org.apache.commons.math3.transform

Enum DftNormalization

java.lang.Object

java.lang.Enum<DftNormalization>

org.apache.commons.math3.transform.DftNormalization

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<DftNormalization>

public enum DftNormalization
extends java.lang.Enum<DftNormalization>

This enumeration defines the various types of normalizations that can be applied to discrete Fourier transforms (DFT). The exact definition of these normalizations is detailed below.

Since:

3.0

See Also:

FastFourierTransformer

Enum Constant Summary

Enum Constants

Enum Constant and Description
STANDARD Should be passed to the constructor of FastFourierTransformer to use the standard normalization convention.
UNITARY Should be passed to the constructor of FastFourierTransformer to use the unitary normalization convention.

Method Summary

Methods

Modifier and Type	Method and Description
static DftNormalization	valueOf(java.lang.String name) Returns the enum constant of this type with the specified name.
static DftNormalization[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

STANDARD

public static final DftNormalization STANDARD

Should be passed to the constructor of FastFourierTransformer to use the standard normalization convention. This normalization convention is defined as follows

• forward transform: y_n = ∑_k=0^N-1 x_k exp(-2πi n k / N),
• inverse transform: x_k = N^-1 ∑_n=0^N-1 y_n exp(2πi n k / N),

where N is the size of the data sample.

UNITARY

public static final DftNormalization UNITARY

Should be passed to the constructor of FastFourierTransformer to use the unitary normalization convention. This normalization convention is defined as follows

• forward transform: y_n = (1 / √N) ∑_k=0^N-1 x_k exp(-2πi n k / N),
• inverse transform: x_k = (1 / √N) ∑_n=0^N-1 y_n exp(2πi n k / N),

which makes the transform unitary. N is the size of the data sample.

Method Detail

values

public static DftNormalization[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (DftNormalization c : DftNormalization.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static DftNormalization valueOf(java.lang.String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

java.lang.IllegalArgumentException - if this enum type has no constant with the specified name

java.lang.NullPointerException - if the argument is null