diff --git a/DIRECTORY.md b/DIRECTORY.md index d0de70715bbc..8d66f77d1ea9 100644 --- a/DIRECTORY.md +++ b/DIRECTORY.md @@ -938,6 +938,7 @@ * [CeilTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CeilTest.java) * [CollatzConjectureTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java) * [CombinationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CombinationsTest.java) + * [ConvolutionFFTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ConvolutionFFTTest.java) * [ConvolutionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ConvolutionTest.java) * [CrossCorrelationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CrossCorrelationTest.java) * [DeterminantOfMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DeterminantOfMatrixTest.java) diff --git a/src/main/java/com/thealgorithms/maths/FFT.java b/src/main/java/com/thealgorithms/maths/FFT.java index 47605f010b22..91754bd1a80b 100644 --- a/src/main/java/com/thealgorithms/maths/FFT.java +++ b/src/main/java/com/thealgorithms/maths/FFT.java @@ -165,6 +165,14 @@ public Complex divide(double n) { temp.img = this.img / n; return temp; } + + public double real() { + return real; + } + + public double imaginary() { + return img; + } } /** diff --git a/src/test/java/com/thealgorithms/maths/ConvolutionFFTTest.java b/src/test/java/com/thealgorithms/maths/ConvolutionFFTTest.java new file mode 100644 index 000000000000..4d627f939d42 --- /dev/null +++ b/src/test/java/com/thealgorithms/maths/ConvolutionFFTTest.java @@ -0,0 +1,55 @@ +package com.thealgorithms.maths; + +import static org.junit.jupiter.api.Assertions.assertEquals; + +import java.util.ArrayList; +import java.util.List; +import java.util.stream.Stream; +import org.junit.jupiter.params.ParameterizedTest; +import org.junit.jupiter.params.provider.Arguments; +import org.junit.jupiter.params.provider.MethodSource; + +public class ConvolutionFFTTest { + + /** + * Helper method to create a complex signal from an array of doubles. + */ + private ArrayList createComplexSignal(double[] values) { + ArrayList signal = new ArrayList<>(); + for (double value : values) { + signal.add(new FFT.Complex(value, 0)); + } + return signal; + } + + /** + * Helper method to compare two complex signals for equality within a small margin of error. + */ + private void assertComplexArrayEquals(List expected, List result, double delta) { + assertEquals(expected.size(), result.size(), "Signal lengths are not equal."); + for (int i = 0; i < expected.size(); i++) { + FFT.Complex expectedValue = expected.get(i); + FFT.Complex resultValue = result.get(i); + assertEquals(expectedValue.real(), resultValue.real(), delta, "Real part mismatch at index " + i); + assertEquals(expectedValue.imaginary(), resultValue.imaginary(), delta, "Imaginary part mismatch at index " + i); + } + } + + @ParameterizedTest(name = "Test case {index}: {3}") + @MethodSource("provideTestCases") + public void testConvolutionFFT(double[] a, double[] b, double[] expectedOutput, String testDescription) { + ArrayList signalA = createComplexSignal(a); + ArrayList signalB = createComplexSignal(b); + + ArrayList expected = createComplexSignal(expectedOutput); + ArrayList result = ConvolutionFFT.convolutionFFT(signalA, signalB); + + assertComplexArrayEquals(expected, result, 1e-9); // Allow small margin of error + } + + private static Stream provideTestCases() { + return Stream.of(Arguments.of(new double[] {1, 2, 3}, new double[] {4, 5, 6}, new double[] {4, 13, 28, 27, 18}, "Basic test"), Arguments.of(new double[] {0, 0, 0}, new double[] {1, 2, 3}, new double[] {0, 0, 0, 0, 0}, "Test with zero elements"), + Arguments.of(new double[] {1, 2}, new double[] {3, 4, 5}, new double[] {3, 10, 13, 10}, "Test with different sizes"), Arguments.of(new double[] {5}, new double[] {2}, new double[] {10}, "Test with single element"), + Arguments.of(new double[] {1, -2, 3}, new double[] {-1, 2, -3}, new double[] {-1, 4, -10, 12, -9}, "Test with negative values")); + } +}