From b9fac81ac0cdf317781d419149225a525c4c630e Mon Sep 17 00:00:00 2001
From: Matthew Ellison <m_ellison@ymail.com>
Date: Mon, 7 Feb 2022 19:30:03 +0000
Subject: [PATCH] Added adjoint and inverse functions

---
 .../mattrixwv/matrix/TestIntegerMatrix.java   | 94 +++++++++++++++++++
 1 file changed, 94 insertions(+)

diff --git a/src/test/java/com/mattrixwv/matrix/TestIntegerMatrix.java b/src/test/java/com/mattrixwv/matrix/TestIntegerMatrix.java
index 7b64c0a..5b78031 100644
--- a/src/test/java/com/mattrixwv/matrix/TestIntegerMatrix.java
+++ b/src/test/java/com/mattrixwv/matrix/TestIntegerMatrix.java
@@ -1238,4 +1238,98 @@ public class TestIntegerMatrix{
 			{2475, 4950, 7425, 9900, 12375, 14850, 17325, 19800, 22275, 24750}
 		});
 	}
+
+	@Test
+	public void testAdjoint(){
+		//1x1
+		IntegerMatrix matrix = new IntegerMatrix(grid1);
+		IntegerMatrix correctMatrix = new IntegerMatrix(grid1);
+		assertEquals("IntegerMatrix 1x1 failed adjoint", correctMatrix, matrix.adjoint());
+
+		//2x2
+		matrix = new IntegerMatrix(grid2);
+		correctMatrix = new IntegerMatrix(new int[][]{
+			{2, -2},
+			{-1, 1}
+		});
+		assertEquals("IntegerMatrix 2x2 failed adjoint", correctMatrix, matrix.adjoint());
+
+		//3x3
+		matrix = new IntegerMatrix(grid3);
+		correctMatrix = new IntegerMatrix(3, 3, 0);
+		assertEquals("IntegerMatrix 3x3 failed adjoint", correctMatrix, matrix.adjoint());
+
+		//4x4
+		matrix = new IntegerMatrix(new int[][]{
+			{1, 2, 3, 4},
+			{2, 3, 4, 1},
+			{3, 4, 1, 2},
+			{4, 1, 2, 3}
+		});
+		correctMatrix = new IntegerMatrix(new int[][]{
+			{-36, 4, 4, 44},
+			{4, 4, 44, -36},
+			{4, 44, -36, 4},
+			{44, -36, 4, 4}
+		});
+		assertEquals("IntegerMatrix 4x4 failed adjoint", correctMatrix, matrix.adjoint());
+
+		//10x10
+		//?Skipping 10x10 test because test took > 5s by itself
+		/*
+		matrix = new IntegerMatrix(grid10);
+		correctMatrix = new IntegerMatrix(10, 10, 0);
+		assertEquals("IntegerMatrix 10x10 failed adjoint", correctMatrix, matrix.adjoint());
+		*/
+	}
+
+	@Test
+	public void testInverse(){
+		//1x1
+		IntegerMatrix matrix = new IntegerMatrix(grid1);
+		IntegerMatrix correctMatrix = new IntegerMatrix(grid1);
+		assertEquals("IntegerMatrix 1x1 failed inverse", correctMatrix, matrix.inverse());
+
+		//2x2
+		matrix = new IntegerMatrix(new int[][]{
+			{1, 4},
+			{4, 1}
+		});
+		correctMatrix = new IntegerMatrix(new int[][]{
+			{-0, 0},
+			{0, -0}
+		});
+		assertEquals("IntegerMatrix 2x2 failed inverse", correctMatrix, matrix.inverse());
+
+		//3x3
+		matrix = new IntegerMatrix(new int[][]{
+			{1, 4, 2},
+			{2, 4, 1},
+			{4, 1, 2}
+		});
+		correctMatrix = new IntegerMatrix(new int[][]{
+			{-0, 0, 0},
+			{0, 0, -0},
+			{0, -0, 0}
+		});
+		assertEquals("IntegerMatrix 3x3 failed inverse", correctMatrix, matrix.inverse());
+
+		//4x4
+		matrix = new IntegerMatrix(new int[][]{
+			{1, 2, 3, 4},
+			{2, 3, 4, 1},
+			{3, 4, 1, 2},
+			{4, 1, 2, 3}
+		});
+		correctMatrix = new IntegerMatrix(new int[][]{
+			{-0, 0, 0, 0},
+			{0, 0, 0, -0},
+			{0, 0, -0, 0},
+			{0, -0, 0, 0}
+		});
+		assertEquals("IntegerMatrix 4x4 failed inverse", correctMatrix, matrix.inverse());
+
+		//10x10
+		//?Skipped 10x10 because it would take a long time to compute
+	}
 }