magpie.utility

Class ParsedFunction

java.lang.Object

magpie.utility.ParsedFunction

All Implemented Interfaces:

java.io.Serializable, org.apache.commons.math3.analysis.MultivariateFunction

public class ParsedFunction
extends java.lang.Object
implements org.apache.commons.math3.analysis.MultivariateFunction, java.io.Serializable

Parses a function from text string.

Variables in the function must be surrounded by "#{" and "}" (think Bash, but using # instead of $ to denote variables), and should not contain any characters that would be confused with a math operation (e.g., +) or be named after a math function (e.g., cos). Also, don't put any whitespace inside the {}'s.

Dev note: This class *is not* thread safe.

See Also:

Parser, Serialized Form

Constructor Summary

Constructors

Constructor and Description
ParsedFunction(java.lang.String function) Parse a function from a text string.

Method Summary

Modifier and Type	Method and Description
double	evaluate() Evaluate function with current variable values
java.lang.String	getInput() Get the string that was provided as input
java.util.List<java.lang.String>	getVariableNames() Get the list of variables.
int	numVariables() Print the number of variables this function expects
void	setVariable(int index, double val) Define the value of a certain variable in this expression
void	setVariable(java.lang.String name, double val) Define the value of a certain variable in this expression
double	value(double[] point)

Methods inherited from class java.lang.Object

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

Constructor Detail

ParsedFunction

public ParsedFunction(java.lang.String function)
               throws java.lang.Exception

Parse a function from a text string. Uses the Expr Java library.

Parameters:

function - Function to be parsed. See Javadoc for format

Throws:

java.lang.Exception

Method Detail

getVariableNames

public java.util.List<java.lang.String> getVariableNames()

Get the list of variables. Returns them in the same order expected by {@linkplain #value(double[]) )

Returns:

getInput

public java.lang.String getInput()

Get the string that was provided as input

Returns:

Input string

setVariable

public void setVariable(java.lang.String name,
                        double val)
                 throws java.lang.Exception

Define the value of a certain variable in this expression

Parameters:

name - Name of variable

val - Desired value

Throws:

java.lang.Exception

setVariable

public void setVariable(int index,
                        double val)

Define the value of a certain variable in this expression

Parameters:

index - Index of variable

val - Desired value

numVariables

public int numVariables()

Print the number of variables this function expects

Returns:

Number of variables

value

public double value(double[] point)

Specified by:

value in interface org.apache.commons.math3.analysis.MultivariateFunction

evaluate

public double evaluate()

Evaluate function with current variable values

Returns:

Value of function