package microbenchmarkmpiJava.reduce;

//
// mpiJava version : Taboada
//                   July 2002
// DES
//
//package mpi;

import java.io.*;
import java.text.NumberFormat;
import java.lang.Math;
import mpi.*;

public class Reduce {

  public static void main(String[] args) throws MPIException {
  }

  public Reduce() {
  }

  public Reduce(String[] args) throws Exception {

    double      startwtime, endwtime, pot2npesd;
    int         i, iterations, size, ns, my_pe, npes, ndoubles, pot2npes, pot2size;
    Status      status;

    MPI.Init(args);

    my_pe = MPI.COMM_WORLD.Rank();
    npes  = MPI.COMM_WORLD.Size();

    MPI.COMM_WORLD.Barrier();

	iterations = Integer.parseInt(System.getProperty("ITERATIONS"));
	
	size = Integer.parseInt(System.getProperty("SIZE"));
	
	ndoubles = size/8;	

	  
    double A[] = new double [ndoubles];
    double B[] = new double [ndoubles];	
	 
	double timesBcast[] = new double [iterations];
	double timesBcastReduce[] = new double [iterations];
	        
	for (i = 0; i < ndoubles; i++) {
		A[i] = (double) 1. / (i + 1);
	}

		pot2npes = (int)(Math.log(npes)/0.69314718);
		pot2npesd = (double)(Math.log(npes)/0.69314718);
		
		pot2size = (int)(Math.log(size)/1.386294361);
		if (pot2size < 0) pot2size = 0;	  

	    for (ns = 0; ns < iterations; ns++) {
	   		  MPI.COMM_WORLD.Barrier();		  
			  startwtime = MPI.Wtime();					
	          MPI.COMM_WORLD.Reduce(A, 0, B, 0, ndoubles, MPI.DOUBLE, MPI.MAX, 0);
			  endwtime = MPI.Wtime();
			  
		  	  timesBcast[ns] = (double) (1000000*(endwtime - startwtime));	
		  			  
			}
   		
		MPI.COMM_WORLD.Reduce(timesBcast, 0, timesBcastReduce, 0, iterations, MPI.DOUBLE, MPI.MAX, 0);

		if (my_pe == 0) {
			//Format the Number to Display
			NumberFormat nf = NumberFormat.getInstance();
			nf.setMaximumFractionDigits(6);
        	nf.setMinimumFractionDigits(6);	
			  
			for (i = 0; i < iterations; i++) {
				System.out.print(nf.format((double) timesBcastReduce[i]/1000000)+" \t "+(long) timesBcastReduce[i]+" \t "+nf.format((double)(size/(timesBcastReduce[i])))); 
 				System.out.println(" \t "+npes+" \t "+pot2npes+" \t "+nf.format(pot2npesd)+" \t "+size+" \t "+pot2size);     		  
			}
		}
		
    MPI.Finalize();    
   if(my_pe == 0) 
     System.out.println("Reduce TEST COMPLETE");	   
  }
}