/************************************************************
  File:          cholesky_master.cc                              
  Description:   A program that inputs a matrix from a file 
                 and computes the Cholesky decomposition 
		 using several processes.
                                                         
  Author:        Dana Vrajitoru                          
  Organization:  IUSB                                    
  Date:          August 16, 2002                           
**************************************************************/

#include <mpi.h>
#include <stdlib.h>
#include <iostream.h>
#include <fstream.h>
#include "cholesky_master.h"
#include "common.h"
	
// Asks for the file name, reads the matrix from the file, and sends
// each line to the corresponding slave process.
void Read_matrix(int proc_nr)
{ int i, j, size=proc_nr-1;
  char filename[20];
  float *a;
  a = new float[proc_nr-1];

  cout << "Enter the file name containing the matrix" << endl;
  cin >> filename;
  ifstream fin(filename);
  if (fin.good()) {
    for (i=1; i<proc_nr; i++) {
      for (j=0; j<size; j++)
	fin >> a[j];
      Send_float_array(i, a, size);
    }
    fin.close();
  }
  else
    cout << "Could not open the file" << endl;
}

// Asks for a file name for the result, collects the resulting matrix
// by line from the slave processes, then writes it to the file. Since
// the resulting matrix is 0 above the diagonal, the master only
// receives the part of the matrix on and below the diagonal.
void Write_solution(int proc_nr)
{ 
  int i, j;
  char filename[20];
  float *a;
  a = new float[proc_nr-1];
  
  cout << "Enter the file name for the result" << endl;
  cin >> filename;
  ofstream fout(filename);
  if (fout.good()) {
    for (i=1; i<proc_nr; i++) {
      Receive_float_array(i, a, i);
      for (j=0; j<proc_nr-1; j++)
	if (j<i)
	  fout << a[j] << '\t';
	else
	  fout << 0 << '\t';
      fout << endl; 
    }
  }
  else
    cout << "Could not open the output file" << endl;
  fout.close();
}

// The master function: inputs the data and writes the results.
void Master(int proc_nr)
{
  Read_matrix(proc_nr);
  Write_solution(proc_nr);
}