Merge pull request #110 from acsolle66/feature-matrix-vector-product

feat(#101): implement MatrixVectorProduct
Samyssmile · Nov 9, 2023 · 2e43d6f · 2e43d6f
2 parents 34562ac + ad93c9a
commit 2e43d6f
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Showing 5 changed files with 101 additions and 34 deletions.
diff --git a/...ple/src/main/java/de/example/decisiontree/DecisionTreeExampleOnPenguinsDatasetNoHead.java b/...ple/src/main/java/de/example/decisiontree/DecisionTreeExampleOnPenguinsDatasetNoHead.java
@@ -18,7 +18,7 @@ public class DecisionTreeExampleOnPenguinsDatasetNoHead {
               + "seaborn-penguins"
               + File.separator
               + "penguins-no-head.csv");
-  private static final boolean SKIP_HEAD = true;
+  private static final boolean SKIP_HEAD = false;
   private static final ImputationStrategy averageImputation = ImputationStrategy.AVERAGE;
   private static final ImputationStrategy modeImputation = ImputationStrategy.MODE;
 

diff --git a/lib/src/main/java/de/edux/core/math/matrix/parallel/MatrixArithmetic.java b/lib/src/main/java/de/edux/core/math/matrix/parallel/MatrixArithmetic.java
@@ -18,11 +18,30 @@ public MatrixArithmetic() {
 
   @Override
   public double[][] multiply(double[][] matrixA, double[][] matrixB) {
+
+    if (matrixA == null || matrixB == null) {
+      throw new IllegalArgumentException("Matrices must not be null.");
+    }
+    if (matrixA.length == 0 || matrixB.length == 0) {
+      throw new IllegalArgumentException("Matrices must not be empty.");
+    }
+    if (matrixA[0].length != matrixB.length) {
+      throw new IllegalArgumentException("Matrix A columns must match Matrix B rows.");
+    }
+
     return matrixProduct.multiply(matrixA, matrixB);
   }
 
   @Override
   public double[] multiply(double[][] matrix, double[] vector) {
+
+    if (matrix.length == 0 || matrix[0].length == 0 || vector.length == 0) {
+      throw new IllegalArgumentException("Matrix and vector must not be empty.");
+    }
+    if (matrix[0].length != vector.length) {
+      throw new IllegalArgumentException("Matrix columns and vector size do not match.");
+    }
+
     return matrixVectorProduct.multiply(matrix, vector);
   }
 }
diff --git a/lib/src/main/java/de/edux/core/math/matrix/parallel/operations/MatrixProduct.java b/lib/src/main/java/de/edux/core/math/matrix/parallel/operations/MatrixProduct.java
@@ -1,30 +1,17 @@
 package de.edux.core.math.matrix.parallel.operations;
 
 import de.edux.core.math.IMatrixProduct;
-
 import java.util.stream.IntStream;
 
 public class MatrixProduct implements IMatrixProduct {
 
-  private void checkSizeForMultiplication(double[][] matrixA, double[][] matrixB) {
-    int m = matrixB.length;
-    int n = matrixA[0].length;
-    if (m != n) {
-      throw new RuntimeException(
-          "\"The number of columns in the first matrix must be equal to the number of rows in the second matrix.\"");
-    }
-  }
-
   @Override
   public double[][] multiply(double[][] matrixA, double[][] matrixB) {
-    checkSizeForMultiplication(matrixA, matrixB);
-
     int aRows = matrixA.length;
     int aColumns = matrixA[0].length;
     int bColumns = matrixB[0].length;
 
     double[][] result = new double[aRows][bColumns];
-
     IntStream.range(0, aRows)
         .parallel()
         .forEach(

diff --git a/lib/src/main/java/de/edux/core/math/matrix/parallel/operations/MatrixVectorProduct.java b/lib/src/main/java/de/edux/core/math/matrix/parallel/operations/MatrixVectorProduct.java
@@ -1,10 +1,25 @@
 package de.edux.core.math.matrix.parallel.operations;
 
 import de.edux.core.math.IMatrixVectorProduct;
+import java.util.stream.IntStream;
 
 public class MatrixVectorProduct implements IMatrixVectorProduct {
+
   @Override
   public double[] multiply(double[][] matrix, double[] vector) {
-    return new double[0];
+    int matrixRows = matrix.length;
+    int matrixColumns = matrix[0].length;
+
+    double[] result = new double[matrixRows];
+    IntStream.range(0, matrixRows)
+        .parallel()
+        .forEach(
+            row -> {
+              for (int col = 0; col < matrixColumns; col++) {
+                result[row] += matrix[row][col] * vector[col];
+              }
+            });
+
+    return result;
   }
 }
diff --git a/lib/src/test/java/de/edux/core/math/matrix/parallel/MatrixArithmeticTest.java b/lib/src/test/java/de/edux/core/math/matrix/parallel/MatrixArithmeticTest.java
@@ -2,11 +2,18 @@
 
 import static org.junit.jupiter.api.Assertions.*;
 
-import de.edux.core.math.IMatrixArithmetic;
+import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 
 class MatrixArithmeticTest {
 
