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Commons Math example source code file (FastCosineTransformerTest.java)
The Commons Math FastCosineTransformerTest.java source code/* * 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.math.transform; import org.apache.commons.math.analysis.*; import org.apache.commons.math.MathException; import junit.framework.TestCase; /** * Testcase for fast cosine transformer. * <p> * FCT algorithm is exact, the small tolerance number is used only * to account for round-off errors. * * @version $Revision: 811685 $ $Date: 2009-09-05 13:36:48 -0400 (Sat, 05 Sep 2009) $ */ public final class FastCosineTransformerTest extends TestCase { /** * Test of transformer for the ad hoc data. */ public void testAdHocData() { FastCosineTransformer transformer = new FastCosineTransformer(); double result[], tolerance = 1E-12; double x[] = { 0.0, 1.0, 4.0, 9.0, 16.0, 25.0, 36.0, 49.0, 64.0 }; double y[] = { 172.0, -105.096569476353, 27.3137084989848, -12.9593152353742, 8.0, -5.78585076868676, 4.68629150101524, -4.15826451958632, 4.0 }; result = transformer.transform(x); for (int i = 0; i < result.length; i++) { assertEquals(y[i], result[i], tolerance); } result = transformer.inversetransform(y); for (int i = 0; i < result.length; i++) { assertEquals(x[i], result[i], tolerance); } FastFourierTransformer.scaleArray(x, Math.sqrt(0.5 * (x.length-1))); result = transformer.transform2(y); for (int i = 0; i < result.length; i++) { assertEquals(x[i], result[i], tolerance); } result = transformer.inversetransform2(x); for (int i = 0; i < result.length; i++) { assertEquals(y[i], result[i], tolerance); } } /** * Test of transformer for the sine function. */ public void testSinFunction() throws MathException { UnivariateRealFunction f = new SinFunction(); FastCosineTransformer transformer = new FastCosineTransformer(); double min, max, result[], tolerance = 1E-12; int N = 9; double expected[] = { 0.0, 3.26197262739567, 0.0, -2.17958042710327, 0.0, -0.648846697642915, 0.0, -0.433545502649478, 0.0 }; min = 0.0; max = 2.0 * Math.PI * N / (N-1); result = transformer.transform(f, min, max, N); for (int i = 0; i < N; i++) { assertEquals(expected[i], result[i], tolerance); } min = -Math.PI; max = Math.PI * (N+1) / (N-1); result = transformer.transform(f, min, max, N); for (int i = 0; i < N; i++) { assertEquals(-expected[i], result[i], tolerance); } } /** * Test of parameters for the transformer. */ public void testParameters() throws Exception { UnivariateRealFunction f = new SinFunction(); FastCosineTransformer transformer = new FastCosineTransformer(); try { // bad interval transformer.transform(f, 1, -1, 65); fail("Expecting IllegalArgumentException - bad interval"); } catch (IllegalArgumentException ex) { // expected } try { // bad samples number transformer.transform(f, -1, 1, 1); fail("Expecting IllegalArgumentException - bad samples number"); } catch (IllegalArgumentException ex) { // expected } try { // bad samples number transformer.transform(f, -1, 1, 64); fail("Expecting IllegalArgumentException - bad samples number"); } catch (IllegalArgumentException ex) { // expected } } } Other Commons Math examples (source code examples)Here is a short list of links related to this Commons Math FastCosineTransformerTest.java source code file: |
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