameters of the function. Functions which set numberOfParameter=-1 should overload this method

Specified by:

checkNumberOfParameters in interface PostfixMathCommandI

Overrides:

checkNumberOfParameters in class PostfixMathCommand

Parameters:

n - number of parameters function will be called with.

Returns:

False if an illegal number of parameters is supplied, true otherwise.

evaluate

public Object evaluate(Node node,
                       EvaluatorI pv)
                throws ParseException

Evaluates the operator in given context. Typically does not need to be sub-classed as the other evaluate methods are more useful. This method just checks the arguments.

Specified by:

evaluate in interface CallbackEvaluationI

Parameters:

node - The current node

pv - The visitor, can be used evaluate the children

Returns:

the value after evaluation

Throws:

ParseException

evaluate

public Object evaluate(Node node,
                       Variable var,
                       double min,
                       double max,
                       double inc,
                       EvaluatorI pv)
                throws ParseException

Evaluates the node by repeatibly setting the value of the variable from min to max, and calculating the value of the first argument. Sub classes generally do not need to implement this method as evaluate(Object[]) is more useful. If they do they should follow the pattern used here.

Parameters:

node -

var -

min -

max -

inc -

pv -

Returns:

the result of evaluation

Throws:

ParseException

evaluate

public abstract Object evaluate(Object[] elements)
                         throws ParseException

Evaluates the function given the set of y values. For example for Sum(x^2,x,1,5) the function will be passed the array [1,4,9,16,25].

Parameters:

elements - the y values

Returns:

the result of the function

Throws:

ParseException

run

public void run(Stack s)
         throws ParseException

run method. Should not be called.

Specified by:

run in interface PostfixMathCommandI

Overrides:

run in class PostfixMathCommand

Throws:

ParseException