+  private static MatrixArithmetic matrixArithmetic;
+
+  @BeforeAll
+  static void setUp() {
+    matrixArithmetic = new MatrixArithmetic();
+  }
+
   @Test
   public void testLargeMatrixMultiplication() {
     int matrixSize = 200;
@@ -19,8 +26,8 @@ public void testLargeMatrixMultiplication() {
         matrixB[i][j] = 1;
       }
     }
-    IMatrixArithmetic matrixParallelArithmetic = new MatrixArithmetic();
-    double[][] result = matrixParallelArithmetic.multiply(matrixA, matrixB);
+
+    double[][] result = matrixArithmetic.multiply(matrixA, matrixB);
     for (int i = 0; i < matrixSize; i++) {
       for (int j = 0; j < matrixSize; j++) {
         assertEquals(matrixSize, result[i][j], "Result on [" + i + "][" + j + "] not correct.");
@@ -45,15 +52,13 @@ public void shouldThrowRuntimeExceptionForMatricesWithIncompatibleSizes() {
       {-1, 6},
     };
 
-    IMatrixArithmetic matrixParallelArithmetic = new MatrixArithmetic();
-
     assertAll(
         () ->
             assertThrows(
-                RuntimeException.class, () -> matrixParallelArithmetic.multiply(matrixA, matrixB)),
+                RuntimeException.class, () -> matrixArithmetic.multiply(matrixA, matrixB)),
         () ->
             assertThrows(
-                RuntimeException.class, () -> matrixParallelArithmetic.multiply(matrixC, matrixA)));
+                RuntimeException.class, () -> matrixArithmetic.multiply(matrixC, matrixA)));
   }
 
   @Test
@@ -89,9 +94,7 @@ public void shouldMultiply8x8MatricesCorrectly() {
       {22, 18, 14, 10, 22, 18, 14, 10}
     };
 
-    IMatrixArithmetic matrixParallelArithmetic = new MatrixArithmetic();
-    double[][] result = matrixParallelArithmetic.multiply(matrixA, matrixB);
-
+    double[][] result = matrixArithmetic.multiply(matrixA, matrixB);
     assertArrayEquals(
         expected, result, "The 8x8 matrix multiplication did not yield the correct result.");
   }
@@ -111,9 +114,7 @@ public void shouldMultiplyWithZeroMatrix() {
       {0, 0}
     };
 
-    IMatrixArithmetic matrixParallelArithmetic = new MatrixArithmetic();
-    double[][] result = matrixParallelArithmetic.multiply(matrixA, matrixB);
-
+    double[][] result = matrixArithmetic.multiply(matrixA, matrixB);
     assertArrayEquals(expected, result);
   }
 
@@ -128,9 +129,7 @@ public void shouldMultiplyWithIdentityMatrix() {
       {7, 8}
     };
 
-    IMatrixArithmetic matrixParallelArithmetic = new MatrixArithmetic();
-    double[][] result = matrixParallelArithmetic.multiply(matrixA, matrixB);
-
+    double[][] result = matrixArithmetic.multiply(matrixA, matrixB);
     assertArrayEquals(matrixB, result);
   }
 
@@ -149,9 +148,56 @@ public void shouldMultiplySmallMatricesCorrectly() {
       {10, 8}
     };
 
-    IMatrixArithmetic matrixParallelArithmetic = new MatrixArithmetic();
-    double[][] result = matrixParallelArithmetic.multiply(matrixA, matrixB);
-
+    double[][] result = matrixArithmetic.multiply(matrixA, matrixB);
     assertArrayEquals(expected, result);
   }
+
+  @Test
+  void shouldSolveMatrixVectorProduct() {
+    int matrixSize = 2048;
+    double[][] matrixA = new double[matrixSize][matrixSize];
+    double[] vector = new double[matrixSize];
+
+    for (int i = 0; i < matrixSize; i++) {
+      for (int j = 0; j < matrixSize; j++) {
+        matrixA[i][j] = 1;
+        vector[i] = 1;
+      }
+    }
+
+    double[] resultVector = matrixArithmetic.multiply(matrixA, vector);
+    for (int i = 0; i < matrixSize; i++) {
+      assertEquals(matrixSize, resultVector[i], "Result on [" + i + "][" + i + "] not correct.");
+    }
+  }
+
+  @Test
+  void shouldHandleEmptyMatrix() {
+    double[][] matrix = new double[0][0];
+    double[] vector = new double[0];
+    assertThrows(IllegalArgumentException.class, () -> matrixArithmetic.multiply(matrix, vector));
+  }
+
+  @Test
+  void shouldHandleMismatchedSizes() {
+    double[][] matrix = {{1, 2, 3}, {4, 5, 6}};
+    double[] vector = {1, 2};
+    assertThrows(IllegalArgumentException.class, () -> matrixArithmetic.multiply(matrix, vector));
+  }
+
+  @Test
+  void shouldHandleNullMatrix() {
+    double[] vector = {1, 2, 3};
+    assertThrows(NullPointerException.class, () -> matrixArithmetic.multiply(null, vector));
+  }
+
+  @Test
+  void shouldMultiplyVectorWithIdentityMatrix() {
+    double[][] matrix = {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}};
+    double[] vector = {1, 2, 3};
+    double[] expected = {1, 2, 3};
+    double[] result = matrixArithmetic.multiply(matrix, vector);
+    assertArrayEquals(
+      expected, result, "Multiplying with identity matrix should return the original vector.");
+  }
 }