001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.commons.math.transform; 018 019 import org.apache.commons.math.FunctionEvaluationException; 020 import org.apache.commons.math.analysis.UnivariateRealFunction; 021 import org.apache.commons.math.complex.Complex; 022 023 /** 024 * Interface for one-dimensional data sets transformations producing real results. 025 * <p>Such transforms include {@link FastSineTransformer sine transform}, 026 * {@link FastCosineTransformer cosine transform} or {@link 027 * FastHadamardTransformer Hadamard transform}. {@link FastFourierTransformer 028 * Fourier transform} is of a different kind and does not implement this 029 * interface since it produces {@link Complex complex} results instead of real 030 * ones. 031 * </p> 032 * @version $Revision: 780541 $ $Date: 2009-05-31 20:47:02 -0400 (Sun, 31 May 2009) $ 033 * @since 2.0 034 */ 035 public interface RealTransformer { 036 037 /** 038 * Transform the given real data set. 039 * @param f the real data array to be transformed (signal) 040 * @return the real transformed array (spectrum) 041 * @throws IllegalArgumentException if any parameters are invalid 042 */ 043 double[] transform(double f[]) 044 throws IllegalArgumentException; 045 046 /** 047 * Transform the given real function, sampled on the given interval. 048 * @param f the function to be sampled and transformed 049 * @param min the lower bound for the interval 050 * @param max the upper bound for the interval 051 * @param n the number of sample points 052 * @return the real transformed array 053 * @throws FunctionEvaluationException if function cannot be evaluated 054 * at some point 055 * @throws IllegalArgumentException if any parameters are invalid 056 */ 057 double[] transform(UnivariateRealFunction f, double min, double max, int n) 058 throws FunctionEvaluationException, IllegalArgumentException; 059 060 /** 061 * Inversely transform the given real data set. 062 * @param f the real data array to be inversely transformed (spectrum) 063 * @return the real inversely transformed array (signal) 064 * @throws IllegalArgumentException if any parameters are invalid 065 */ 066 public abstract double[] inversetransform(double f[]) 067 throws IllegalArgumentException; 068 069 /** 070 * Inversely transform the given real function, sampled on the given interval. 071 * @param f the function to be sampled and inversely transformed 072 * @param min the lower bound for the interval 073 * @param max the upper bound for the interval 074 * @param n the number of sample points 075 * @return the real inversely transformed array 076 * @throws FunctionEvaluationException if function cannot be evaluated 077 * at some point 078 * @throws IllegalArgumentException if any parameters are invalid 079 */ 080 double[] inversetransform(UnivariateRealFunction f, double min, double max, int n) 081 throws FunctionEvaluationException, IllegalArgumentException; 082 083 }