DAS_2023_1/martysheva_tamara_lab_6/myapp/Main.java

<EFBFBD><EFBFBD>import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.*;

public class Main {
    public static void main(String[] args) throws InterruptedException {
        int nThreads = 8;
        //100x100
        var matrix = Matrix(6);
        //>A;54>20B5;L=K9 0;3>@8B<
        long startTime = System.currentTimeMillis();
        int determinant = SequentialDeterminant(matrix, matrix.length);
        long endTime = System.currentTimeMillis();
        System.out.println(">A;54>20B5;L=>, 6x6, 2@5<O 2K?>;=5=8O: " + (endTime - startTime) + " <8;;8A5:C=4");
        //0@0;;5;L=K9 0;3>@8B<
        startTime = System.currentTimeMillis();
        determinant = ParallelDeterminant(matrix, matrix.length, nThreads);
        endTime = System.currentTimeMillis();
        System.out.println("0@0;;5;L=>, 6x6, (" + nThreads + " ?>B>:>2), 2@5<O 2K?>;=5=8O : " + (endTime - startTime) + " <8;;8A5:C=4\n");

        //300x300
        matrix = Matrix(9);
        //>A;54>20B5;L=K9 0;3>@8B<
        startTime = System.currentTimeMillis();
        determinant = SequentialDeterminant(matrix, matrix.length);
        endTime = System.currentTimeMillis();
        System.out.println(">A;54>20B5;L=>, 9x9, 2@5<O 2K?>;=5=8O: " + (endTime - startTime) + " <8;;8A5:C=4");
        //0@0;;5;L=K9 0;3>@8B<
        startTime = System.currentTimeMillis();
        determinant = ParallelDeterminant(matrix, matrix.length, nThreads);
        endTime = System.currentTimeMillis();
        System.out.println("0@0;;5;L=>, 9x9, (" + nThreads + " ?>B>:>2), 2@5<O 2K?>;=5=8O : " + (endTime - startTime) + " <8;;8A5:C=4\n");

        //500x500
        matrix = Matrix(12);
        //>A;54>20B5;L=K9 0;3>@8B<
        startTime = System.currentTimeMillis();
        determinant = SequentialDeterminant(matrix, matrix.length);
        endTime = System.currentTimeMillis();
        System.out.println(">A;54>20B5;L=>, 12x12, 2@5<O 2K?>;=5=8O: " + (endTime - startTime) + " <8;;8A5:C=4");
        //0@0;;5;L=K9 0;3>@8B<
        startTime = System.currentTimeMillis();
        determinant = ParallelDeterminant(matrix, matrix.length, nThreads);
        endTime = System.currentTimeMillis();
        System.out.println("0@0;;5;L=>, 12x12, (" + nThreads + " ?>B>:>2), 2@5<O 2K?>;=5=8O : " + (endTime - startTime) + " <8;;8A5:C=4\n");
    }

    public static int[][] Matrix(int size) {
        int[][] matrix = new int[size][size];
        for (int i = 0; i < size; i++) {
            for (int j = 0; j < size; j++) {
                matrix[i][j] = (int) (Math.random() * 1000);
            }
        }
        return matrix;
    }

    public static int SequentialDeterminant(int[][] matrix, int size) {
        if (size == 1) {
            return matrix[0][0];
        }
        else if (size == 2) {
            return matrix[0][0] * matrix[1][1] - matrix[0][1] * matrix[1][0];
        }
        else {
            int det = 0;
            for (int i = 0; i < size; i++) {
                var submatrix = Submatrix(matrix, i);
                det += Math.pow(-1, i) * matrix[0][i] * SequentialDeterminant(submatrix, submatrix.length);
            }
            return det;
        }
    }

    private static int[][] Submatrix(int[][] matrix, int excludeCol) {
        int size = matrix.length - 1;
        int[][] submatrix = new int[size][size];

        int rowIndex = 0;
        for (int i = 0; i < matrix.length; i++) {
            if (i == 0) {
                continue;
            }
            int colIndex = 0;
            for (int j = 0; j < matrix[i].length; j++) {
                if (j == excludeCol) {
                    continue;
                }
                submatrix[rowIndex][colIndex] = matrix[i][j];
                colIndex++;
            }
            rowIndex++;
        }
        return submatrix;
    }

    public static int ParallelDeterminant(int[][] matrix, int size, int threads) {
        if (size == 1) {
            return matrix[0][0];
        }
        else if (size == 2) {
            return matrix[0][0] * matrix[1][1] - matrix[0][1] * matrix[1][0];
        }
        else {
            int det = 0;
            ExecutorService executor = Executors.newFixedThreadPool(threads);
            List<Callable<Integer>> tasks = new ArrayList<>();

            for (int i = 0; i < size; i++) {
                var submatrix = Submatrix(matrix, i);
                int finalI = i;
                tasks.add(() -> (int) Math.pow(-1, finalI) * matrix[0][finalI] * SequentialDeterminant(submatrix, submatrix.length));
            }

            try {
                List<Future<Integer>> futures = executor.invokeAll(tasks);
                for (Future<Integer> future : futures) {
                    det += future.get();
                }
            } catch (InterruptedException | ExecutionException e) {
                e.printStackTrace();
                return -1;
            } finally {
                executor.shutdown();
            }

            return det;
        }
    }
}