| /* |
| * 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.math4.transform; |
| |
| import org.junit.Assert; |
| import org.junit.Test; |
| |
| import org.apache.commons.numbers.core.Precision; |
| |
| |
| /** |
| * Test for {@link FastHadamardTransform}. |
| */ |
| public final class FastHadamardTransformerTest { |
| /** |
| * Test of transformer for the a 8-point FHT (means n=8) |
| */ |
| @Test |
| public void test8Points() { |
| checkAllTransforms(new int[] {1, 4, -2, 3, 0, 1, 4, -1}, |
| new int[] {10, -4, 2, -4, 2, -12, 6, 8}); |
| } |
| |
| /** |
| * Test of transformer for the a 4-points FHT (means n=4) |
| */ |
| @Test |
| public void test4Points() { |
| checkAllTransforms(new int[] {1, 2, 3, 4}, |
| new int[] {10, -2, -4, 0}); |
| } |
| |
| /** |
| * Test the inverse transform of an integer vector is not always an integer vector |
| */ |
| @Test |
| public void testNoIntInverse() { |
| final FastHadamardTransform transformer = new FastHadamardTransform(true); |
| final double[] x = transformer.apply(new double[] {0, 1, 0, 1}); |
| Assert.assertEquals(0.5, x[0], 0); |
| Assert.assertEquals(-0.5, x[1], 0); |
| Assert.assertEquals(0.0, x[2], 0); |
| Assert.assertEquals(0.0, x[3], 0); |
| } |
| |
| /** |
| * Test of transformer for wrong number of points |
| */ |
| @Test |
| public void test3Points() { |
| try { |
| new FastHadamardTransform().apply(new double[3]); |
| Assert.fail("an exception should have been thrown"); |
| } catch (IllegalArgumentException iae) { |
| // expected |
| } |
| } |
| |
| private void checkAllTransforms(int[] x, int[] y) { |
| checkDoubleTransform(x, y); |
| checkInverseDoubleTransform(x, y); |
| checkIntTransform(x, y); |
| } |
| |
| private void checkDoubleTransform(int[] x, int[] y) { |
| // Initiate the transformer |
| final FastHadamardTransform transformer = new FastHadamardTransform(); |
| |
| // check double transform |
| final double[] dX = new double[x.length]; |
| for (int i = 0; i < dX.length; ++i) { |
| dX[i] = x[i]; |
| } |
| final double[] dResult = transformer.apply(dX); |
| for (int i = 0; i < dResult.length; i++) { |
| // compare computed results to precomputed results |
| Assert.assertTrue(Precision.equals(y[i], dResult[i], 1)); |
| } |
| } |
| |
| private void checkIntTransform(int[] x, int[] y) { |
| // Initiate the transformer |
| final FastHadamardTransform transformer = new FastHadamardTransform(); |
| |
| // check integer transform |
| final int[] iResult = transformer.apply(x); |
| for (int i = 0; i < iResult.length; i++) { |
| // compare computed results to precomputed results |
| Assert.assertEquals(y[i], iResult[i]); |
| } |
| } |
| |
| private void checkInverseDoubleTransform(int[]x, int[] y) { |
| // Initiate the transformer |
| final FastHadamardTransform transformer = new FastHadamardTransform(true); |
| |
| // check double transform |
| final double[] dY = new double[y.length]; |
| for (int i = 0; i < dY.length; ++i) { |
| dY[i] = y[i]; |
| } |
| final double[] dResult = transformer.apply(dY); |
| for (int i = 0; i < dResult.length; i++) { |
| // compare computed results to precomputed results |
| Assert.assertTrue(Precision.equals(x[i], dResult[i], 1)); |
| } |
| } |
| } |