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Diffstat (limited to 'src/test/java/com/jsyn/util/TestFFT.java')
| -rw-r--r-- | src/test/java/com/jsyn/util/TestFFT.java | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/src/test/java/com/jsyn/util/TestFFT.java b/src/test/java/com/jsyn/util/TestFFT.java new file mode 100644 index 0000000..5d130c5 --- /dev/null +++ b/src/test/java/com/jsyn/util/TestFFT.java @@ -0,0 +1,201 @@ +/* + * Copyright 2009 Phil Burk, Mobileer Inc + * + * Licensed 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 com.jsyn.util; + +import com.softsynth.math.FourierMath; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import static org.junit.jupiter.api.Assertions.assertEquals; + +public class TestFFT { + + private static final Logger LOGGER = LoggerFactory.getLogger(TestFFT.class); + + public void checkSingleSineDouble(int size, int bin) { + double[] ar = new double[size]; + double[] ai = new double[size]; + double[] magnitudes = new double[size]; + + double amplitude = 1.0; + addSineWave(size, bin, ar, amplitude); + + FourierMath.transform(1, size, ar, ai); + FourierMath.calculateMagnitudes(ar, ai, magnitudes); + + assertEquals(0.0, magnitudes[bin-1], 0.000001, "magnitude"); + assertEquals(amplitude, magnitudes[bin], 0.000001, "magnitude"); + assertEquals(0.0, magnitudes[bin+1], 0.000001, "magnitude"); + /* + for (int i = 0; i < magnitudes.length; i++) { + System.out.printf("%d = %9.7f\n", i, magnitudes[i]); + } +*/ + + } + + public void checkSingleSineFloat(int size, int bin) { + float[] ar = new float[size]; + float[] ai = new float[size]; + float[] magnitudes = new float[size]; + + double amplitude = 1.0; + addSineWave(size, bin, ar, amplitude); + + FourierMath.transform(1, size, ar, ai); + FourierMath.calculateMagnitudes(ar, ai, magnitudes); + + assertEquals(0.0f, magnitudes[bin-1], 0.000001, "magnitude"); + assertEquals(amplitude, magnitudes[bin], 0.000001, "magnitude"); + assertEquals(0.0f, magnitudes[bin+1], 0.000001, "magnitude"); +/* + for (int i = 0; i < magnitudes.length; i++) { + System.out.printf("%d = %9.7f\n", i, magnitudes[i]); + } +*/ + } + + public void checkMultipleSine(int size, int[] bins, double[] amplitudes) { + double[] ar = new double[size]; + double[] ai = new double[size]; + double[] magnitudes = new double[size]; + + for(int i = 0; i<bins.length; i++) { + addSineWave(size, bins[i], ar, amplitudes[i]); + } + + FourierMath.transform(1, size, ar, ai); + FourierMath.calculateMagnitudes(ar, ai, magnitudes); + + for(int bin = 0; bin<size; bin++) { + System.out.printf("%d = %9.7f\n", bin, magnitudes[bin]); + + double amplitude = 0.0; + for(int i = 0; i<bins.length; i++) { + if ((bin == bins[i]) || (bin == (size - bins[i]))) { + amplitude = amplitudes[i]; + break; + } + } + assertEquals(amplitude, magnitudes[bin], 0.000001, "magnitude"); + } + + } + + private void addSineWave(int size, int bin, double[] ar, double amplitude) { + double phase = 0.0; + double phaseIncrement = 2.0 * Math.PI * bin / size; + for (int i = 0; i < size; i++) { + ar[i] += Math.sin(phase) * amplitude; + phase += phaseIncrement; + } + } + private void addSineWave(int size, int bin, float[] ar, double amplitude) { + double phase = 0.0; + double phaseIncrement = 2.0 * Math.PI * bin / size; + for (int i = 0; i < size; i++) { + ar[i] += (float) (Math.sin(phase) * amplitude); + phase += phaseIncrement; + } + } + + public void testSinglesDouble() { + checkSingleSineDouble(32, 1); + checkSingleSineDouble(32, 4); + checkSingleSineDouble(64, 5); + checkSingleSineDouble(256, 3); + } + + public void testSinglesFloat() { + checkSingleSineFloat(32, 1); + checkSingleSineFloat(32, 4); + checkSingleSineFloat(64, 5); + checkSingleSineFloat(256, 3); + } + + public void testMultipleSines32() { + int[] bins = { 1, 5 }; + double[] amplitudes = { 1.0, 2.0 }; + checkMultipleSine(32, bins, amplitudes); + } + + public void testMultipleSines64() { + int[] bins = { 2, 4, 7 }; + double[] amplitudes = { 1.0, 0.3, 0.5 }; + checkMultipleSine(64, bins, amplitudes); + } + + public void checkInverseFftDouble(int size, int bin) { + double[] ar1 = new double[size]; + double[] ai1 = new double[size]; + double[] ar2 = new double[size]; + double[] ai2 = new double[size]; + + double amplitude = 1.0; + addSineWave(size, bin, ar1, amplitude); + + // Save a copy of the source. + System.arraycopy(ar1, 0, ar2, 0, size); + System.arraycopy(ai1, 0, ai2, 0, size); + + FourierMath.transform(1, size, ar1, ai1); // FFT + + FourierMath.transform(-1, size, ar1, ai1); // IFFT + + for (int i = 0; i < size; i++) { + assertEquals(ar2[i], ar1[i], 0.00001); + assertEquals(ai2[i], ai1[i], 0.00001); + } + } + + public void checkInverseFftFloat(int size, int bin) { + float[] ar1 = new float[size]; + float[] ai1 = new float[size]; + float[] ar2 = new float[size]; + float[] ai2 = new float[size]; + + double amplitude = 1.0; + addSineWave(size, bin, ar1, amplitude); + + // Save a copy of the source. + System.arraycopy(ar1, 0, ar2, 0, size); + System.arraycopy(ai1, 0, ai2, 0, size); + + FourierMath.transform(1, size, ar1, ai1); // FFT + + FourierMath.transform(-1, size, ar1, ai1); // IFFT + + for (int i = 0; i < size; i++) { + assertEquals(ar2[i], ar1[i], 0.00001); + assertEquals(ai2[i], ai1[i], 0.00001); + } + } + + public void testInverseDouble() { + checkInverseFftDouble(32, 1); + checkInverseFftDouble(32, 2); + checkInverseFftDouble(128, 17); + checkInverseFftDouble(512, 23); + } + + public void testInverseFloat() { + checkInverseFftFloat(32, 1); + checkInverseFftFloat(32, 2); + checkInverseFftFloat(128, 17); + checkInverseFftFloat(512, 23); + } +} |