| /* |
| * 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.math3.transform; |
| |
| import java.util.Arrays; |
| import java.util.Collection; |
| |
| import org.apache.commons.math3.analysis.UnivariateFunction; |
| import org.apache.commons.math3.analysis.function.Sin; |
| import org.apache.commons.math3.analysis.function.Sinc; |
| import org.apache.commons.math3.exception.MathIllegalArgumentException; |
| import org.apache.commons.math3.exception.MathIllegalStateException; |
| import org.apache.commons.math3.util.FastMath; |
| import org.junit.Assert; |
| import org.junit.Test; |
| import org.junit.runner.RunWith; |
| import org.junit.runners.Parameterized; |
| import org.junit.runners.Parameterized.Parameters; |
| |
| /** |
| * Test case for fast sine transformer. |
| * <p> |
| * FST algorithm is exact, the small tolerance number is used only |
| * to account for round-off errors. |
| * |
| */ |
| @RunWith(value = Parameterized.class) |
| public final class FastSineTransformerTest extends RealTransformerAbstractTest { |
| |
| private final DstNormalization normalization; |
| |
| private final int[] invalidDataSize; |
| |
| private final double[] relativeTolerance; |
| |
| private final int[] validDataSize; |
| |
| public FastSineTransformerTest(final DstNormalization normalization) { |
| this.normalization = normalization; |
| this.validDataSize = new int[] { |
| 1, 2, 4, 8, 16, 32, 64, 128 |
| }; |
| this.invalidDataSize = new int[] { |
| 129 |
| }; |
| this.relativeTolerance = new double[] { |
| 1E-15, 1E-15, 1E-14, 1E-14, 1E-13, 1E-12, 1E-11, 1E-11 |
| }; |
| } |
| |
| /** |
| * Returns an array containing {@code true, false} in order to check both |
| * standard and orthogonal DSTs. |
| * |
| * @return an array of parameters for this parameterized test |
| */ |
| @Parameters |
| public static Collection<Object[]> data() { |
| final DstNormalization[] normalization = DstNormalization.values(); |
| final Object[][] data = new DstNormalization[normalization.length][1]; |
| for (int i = 0; i < normalization.length; i++) { |
| data[i][0] = normalization[i]; |
| } |
| return Arrays.asList(data); |
| } |
| |
| /** |
| * {@inheritDoc} |
| * |
| * Overriding the default implementation allows to ensure that the first |
| * element of the data set is zero. |
| */ |
| @Override |
| double[] createRealData(final int n) { |
| final double[] data = super.createRealData(n); |
| data[0] = 0.0; |
| return data; |
| } |
| |
| @Override |
| RealTransformer createRealTransformer() { |
| return new FastSineTransformer(normalization); |
| } |
| |
| @Override |
| int getInvalidDataSize(final int i) { |
| return invalidDataSize[i]; |
| } |
| |
| @Override |
| int getNumberOfInvalidDataSizes() { |
| return invalidDataSize.length; |
| } |
| |
| @Override |
| int getNumberOfValidDataSizes() { |
| return validDataSize.length; |
| } |
| |
| @Override |
| double getRelativeTolerance(final int i) { |
| return relativeTolerance[i]; |
| } |
| |
| @Override |
| int getValidDataSize(final int i) { |
| return validDataSize[i]; |
| } |
| |
| @Override |
| UnivariateFunction getValidFunction() { |
| return new Sinc(); |
| } |
| |
| @Override |
| double getValidLowerBound() { |
| return 0.0; |
| } |
| |
| @Override |
| double getValidUpperBound() { |
| return FastMath.PI; |
| } |
| |
| @Override |
| double[] transform(final double[] x, final TransformType type) { |
| final int n = x.length; |
| final double[] y = new double[n]; |
| final double[] sin = new double[2 * n]; |
| for (int i = 0; i < sin.length; i++) { |
| sin[i] = FastMath.sin(FastMath.PI * i / n); |
| } |
| for (int j = 0; j < n; j++) { |
| double yj = 0.0; |
| for (int i = 0; i < n; i++) { |
| yj += x[i] * sin[(i * j) % sin.length]; |
| } |
| y[j] = yj; |
| } |
| final double s; |
| if (type == TransformType.FORWARD) { |
| if (normalization == DstNormalization.STANDARD_DST_I) { |
| s = 1.0; |
| } else if (normalization == DstNormalization.ORTHOGONAL_DST_I) { |
| s = FastMath.sqrt(2.0 / n); |
| } else { |
| throw new MathIllegalStateException(); |
| } |
| } else if (type == TransformType.INVERSE) { |
| if (normalization == DstNormalization.STANDARD_DST_I) { |
| s = 2.0 / n; |
