feat: Add Chebyshev Iteration algorithm (#6963)

* feat: Add Chebyshev Iteration algorithm * Update ChebyshevIteration.java * Update ChebyshevIterationTest.java * Update ChebyshevIteration.java * Update ChebyshevIterationTest.java * Update ChebyshevIteration.java * Update ChebyshevIteration.java * Update ChebyshevIterationTest.java * Update ChebyshevIteration.java * Update ChebyshevIterationTest.java * Update ChebyshevIterationTest.java * Update ChebyshevIteration.java * Update ChebyshevIteration.java * Update ChebyshevIterationTest.java * Update ChebyshevIteration.java * Update ChebyshevIterationTest.java * Update ChebyshevIteration.java * Update ChebyshevIterationTest.java * update * Update ChebyshevIteration.java * Update ChebyshevIterationTest.java * Update ChebyshevIteration.java * Update ChebyshevIterationTest.java * Update ChebyshevIteration.java * Update ChebyshevIterationTest.java
2025-12-19 07:00:35 +08:00 · 2025-10-28 21:13:54 +05:30
parent 3c70a54355
commit 68746f880f
2 changed files with 286 additions and 0 deletions
--- a/src/test/java/com/thealgorithms/maths/ChebyshevIterationTest.java
+++ b/src/test/java/com/thealgorithms/maths/ChebyshevIterationTest.java
@@ -0,0 +1,105 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class ChebyshevIterationTest {
+
+    @Test
+    public void testSolveSimple2x2Diagonal() {
+        double[][] a = {{2, 0}, {0, 1}};
+        double[] b = {2, 2};
+        double[] x0 = {0, 0};
+        double minEig = 1.0;
+        double maxEig = 2.0;
+        int maxIter = 50;
+        double tol = 1e-9;
+        double[] expected = {1.0, 2.0};
+
+        double[] result = ChebyshevIteration.solve(a, b, x0, minEig, maxEig, maxIter, tol);
+        assertArrayEquals(expected, result, 1e-9);
+    }
+
+    @Test
+    public void testSolve2x2Symmetric() {
+        double[][] a = {{4, 1}, {1, 3}};
+        double[] b = {1, 2};
+        double[] x0 = {0, 0};
+        double minEig = (7.0 - Math.sqrt(5.0)) / 2.0;
+        double maxEig = (7.0 + Math.sqrt(5.0)) / 2.0;
+        int maxIter = 100;
+        double tol = 1e-10;
+        double[] expected = {1.0 / 11.0, 7.0 / 11.0};
+
+        double[] result = ChebyshevIteration.solve(a, b, x0, minEig, maxEig, maxIter, tol);
+        assertArrayEquals(expected, result, 1e-9);
+    }
+
+    @Test
+    public void testAlreadyAtSolution() {
+        double[][] a = {{2, 0}, {0, 1}};
+        double[] b = {2, 2};
+        double[] x0 = {1, 2};
+        double minEig = 1.0;
+        double maxEig = 2.0;
+        int maxIter = 10;
+        double tol = 1e-5;
+        double[] expected = {1.0, 2.0};
+
+        double[] result = ChebyshevIteration.solve(a, b, x0, minEig, maxEig, maxIter, tol);
+        assertArrayEquals(expected, result, 0.0);
+    }
+
+    @Test
+    public void testMismatchedDimensionsAB() {
+        double[][] a = {{1, 0}, {0, 1}};
+        double[] b = {1};
+        double[] x0 = {0, 0};
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, 1, 2, 10, 1e-5));
+    }
+
+    @Test
+    public void testMismatchedDimensionsAX() {
+        double[][] a = {{1, 0}, {0, 1}};
+        double[] b = {1, 1};
+        double[] x0 = {0};
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, 1, 2, 10, 1e-5));
+    }
+
+    @Test
+    public void testNonSquareMatrix() {
+        double[][] a = {{1, 0, 0}, {0, 1, 0}};
+        double[] b = {1, 1};
+        double[] x0 = {0, 0};
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, 1, 2, 10, 1e-5));
+    }
+
+    @Test
+    public void testInvalidEigenvalues() {
+        double[][] a = {{1, 0}, {0, 1}};
+        double[] b = {1, 1};
+        double[] x0 = {0, 0};
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, 2, 1, 10, 1e-5));
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, 1, 1, 10, 1e-5));
+    }
+
+    @Test
+    public void testNonPositiveDefinite() {
+        double[][] a = {{1, 0}, {0, 1}};
+        double[] b = {1, 1};
+        double[] x0 = {0, 0};
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, 0, 1, 10, 1e-5));
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, -1, 1, 10, 1e-5));
+    }
+
+    @Test
+    public void testInvalidIterationCount() {
+        double[][] a = {{1, 0}, {0, 1}};
+        double[] b = {1, 1};
+        double[] x0 = {0, 0};
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, 1, 2, 0, 1e-5));
+        assertThrows(IllegalArgumentException.class, () -> ChebyshevIteration.solve(a, b, x0, 1, 2, -1, 1e-5));
+    }
+}