Micro Java Programs for JVM

最新推荐文章于 2025-02-08 15:44:08 发布

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CC 4.0 BY-SA版权

public class Main {
    public static void main(String[] args) {
        for(int i=0; i<100; i++)
            foo();
    }

    private static void foo() {
        for(int i=0; i<100; i++)
            bar();
    }

    private static void bar() {
    }
}

import java.lang.*;

class compile {

        synchronized public int inc() {
//        public int inc() {
             return 1;
        }

        public static void main (String args[]) {
                int sum = 0;
                compile test =new compile();
long startTime = System.currentTimeMillis();
             for(int i = 0; i <= 100; i++) {
                for(int j = 0; j < 10; j++) {
                   sum += test.inc();
                   sum += test.inc();
                   sum += test.inc();
                   sum += test.inc();
                   sum += test.inc();
                }
             }
long endTime = System.currentTimeMillis();
                System.err.println("sum = "+sum+" time: "+ (endTime - startTime));
        }
}

class compute{

    public final double execute(double omega, double G[][], int
            num_iterations) {
        int M = G.length;
        int N = G[0].length;

        double omega_over_four = omega * 0.25;
        double one_minus_omega = 1.0 - omega;
        double [] Gi = null;
        double Gi_Sum = 0.0;
        // update interior points
        //
        int Mm1 = M-1;
        int Nm1 = N-1;
        for (int p=0; p<num_iterations; p++) {
            for (int i=1; i<Mm1; i++) {
                Gi = G[i];
                double[] Gim1 = G[i-1];
                double[] Gip1 = G[i+1];
                for (int j=1; j<Nm1; j++)
                    Gi[j] = omega_over_four * (Gim1[j] + Gip1[j] + Gi[j-1]
                            + Gi[j+1]) + one_minus_omega * Gi[j];
            }
        }
        for(int k=0;k<Gi.length;k++)Gi_Sum += Gi[k];

        return Gi_Sum;
    }

   public static void main(String args[]) {
      compute test = new compute();
      double[][] G = new double[200][200];
      for(int i = 0; i < 200; i++) {
         for(int j = 0; j < 200; j++) {
            G[i][j] = 1.0 + i + j;
         }
      }
long startTime = System.currentTimeMillis();
      test.execute(2.0, G, 10000);
long endTime = System.currentTimeMillis();
System.err.println("time: "+ (endTime - startTime));
   }
}

class hello {

    public static void matmult(int x[][], int y[][], int z[][], int repeat) {
        int m = x.length;
        int k = x[0].length;
        int n = y[0].length;
for(int w = 0; w < repeat; w++) {
        for (int r = 0; r < m; r++) {
            for (int s = 0; s < n; s++) {
                z[r][s] = 0;
                for (int t = 0; t < k; t++) {
                    z[r][s] += x[r][t] * y[t][s];
                }
            }
        }
}
    }

    public static void main (String args[]) {
        int[][] x = {{3,3,3,3,3},{3,3,3,3,3},{3,3,3,3,3},{3,3,3,3,3},{3,3,3,3,3}};
        int[][] y = {{3,3,3,3,3},{3,3,3,3,3},{3,3,3,3,3},{3,3,3,3,3},{3,3,3,3,3}};
        int[][] z = {{0,0,0,0,0},{0,0,0,0,0},{0,0,0,0,0},{0,0,0,0,0},{0,0,0,0,0}};
long startTime = System.currentTimeMillis();
        hello.matmult(x, y, z, 900000);
long endTime = System.currentTimeMillis();
        System.err.println("time: "+ (endTime - startTime));
        }
}

class matrix {

    public static void matmult( int y[], int val[], int row[], int col[], int x[], int NUM_ITERATIONS) {
        int M = row.length - 1;
        for (int reps=0; reps<NUM_ITERATIONS; reps++) {

            for (int r=0; r<M; r++) {
                int sum = 0;
                int rowR = row[r];
                int rowRp1 = row[r+1];
                for (int i=rowR; i<rowRp1; i++) {
//                    sum += x[ col[i] ] * val[i];   //case 1
//                    sum += x[ col[i] ];            //case 2
                }
                y[r] = sum;
            }
        }
    }

