1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.math.transform; 18 19 import org.apache.commons.math.FunctionEvaluationException; 20 import org.apache.commons.math.analysis.UnivariateRealFunction; 21 import org.apache.commons.math.complex.Complex; 22 23 /** 24 * Interface for one-dimensional data sets transformations producing real results. 25 * <p>Such transforms include {@link FastSineTransformer sine transform}, 26 * {@link FastCosineTransformer cosine transform} or {@link 27 * FastHadamardTransformer Hadamard transform}. {@link FastFourierTransformer 28 * Fourier transform} is of a different kind and does not implement this 29 * interface since it produces {@link Complex complex} results instead of real 30 * ones. 31 * </p> 32 * @version $Revision: 780541 $ $Date: 2009-05-31 20:47:02 -0400 (Sun, 31 May 2009) $ 33 * @since 2.0 34 */ 35 public interface RealTransformer { 36 37 /** 38 * Transform the given real data set. 39 * @param f the real data array to be transformed (signal) 40 * @return the real transformed array (spectrum) 41 * @throws IllegalArgumentException if any parameters are invalid 42 */ 43 double[] transform(double f[]) 44 throws IllegalArgumentException; 45 46 /** 47 * Transform the given real function, sampled on the given interval. 48 * @param f the function to be sampled and transformed 49 * @param min the lower bound for the interval 50 * @param max the upper bound for the interval 51 * @param n the number of sample points 52 * @return the real transformed array 53 * @throws FunctionEvaluationException if function cannot be evaluated 54 * at some point 55 * @throws IllegalArgumentException if any parameters are invalid 56 */ 57 double[] transform(UnivariateRealFunction f, double min, double max, int n) 58 throws FunctionEvaluationException, IllegalArgumentException; 59 60 /** 61 * Inversely transform the given real data set. 62 * @param f the real data array to be inversely transformed (spectrum) 63 * @return the real inversely transformed array (signal) 64 * @throws IllegalArgumentException if any parameters are invalid 65 */ 66 public abstract double[] inversetransform(double f[]) 67 throws IllegalArgumentException; 68 69 /** 70 * Inversely transform the given real function, sampled on the given interval. 71 * @param f the function to be sampled and inversely transformed 72 * @param min the lower bound for the interval 73 * @param max the upper bound for the interval 74 * @param n the number of sample points 75 * @return the real inversely transformed array 76 * @throws FunctionEvaluationException if function cannot be evaluated 77 * at some point 78 * @throws IllegalArgumentException if any parameters are invalid 79 */ 80 double[] inversetransform(UnivariateRealFunction f, double min, double max, int n) 81 throws FunctionEvaluationException, IllegalArgumentException; 82 83 }