Package org.opensourcephysics.numerics

Class ParsedMultiVarFunction

java.lang.Object

org.opensourcephysics.numerics.ParsedMultiVarFunction

All Implemented Interfaces:

MultiVarFunction

public final class ParsedMultiVarFunction
extends Object
implements MultiVarFunction

ParsedMultiVarFunction defines a function of multiple variables using a String. This function is immutable. That is, once an instance is created with a particular function string, the function cannot be changed. Because immutable objects cannot change, they are thread safe and can be freely shared in a Java program.

Author:

Wolfgang Christian

Field Summary

Fields

Modifier and Type	Field	Description
boolean	isNull

Constructor Summary

Constructors

Constructor	Description
ParsedMultiVarFunction(String _fStr, String[] var, boolean allowUnkownIdentifiers)	Constructs a ParsedFunction from the given string and independent variable.

Method Summary

Modifier and Type	Method	Description
double	evaluate(double[] x)	Evaluates the function, f.
boolean	evaluatedToNaN()	Determines if last evaluation resulted in NaN.
String[]	getFunctionNames()	Returns function names.
String	toString()	Represents the function as a string.

Methods inherited from class java.lang.Object

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

Field Details

isNull

public boolean isNull

Constructor Details

ParsedMultiVarFunction

public ParsedMultiVarFunction(String _fStr,
 String[] var,
 boolean allowUnkownIdentifiers)
                       throws ParserException

Constructs a ParsedFunction from the given string and independent variable.

Parameters:

_fStr - the function

var - the independent variable

allowUnknownIdentifiers - always false

Throws:

ParserException

Method Details

evaluate

public double evaluate(double[] x)

Evaluates the function, f.

Specified by:

evaluate in interface MultiVarFunction

Parameters:

x - the value of the independent variable

Returns:

the value of the function

toString

public String toString()

Represents the function as a string.

Overrides:

toString in class Object

Returns:

the string

getFunctionNames

public String[] getFunctionNames()

Returns function names. Added by D. Brown 06 Jul 2008

Returns:

array of function names

evaluatedToNaN

public boolean evaluatedToNaN()

Determines if last evaluation resulted in NaN. Added by D Brown 15 Sep 2010.

Returns:

true if result was converted from NaN to zero