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The Apache Commons Math project is a library of lightweight, self-contained mathematics and statistics components addressing the most common practical problems not immediately available in the Java programming language or commons-lang.
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.math3.transform;
/**
* This enumeration defines the various types of normalizations that can be
* applied to discrete sine transforms (DST). The exact definition of these
* normalizations is detailed below.
*
* @see FastSineTransformer
* @since 3.0
*/
public enum DstNormalization {
/**
* Should be passed to the constructor of {@link FastSineTransformer} to
* use the standard normalization convention. The standard DST-I
* normalization convention is defined as follows
*
* - forward transform: yn = ∑k=0N-1
* xk sin(π nk / N),
* - inverse transform: xk = (2 / N)
* ∑n=0N-1 yn sin(π nk / N),
*
* where N is the size of the data sample, and x0 = 0.
*/
STANDARD_DST_I,
/**
* Should be passed to the constructor of {@link FastSineTransformer} to
* use the orthogonal normalization convention. The orthogonal
* DCT-I normalization convention is defined as follows
*
* - Forward transform: yn = √(2 / N)
* ∑k=0N-1 xk sin(π nk / N),
* - Inverse transform: xk = √(2 / N)
* ∑n=0N-1 yn sin(π nk / N),
*
* which makes the transform orthogonal. N is the size of the data sample,
* and x0 = 0.
*/
ORTHOGONAL_DST_I
}