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copied!<p>class Quad implements Runnable{ //Shared Variables static volatile double [][] stack; static volatile boolean first=true; static Object lock1; static Object lock2; static double FinalResult; static AtomicInteger threadCounter; static AtomicInteger stackpointer; static int nthreads; //Constants static final int stacksize = 1000; static final int il = 0; static final int ir = 1; static final int ie = 2; static final int dims = 3; //Private Variables int tid; double left,right,eps;</p> <pre><code>private double result; private double l,r,ep; private boolean calculate; public Quad(double left, double right, double eps,int tid,int nthreads) { this.left = left; this.right = right; this.eps = eps; this.tid = tid; Quad.nthreads = nthreads; result = 0.0; synchronized(this){ //Only the first thread will do it if(first==true){ first=false; lock1 = new Object(); lock2 = new Object(); stack = new double [dims][stacksize]; threadCounter= new AtomicInteger(0); stackpointer = new AtomicInteger(1); stack[il][stackpointer.get()] = left; stack[ir][stackpointer.get()] = right; stack[ie][stackpointer.get()] = eps; FinalResult=0.0; System.out.println("I am tid= "+tid ); } } } public void run(){ stackops(); add(); } public void stackops() { double abserror,m, est1, est2; est2=est1=m=abserror=0; while ((stackpointer.get() >= 1)|| threadCounter.get()>0) { // Pop next interval off stack. synchronized (lock1){ pop(); } // Compute estimates. if (calculate == true){ m = 0.5 * (l + r); est1 = 0.5 * (r - l) * (func(l) + func(r)) ; est2 = 0.5 * ((m - l) * (func(l) + func(m)) + (r - m) * (func(m) + func(r))); abserror = Math.abs(est2-est1) / 3.0; if (abserror <= ep) { result += est2; } else { //Push into the stack synchronized (lock1){ push(m); } }//end else threadCounter.decrementAndGet(); } }//end while System.out.println("I am " + tid+" result = "+result); }//end method private void add(){ synchronized(lock1){ FinalResult +=result; } } private void pop(){ if(stackpointer.get()>0){ threadCounter.incrementAndGet(); calculate =true; l = stack[il][stackpointer.get()]; r = stack[ir][stackpointer.get()]; ep = stack[ie][stackpointer.get()]; stackpointer.decrementAndGet(); }else{ calculate =false; } } private void push (double m){ if(stackpointer.get()>=-1){ stackpointer.incrementAndGet(); stack[il][stackpointer.get()] = l; stack[ir][stackpointer.get()] = m; stack[ie][stackpointer.get()] = ep * 0.5; stackpointer.incrementAndGet(); stack[il][stackpointer.get()] = m; stack[ir][stackpointer.get()] = r; stack[ie][stackpointer.get()] = ep * 0.5; } } public double getResult(){ return FinalResult; } private double func(double x) { double q; int n; n = 10000; q = 1000.0; for(int i=0;i<n;i++) { q -= x; } if (q == 1.0e10) System.out.println("q = " + q); return x * x; } </code></pre> <p>}</p>

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