/**
 * A driver class to illustrate the addem class
 * 
 * @author (David John) 
 * @version (November, 2009)
 */
public class driver
{

/**
 * The main thread of the program.
 */
  public static void main(String[] args)
  {
      
      // set the number of cells in the array (inside of addem), and the number
      // of threads to be used in the computation
      int numbercells=1000000;
      int numberthreads=20;
      
      // create an array of addem objects, one for each thread
      addem [] xthreads = new addem[numberthreads];
     
      // for each addem object in the array, call the constructor to
      // set the start/end indices for a computation
      for(int i=0;i<numberthreads;i++)
      {
          xthreads[i] = new addem(i*numbercells/numberthreads,(i+1)*numbercells/numberthreads);
        }
      
      // generate the shared array
      addem.generatearray(numbercells);
      
      // start a timer for the computation
      long start = System.currentTimeMillis();
      
     // start up all the concurrent processes
     for(int i=0;i<numberthreads;i++)
     {
         xthreads[i].start();
        }
      
      // now wait for each concurrent process to finish
      try
      {
         for(int i=0;i<numberthreads;i++)
         {
             xthreads[i].join();
            }
        }catch(InterruptedException e){};
        
        // from each of the addem objects get the partial result, add
        // all of these together
        double answer = 0.0;
        for(int i=0;i<numberthreads;i++)
        {
             answer += xthreads[i].getresult();
        }
        
        
       // the result is finally computed, get the time
       long finish = System.currentTimeMillis();
       
    
       // print the final answer, and the elapsed time required for the computation
        System.out.println("\n\nThe sum is " + answer);
        System.out.println("The elapsed time in milliseconds is:  "+ (finish-start));
        System.out.println("The array size is:  "+numbercells);
        System.out.println("The number of threads used:  "+numberthreads);
}

}