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.math3.transform; 018 019 import org.apache.commons.math3.analysis.UnivariateFunction; 020 import org.apache.commons.math3.exception.MathIllegalArgumentException; 021 import org.apache.commons.math3.exception.NonMonotonicSequenceException; 022 import org.apache.commons.math3.exception.NotStrictlyPositiveException; 023 024 /** 025 * Interface for one-dimensional data sets transformations producing real results. 026 * <p> 027 * Such transforms include {@link FastSineTransformer sine transform}, 028 * {@link FastCosineTransformer cosine transform} or {@link 029 * FastHadamardTransformer Hadamard transform}. {@link FastFourierTransformer 030 * Fourier transform} is of a different kind and does not implement this 031 * interface since it produces {@link org.apache.commons.math3.complex.Complex} 032 * results instead of real ones. 033 * 034 * @version $Id: RealTransformer.java 1385310 2012-09-16 16:32:10Z tn $ 035 * @since 2.0 036 */ 037 public interface RealTransformer { 038 039 /** 040 * Returns the (forward, inverse) transform of the specified real data set. 041 * 042 * @param f the real data array to be transformed (signal) 043 * @param type the type of transform (forward, inverse) to be performed 044 * @return the real transformed array (spectrum) 045 * @throws MathIllegalArgumentException if the array cannot be transformed 046 * with the given type (this may be for example due to array size, which is 047 * constrained in some transforms) 048 */ 049 double[] transform(double[] f, TransformType type) throws MathIllegalArgumentException; 050 051 /** 052 * Returns the (forward, inverse) transform of the specified real function, 053 * sampled on the specified interval. 054 * 055 * @param f the function to be sampled and transformed 056 * @param min the (inclusive) lower bound for the interval 057 * @param max the (exclusive) upper bound for the interval 058 * @param n the number of sample points 059 * @param type the type of transform (forward, inverse) to be performed 060 * @return the real transformed array 061 * @throws NonMonotonicSequenceException if the lower bound is greater than, or equal to the upper bound 062 * @throws NotStrictlyPositiveException if the number of sample points is negative 063 * @throws MathIllegalArgumentException if the sample cannot be transformed 064 * with the given type (this may be for example due to sample size, which is 065 * constrained in some transforms) 066 */ 067 double[] transform(UnivariateFunction f, double min, double max, int n, 068 TransformType type) 069 throws NonMonotonicSequenceException, NotStrictlyPositiveException, MathIllegalArgumentException; 070 071 }