| } else if (normalization == DstNormalization.ORTHOGONAL_DST_I) { |
| s = FastMath.sqrt(2.0 / n); |
| } else { |
| throw new MathIllegalStateException(); |
| } |
| } else { |
| /* |
| * Should never occur. This clause is a safeguard in case other |
| * types are used to TransformType (which should not be done). |
| */ |
| throw new MathIllegalStateException(); |
| } |
| TransformUtils.scaleArray(y, s); |
| return y; |
| } |
| |
| /* |
| * Additional tests. |
| */ |
| @Test |
| public void testTransformRealFirstElementNotZero() { |
| final TransformType[] type = TransformType.values(); |
| final double[] data = new double[] { |
| 1.0, 1.0, 1.0, 1.0 |
| }; |
| final RealTransformer transformer = createRealTransformer(); |
| for (int j = 0; j < type.length; j++) { |
| try { |
| transformer.transform(data, type[j]); |
| Assert.fail(type[j].toString()); |
| } catch (MathIllegalArgumentException e) { |
| // Expected: do nothing |
| } |
| } |
| } |
| |
| /* |
| * Additional (legacy) tests. |
| */ |
| |
| /** |
| * Test of transformer for the ad hoc data. |
| */ |
| @Test |
| public void testAdHocData() { |
| FastSineTransformer transformer; |
| transformer = new FastSineTransformer(DstNormalization.STANDARD_DST_I); |
| double result[], tolerance = 1E-12; |
| |
| double x[] = { 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0 }; |
| double y[] = { 0.0, 20.1093579685034, -9.65685424949238, |
| 5.98642305066196, -4.0, 2.67271455167720, |
| -1.65685424949238, 0.795649469518633 }; |
| |
| result = transformer.transform(x, TransformType.FORWARD); |
| for (int i = 0; i < result.length; i++) { |
| Assert.assertEquals(y[i], result[i], tolerance); |
| } |
| |
| result = transformer.transform(y, TransformType.INVERSE); |
| for (int i = 0; i < result.length; i++) { |
| Assert.assertEquals(x[i], result[i], tolerance); |
| } |
| |
| TransformUtils.scaleArray(x, FastMath.sqrt(x.length / 2.0)); |
| transformer = new FastSineTransformer(DstNormalization.ORTHOGONAL_DST_I); |
| |
| result = transformer.transform(y, TransformType.FORWARD); |
| for (int i = 0; i < result.length; i++) { |
| Assert.assertEquals(x[i], result[i], tolerance); |
| } |
| |
| result = transformer.transform(x, TransformType.INVERSE); |
| for (int i = 0; i < result.length; i++) { |
| Assert.assertEquals(y[i], result[i], tolerance); |
| } |
| } |
| |
| /** |
| * Test of transformer for the sine function. |
| */ |
| @Test |
| public void testSinFunction() { |
| UnivariateFunction f = new Sin(); |
| FastSineTransformer transformer; |
| transformer = new FastSineTransformer(DstNormalization.STANDARD_DST_I); |
| double min, max, result[], tolerance = 1E-12; int N = 1 << 8; |
| |
| min = 0.0; max = 2.0 * FastMath.PI; |
| result = transformer.transform(f, min, max, N, TransformType.FORWARD); |
| Assert.assertEquals(N >> 1, result[2], tolerance); |
| for (int i = 0; i < N; i += (i == 1 ? 2 : 1)) { |
| Assert.assertEquals(0.0, result[i], tolerance); |
| } |
| |
| min = -FastMath.PI; max = FastMath.PI; |
| result = transformer.transform(f, min, max, N, TransformType.FORWARD); |
| Assert.assertEquals(-(N >> 1), result[2], tolerance); |
| for (int i = 0; i < N; i += (i == 1 ? 2 : 1)) { |
| Assert.assertEquals(0.0, result[i], tolerance); |
| } |
| } |
| |
| /** |
| * Test of parameters for the transformer. |
| */ |
| @Test |
| public void testParameters() throws Exception { |
| UnivariateFunction f = new Sin(); |
| FastSineTransformer transformer; |
| transformer = new FastSineTransformer(DstNormalization.STANDARD_DST_I); |
| |
| try { |
| // bad interval |
| transformer.transform(f, 1, -1, 64, TransformType.FORWARD); |
| Assert.fail("Expecting IllegalArgumentException - bad interval"); |
| } catch (IllegalArgumentException ex) { |
| // expected |
| } |
| try { |
| // bad samples number |
| transformer.transform(f, -1, 1, 0, TransformType.FORWARD); |
| Assert.fail("Expecting IllegalArgumentException - bad samples number"); |
| } catch (IllegalArgumentException ex) { |
| // expected |
| } |
| try { |
| // bad samples number |
| transformer.transform(f, -1, 1, 100, TransformType.FORWARD); |
| Assert.fail("Expecting IllegalArgumentException - bad samples number"); |
| } catch (IllegalArgumentException ex) { |
| // expected |
| } |
| } |
| } |