initial commit

task1/Main.java

+
+package Task1;
+
+import java.util.*;
+
+public class Main {
+
+
+  // random matrices
+  public static double[][] generate(int rows, int columns) {
+    double[][] ret = new double[rows][columns];
+    Random random = new Random();
+    for (int i = 0; i < rows; i++)
+      for (int j = 0; j < columns; j++)
+        ret[i][j] = random.nextDouble() * 10;
+    return ret;
+  }
+
+  public static void main(String[] args) {
+
+    final int size = 1000;
+    double[][] matrix1 = generate(size, size);
+    double[][] matrix2 = generate(size, size);
+    double[][] result = new double[matrix1.length][matrix2[0].length];
+
+    System.out.println("Serial version running...");
+    Date start = new Date();
+    SerialMult.multiply(matrix1, matrix2, result);
+    Date end = new Date();
+    System.out.println("Serial Multiplication: " + (end.getTime() - start.getTime()) + "ms");
+
+    System.out.println("Parallel version by row running...");
+    start = new Date();
+    MatrixMult.multiply(matrix1, matrix2, result);
+    end = new Date();
+    System.out.println("Parallel Row: "+ (end.getTime() - start.getTime()) + "ms");
+  }
+}

task1/MatrixMult.java

+
+package Task1;
+
+import java.util.*;
+
+public class MatrixMult {
+
+    public static void multiply(double[][] A, double[][] B, double[][] C) {
+        List<Thread> threads = new ArrayList<>();
+        for (int i = 0; i < A.length; i++) {
+            RowMultiplierTask task = new RowMultiplierTask(C, A, B, i);
+            Thread thread = new Thread(task);
+
+
+
+
+            // TODO: your solution here
+
+
+
+
+
+            if (threads.size() % 10 == 0) { waitForThreads(threads); }
+        }
+        if (!threads.isEmpty()) { waitForThreads(threads); }
+    }
+
+    private static void waitForThreads(List<Thread> threads) {
+        for (Thread thread : threads) {
+            try {
+
+
+
+
+
+                // TODO: your solution here
+
+
+
+
+                
+            }
+            catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+        threads.clear();
+    }
+}
+
+

task1/RowMultiplierTask.java

+
+package Task1;
+
+public class RowMultiplierTask implements Runnable {
+
+    private final double[][] C, A, B;
+    private final int row;
+
+    public RowMultiplierTask(double[][] C, double[][] A, double[][] B, int i) {
+        this.C = C;
+
+        this.A = A;
+        this.B = B;
+
+        this.row = i;
+    }
+
+    public void run() {
+        for (int j = 0; j < B[0].length; j++) {
+            C[row][j] = 0;
+            for (int k = 0; k < A[row].length; k++)
+                C[row][j] += A[row][k] * B[k][j];
+        } // for j
+    }
+}

task1/SerialMult.java

+
+package Task1;
+
+public class SerialMult {
+    public static void multiply(double[][] A, double[][] B, double[][] C) {
+        int m = A.length;
+        int n = A[0].length;
+        int k = B[0].length;
+        for (int I = 0; I < m; I++)
+            for (int J = 0; J < k; J++) {
+                C[I][J] = 0;
+                for (int K = 0; K < n; K++)
+                    C[I][J] += A[I][K] * B[K][J];
+            } // for J
+    }
+}
+