    public static void main (String args[]) {
        int x[] = {12, 3, 6, 7, 2, 3, 3, 9, 10, 20, 10, 12, 11, 143, 18, 12, 12, 17, 14, 19, 12, 12, 12, 12, 12};
        int y[] = {12, 3, 6, 7, 2, 3, 3, 9, 10, 20, 10, 12, 11, 143, 18, 12, 12, 17, 14, 19, 12, 12, 12, 12, 12};
        int val[] = {12, 3, 6, 7, 2, 3, 3, 9, 10, 20, 10, 12, 11, 143, 18, 12, 12, 17, 14, 19, 12, 12, 12, 12, 12};
        int row[] = {8, 20, 4, 20, 4, 13, 20, 7, 12, 12, 14, 20, 20, 20, 8, 2, 3, 20, 5, 9, 12};
        int col[] = {8, 20, 4, 20, 4, 13, 20, 7, 12, 12, 14, 20, 20, 20, 8, 2, 3, 20, 5, 9, 12};
        double sum = 0.0;
long startTime = System.currentTimeMillis();
        matrix.matmult(y, val, row, col, x, 10000000);
long endTime = System.currentTimeMillis();
        System.err.println("sum = "+sum+" time: "+ (endTime - startTime));
        }
}

import java.lang.*;

class min {
        public min() {
        }

        synchronized public int inc() {
//        public int inc() {
             return 1;
        }

        public static void main (String args[]) {
                int sum = 0;
                min test =new min();
long startTime = System.currentTimeMillis();
             for(int i = 0; i <= 20000; i++) {
                for(int j = 0; j < 20000; j++) {
                   sum += test.inc();
/*
                   sum += test.inc();
                   sum += test.inc();
                   sum += test.inc();
                   sum += test.inc();
*/
                }
             }
long endTime = System.currentTimeMillis();
                System.err.println("sum = "+sum+" time: "+ (endTime - startTime));
        }
}

class sparse_small {

    public static void matmult( double y[], double val[], int row[], int col[], double x[], int NUM_ITERATIONS) {
        int M = row.length - 1;
        for (int reps=0; reps<NUM_ITERATIONS; reps++) {

            for (int r=0; r<M; r++) {
                double sum = 0.0;
                int rowR = row[r];
                int rowRp1 = row[r+1];
                for (int i=rowR; i<rowRp1; i++) {
                    sum += x[ col[i] ] * val[i];
                }
                y[r] = sum;
            }
        }
    }

    public static void main (String args[]) {
        double x[] = {12.0, 3.9, 6.7, 7.8, 2.9, 3.2, 3.7, 9.9, 10.1, 20.3, 10, 12.3, 11.1, 143, 18, 12.4, 12.2, 17, 14, 19, 12, 12, 12, 12, 12};
        double y[] = {12.0, 3.9, 6.7, 7.8, 2.9, 3.2, 3.7, 9.9, 10.1, 20.3, 10, 12.3, 11.1, 143, 18, 12.4, 12.2, 17, 14, 19, 12, 12, 12, 12, 12};
        double val[] = {12.0, 3.9, 6.7, 7.8, 2.9, 3.2, 3.7, 9.9, 10.1, 20.3, 10, 12.3, 11.1, 143, 18, 12.4, 12.2, 17, 14, 19, 12, 12, 12, 12, 12};
        int row[] = {8, 20, 4, 20, 4, 13, 20, 7, 12, 12, 14, 20, 20, 20, 8, 2, 3, 20, 5, 9, 12};
        int col[] = {8, 20, 4, 20, 4, 13, 20, 7, 12, 12, 14, 20, 20, 20, 8, 2, 3, 20, 5, 9, 12};
        double sum = 0.0;
long startTime = System.currentTimeMillis();
        sparse_small.matmult(y, val, row, col, x, 10000000);
long endTime = System.currentTimeMillis();
        System.err.println("sum = "+sum+" time: "+ (endTime - startTime));
        }
}

class sum {

    public static int cal(int low, int high) {
        int sum = 0;
        for (int i = low; i < high; i++) {
//            for (int j = -10; j < low; j++)
            sum += i;
        }
        return sum;
    }

    public static void main (String args[]) {
        int s = 0;
long startTime = System.currentTimeMillis();
//     for(int i = 0; i < 9999; i++)
        s = sum.cal(1, 900000);
long endTime = System.currentTimeMillis();
        System.err.println("s = "+s+"time: "+ (endTime - startTime));
        }
}