// MPI_JacobiEx.cpp
//
// Main program for testing parallel (MPI) Jacobi
//
// Adopted from the textbook
// Slightly different 
// To be modified by the user
//
// G.E.Karniadakis and R.M.Kirby II, 
// Parallel Scientific Computing in C++ and MPI, 
// Cambridge University Press, 2003
//
// ColoState, F06M676


#include <iostream.h>
#include <iomanip.h>
#include <mpi.h>
#include "SCmathlib.h"
#include "SCchapter7.h"

int main(int argc, char * argv[]) {
   int i,j, N = 20;
   double **A,*x,*q;
   int totalnodes, mynode;

   MPI_Init(&argc, &argv);
   MPI_Comm_size(MPI_COMM_WORLD, &totalnodes);
   MPI_Comm_rank(MPI_COMM_WORLD, &mynode);

   if (mynode==0) {
      A = CreateMatrix(N,N);
      x = new double[N];
      q = new double[N];

      for (i=0; i<N; i++) {
         q[i] = i+1;
         A[i][i] = -2.0;
         if (i<N-1) {
	    A[i][i+1] = 1.0;
	    A[i+1][i] = 1.0;
         }
      }
   }

   // Warning: the last argument is different from 
   // that in the subroutine
   Jacobi_P(mynode, totalnodes, N, A, x, q, 1.0e-14);
  
   if (mynode==0) {
      for (i=0; i<N; i++)  cout << x[i] << endl;
      DestroyMatrix(A,N,N);
      delete[] x;
      delete[] q;
   }

   MPI_Finalize();
   return 0;
}