org.jscience.mathematics.analysis
Class PrimitiveMappingSampler

java.lang.Object
  org.jscience.mathematics.analysis.PrimitiveMappingSampler

All Implemented Interfaces:

java.io.Serializable, SampledMapping

public class PrimitiveMappingSampler
extends java.lang.Object
implements SampledMapping, java.io.Serializable

This class is a wrapper allowing to sample a PrimitiveMapping.

The sample produced is a regular sample. It can be specified by several means :

• from an initial point a step and a number of points
• from a range and a number of points
• from a range and a step between points.

In the latter case, the step can optionaly be adjusted in order to have the last point exactly at the upper bound of the range.

The sample points are computed on demand, they are not stored. This allow to use this method for very large sample with little memory overhead. The drawback is that if the same sample points are going to be requested several times, they will be recomputed each time. In this case, the user should consider storing the points by some other means.

See Also:

PrimitiveMapping, Serialized Form

Constructor Summary

PrimitiveMappingSampler(PrimitiveMapping function, double[] range, double step, boolean adjustStep)
Constructor.

PrimitiveMappingSampler(PrimitiveMapping function, double[] range, int n)
Constructor.

PrimitiveMappingSampler(PrimitiveMapping function, double begin, double step, int n)
Constructor.

Method Summary

int	numInputDimensions() Get the dimension of the input values of the function.
int	numOutputDimensions() Get the dimension of the output values of the function.
ValuedPair	samplePointAt(int index) Get the abscissa and value of the sample at the specified index.
int	size() Get the number of points in the sample.

Methods inherited from class java.lang.Object

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

Constructor Detail

PrimitiveMappingSampler

public PrimitiveMappingSampler(PrimitiveMapping function,
                               double begin,
                               double step,
                               int n)

Constructor.

Build a sample from an PrimitiveMapping. Beware of the classical off-by-one problem ! If you want to have a sample like this : 0.0, 0.1, 0.2 ..., 1.0, then you should specify step = 0.1 and n = 11 (not n = 10).

Parameters:

begin - beginning of the range (will be the abscissa of the first point)

step - step between points

n - number of points

PrimitiveMappingSampler

public PrimitiveMappingSampler(PrimitiveMapping function,
                               double[] range,
                               int n)

Constructor. Build a sample from an PrimitiveMapping.

Parameters:

range - abscissa range (from range [0] to range [1])

n - number of points

PrimitiveMappingSampler

public PrimitiveMappingSampler(PrimitiveMapping function,
                               double[] range,
                               double step,
                               boolean adjustStep)

Constructor. Build a sample from an PrimitiveMapping.

Parameters:

range - abscissa range (from range [0] to range [1])

step - step between points

adjustStep - if true, the step is reduced in order to have the last point of the sample exactly at range [1], if false the last point will be between range [1] - step and range [1]

Method Detail

size

public int size()

Description copied from interface: SampledMapping

Get the number of points in the sample.

Specified by:

size in interface SampledMapping

Returns:

number of points in the sample

numInputDimensions

public int numInputDimensions()

Get the dimension of the input values of the function.

Specified by:

numInputDimensions in interface SampledMapping

Returns:

dimension

numOutputDimensions

public int numOutputDimensions()

Get the dimension of the output values of the function.

Specified by:

numOutputDimensions in interface SampledMapping

Returns:

dimension

samplePointAt

public ValuedPair samplePointAt(int index)
                         throws java.lang.ArrayIndexOutOfBoundsException

Description copied from interface: SampledMapping

Get the abscissa and value of the sample at the specified index.

Specified by:

samplePointAt in interface SampledMapping

Parameters:

index - index in the sample, should be between 0 and SampledMapping.size() - 1

Returns:

abscissa and value of the sample at the specified index

Throws:

java.lang.ArrayIndexOutOfBoundsException - if the index is wrong