org.apache.commons.math3.transform
Class AbstractFastFourierTransformer

java.lang.Object
  org.apache.commons.math3.transform.AbstractFastFourierTransformer

All Implemented Interfaces:

IFastFourierTransformer

Direct Known Subclasses:

FastFourierTransformer

public abstract class AbstractFastFourierTransformer
extends Object
implements IFastFourierTransformer

This abstract class is common to all FFT algorithms of this library.

Since:

2.3

Version:

$Id: AbstractFastFourierTransformer.java 17601 2017-05-18 07:27:52Z bignon $

Constructor Summary

AbstractFastFourierTransformer(DftNormalization dftNormalization)
Creates a new instance of this class, with various normalization conventions.

Method Summary

DftNormalization	getNormalization() Gets the private attribute normalization.
protected static void	normalizeTransformedData(double[][] dataRI, DftNormalization normalization, TransformType type) Applies the proper normalization to the specified transformed data.
Complex[]	transform(UnivariateFunction f, double min, double max, int n, TransformType type) Returns the (forward, inverse) transform of the specified real function, sampled on the specified interval.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.commons.math3.transform.IFastFourierTransformer

transform, transform

Constructor Detail

AbstractFastFourierTransformer

public AbstractFastFourierTransformer(DftNormalization dftNormalization)

Creates a new instance of this class, with various normalization conventions.

Parameters:

dftNormalization - the type of normalization to be applied to the transformed data

Method Detail

transform

public Complex[] transform(UnivariateFunction f,
                           double min,
                           double max,
                           int n,
                           TransformType type)

Returns the (forward, inverse) transform of the specified real function, sampled on the specified interval.

Specified by:

transform in interface IFastFourierTransformer

Parameters:

f - the function to be sampled and transformed

min - the (inclusive) lower bound for the interval

max - the (exclusive) upper bound for the interval

n - the number of sample points

type - the type of transform (forward, inverse) to be performed

Returns:

the complex transformed array

normalizeTransformedData

protected static void normalizeTransformedData(double[][] dataRI,
                                               DftNormalization normalization,
                                               TransformType type)

Applies the proper normalization to the specified transformed data.

Parameters:

dataRI - the unscaled transformed data

normalization - the normalization to be applied

type - the type of transform (forward, inverse) which resulted in the specified data

getNormalization

public DftNormalization getNormalization()

Gets the private attribute normalization.

Returns:

normalization : an enum DftNormalization equal to STANDARD or UNITARY