org.apache.commons.math3.transform

Enum DctNormalization

java.lang.Object

java.lang.Enum<DctNormalization>

org.apache.commons.math3.transform.DctNormalization

All Implemented Interfaces:

Serializable, Comparable<DctNormalization>

public enum DctNormalization
extends Enum<DctNormalization>

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

Since:

3.0

Version:

$Id: DctNormalization.java 1244107 2012-02-14 16:17:55Z erans $

See Also:

FastCosineTransformer

Enum Constant Summary

Enum Constants

Enum Constant and Description
ORTHOGONAL_DCT_I Should be passed to the constructor of FastCosineTransformer to use the orthogonal normalization convention.
STANDARD_DCT_I Should be passed to the constructor of FastCosineTransformer to use the standard normalization convention.

Method Summary

Methods

Modifier and Type	Method and Description
static DctNormalization	valueOf(String name) Returns the enum constant of this type with the specified name.
static DctNormalization[]	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_DCT_I

public static final DctNormalization STANDARD_DCT_I

Should be passed to the constructor of FastCosineTransformer to use the standard normalization convention. The standard DCT-I normalization convention is defined as follows

• forward transform: y_n = (1/2) [x₀ + (-1)ⁿx_N-1] + ∑_k=1^N-2 x_k cos[π nk / (N - 1)],
• inverse transform: x_k = [1 / (N - 1)] [y₀ + (-1)^ky_N-1] + [2 / (N - 1)] ∑_n=1^N-2 y_n cos[π nk / (N - 1)],

where N is the size of the data sample.

ORTHOGONAL_DCT_I

public static final DctNormalization ORTHOGONAL_DCT_I

Should be passed to the constructor of FastCosineTransformer to use the orthogonal normalization convention. The orthogonal DCT-I normalization convention is defined as follows

• forward transform: y_n = [2(N - 1)]^-1/2 [x₀ + (-1)ⁿx_N-1] + [2 / (N - 1)]^1/2 ∑_k=1^N-2 x_k cos[π nk / (N - 1)],
• inverse transform: x_k = [2(N - 1)]^-1/2 [y₀ + (-1)^ky_N-1] + [2 / (N - 1)]^1/2 ∑_n=1^N-2 y_n cos[π nk / (N - 1)],

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

Method Detail

values

public static DctNormalization[] 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 (DctNormalization c : DctNormalization.values())
    System.out.println(c);

Returns:

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

valueOf

public static DctNormalization valueOf(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:

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

NullPointerException - if the argument is null