com.numericalmethod.suanshu.analysis.function.rn2r1.univariate

Class StepFunction

java.lang.Object

com.numericalmethod.suanshu.analysis.function.rn2r1.univariate.UnivariateRealFunction

com.numericalmethod.suanshu.analysis.function.rn2r1.univariate.StepFunction

All Implemented Interfaces:

Function<Vector,java.lang.Double>, RealScalarFunction, OrderedPairs, java.io.Serializable

public class StepFunction
extends UnivariateRealFunction
implements OrderedPairs

A step function (or staircase function) is a finite linear combination of indicator functions of intervals. Informally speaking, a step function is a piecewise constant function having only finitely many pieces.

Note: this function is mutable for convenience. It allows dynamically adding more points to the function. It is handy when, e.g., merging two sets of points.

See Also:

Wikipedia: Step function, Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface com.numericalmethod.suanshu.analysis.function.Function

Function.EvaluationException

Constructor Summary

Constructors

Constructor and Description
StepFunction(double epsilon) Construct an empty step function.
StepFunction(OrderedPairs f) Construct a step function from a collection ordered pairs.
StepFunction(OrderedPairs f, double epsilon) Construct a step function from a collection ordered pairs.

Method Summary

Modifier and Type	Method and Description
void	add(OrderedPairs f) Dynamically add points to the step function.
double	evaluate(double x) Evaluate y = f(x).
double	maxDomain() Get the biggest abscissae.
double	minDomain() Get the smallest abscissae.
int	size() Get the number of points.
double[]	x() Get the abscissae.
double[]	y() Get the ordinates.

Methods inherited from class com.numericalmethod.suanshu.analysis.function.rn2r1.univariate.UnivariateRealFunction

dimensionOfDomain, dimensionOfRange, evaluate

Methods inherited from class java.lang.Object

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

Constructor Detail

StepFunction

public StepFunction(double epsilon)

Construct an empty step function.

Parameters:

epsilon - a precision parameter: when a number |x| ≤ ε, it is considered 0

StepFunction

public StepFunction(OrderedPairs f,
                    double epsilon)

Construct a step function from a collection ordered pairs.

Parameters:

f - a collection of ordered pairs

epsilon - a precision parameter: when a number |x| ≤ ε, it is considered 0

StepFunction

public StepFunction(OrderedPairs f)

Construct a step function from a collection ordered pairs.

Parameters:

f - a collection of ordered pairs

Method Detail

add

public void add(OrderedPairs f)

Dynamically add points to the step function.

Parameters:

f - a collection of ordered pairs

x

public double[] x()

Description copied from interface: OrderedPairs

Get the abscissae.

Specified by:

x in interface OrderedPairs

Returns:

the abscissae

y

public double[] y()

Description copied from interface: OrderedPairs

Get the ordinates.

Specified by:

y in interface OrderedPairs

Returns:

the ordinates

minDomain

public double minDomain()

Get the smallest abscissae.

Returns:

the smallest abscissae

maxDomain

public double maxDomain()

Get the biggest abscissae.

Returns:

the biggest abscissae

size

public int size()

Description copied from interface: OrderedPairs

Get the number of points.

Specified by:

size in interface OrderedPairs

Returns:

the number of points

evaluate

public double evaluate(double x)

Description copied from class: UnivariateRealFunction

Evaluate y = f(x).

Specified by:

evaluate in class UnivariateRealFunction

Parameters:

x - x

Returns:

f(x)