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
022 /**
023 * Interface for one-dimensional data sets transformations producing real results.
024 * <p>Such transforms include {@link FastSineTransformer sine transform},
025 * {@link FastCosineTransformer cosine transform} or {@link
026 * FastHadamardTransformer Hadamard transform}. {@link FastFourierTransformer
027 * Fourier transform} is of a different kind and does not implement this
028 * interface since it produces {@link org.apache.commons.math.complex.Complex complex}
029 * results instead of real ones.
030 * </p>
031 * @version $Revision: 811786 $ $Date: 2009-09-06 05:36:08 -0400 (Sun, 06 Sep 2009) $
032 * @since 2.0
033 */
034 public interface RealTransformer {
035
036 /**
037 * Transform the given real data set.
038 * @param f the real data array to be transformed (signal)
039 * @return the real transformed array (spectrum)
040 * @throws IllegalArgumentException if any parameters are invalid
041 */
042 double[] transform(double f[])
043 throws IllegalArgumentException;
044
045 /**
046 * Transform the given real function, sampled on the given interval.
047 * @param f the function to be sampled and transformed
048 * @param min the lower bound for the interval
049 * @param max the upper bound for the interval
050 * @param n the number of sample points
051 * @return the real transformed array
052 * @throws FunctionEvaluationException if function cannot be evaluated
053 * at some point
054 * @throws IllegalArgumentException if any parameters are invalid
055 */
056 double[] transform(UnivariateRealFunction f, double min, double max, int n)
057 throws FunctionEvaluationException, IllegalArgumentException;
058
059 /**
060 * Inversely transform the given real data set.
061 * @param f the real data array to be inversely transformed (spectrum)
062 * @return the real inversely transformed array (signal)
063 * @throws IllegalArgumentException if any parameters are invalid
064 */
065 double[] inversetransform(double f[])
066 throws IllegalArgumentException;
067
068 /**
069 * Inversely transform the given real function, sampled on the given interval.
070 * @param f the function to be sampled and inversely transformed
071 * @param min the lower bound for the interval
072 * @param max the upper bound for the interval
073 * @param n the number of sample points
074 * @return the real inversely transformed array
075 * @throws FunctionEvaluationException if function cannot be evaluated
076 * at some point
077 * @throws IllegalArgumentException if any parameters are invalid
078 */
079 double[] inversetransform(UnivariateRealFunction f, double min, double max, int n)
080 throws FunctionEvaluationException, IllegalArgumentException;
081
082 }