tepechin_kirill_lab_5/src/MatrixMultiply.java

@@ -0,0 +1,81 @@
+import java.util.Arrays;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+public class MatrixMultiply {
+
+    public static int[][] generateMatrix(int n) {
+        int[][] matrix = new int[n][n];
+
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < n; j++) {
+                matrix[i][j] = (int) (Math.random() * 100);
+            }
+        }
+
+        return matrix;
+    }
+
+
+    private static int calculateSingleValue(int i, int j, int[][] a, int[][] b) {
+        int result = 0;
+        for (int k = 0; k < a[0].length; ++k) {
+            result += a[i][k] * b[k][j];
+        }
+        return result;
+    }
+
+
+    public static int[][] multiplySync(int[][] a, int[][] b) {
+        final int[][] result = new int[a.length][b[0].length];
+        for (int i = 0; i < a.length; ++i) {
+            for (int j = 0; j < b[0].length; ++j) {
+                result[i][j] = calculateSingleValue(i, j, a, b);
+            }
+        }
+        return result;
+    }
+
+    public static int[][] multiplyAsync(int[][] a, int[][] b, ExecutorService executor) throws InterruptedException {
+        final int[][] result = new int[a.length][b[0].length];
+        for (int i = 0; i < a.length; ++i) {
+            final int fi = i;
+            executor.execute(() -> {
+                for (int j = 0; j < b[0].length; ++j) {
+                    for (int k = 0; k < a[0].length; ++k) {
+                        result[fi][j] += a[fi][k] * b[k][j];
+                    }
+                }
+            });
+        }
+        executor.shutdown();
+        executor.awaitTermination(1, TimeUnit.DAYS);
+        return result;
+    }
+
+    public static void main(String[] args) throws InterruptedException {
+        run(100);
+        run(300);
+        run(500);
+    }
+
+    public static void run(int n) throws InterruptedException {
+        System.out.println("N = " + n);
+        final ExecutorService executorService = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());
+
+        final int[][] a = generateMatrix(n);
+        final int[][] b = generateMatrix(n);
+
+        long time = System.currentTimeMillis();
+        final int[][] productSync = multiplySync(a, b);
+        System.out.println("Time sync: " + (System.currentTimeMillis() - time));
+
+        time = System.currentTimeMillis();
+        final int[][] productAsync = multiplyAsync(a, b, executorService);
+        System.out.println("Time async: " + (System.currentTimeMillis() - time));
+        System.out.println();
+
+//        System.out.println(Arrays.deepEquals(productAsync, productSync));
+    }
+}