/* Solution of hw1 with MPI */

#include "mpi.h"
#include "math.h"
#include <stdio.h>


/* All this is part of the student's work */

void power_distribute(double *A, double *b, long n);
void power_method(long k);
double power_answer(void);


int main(int argc, char *argv[])
{
  int i=0, n=4;
  int rank, size, allocated;

  double *A, *b, norm_b;
  long my_chunk;

  MPI_Init(&argc, &argv);

  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
  MPI_Comm_size(MPI_COMM_WORLD, &size);
  
  /* Create the matrix on the first node */
  if (0 == rank){
    allocated = size*(ceil((1.0*n)/size));
    A = (double *) malloc (allocated * n * sizeof(double));
    b = (double *) malloc (allocated * sizeof(double));

    if (NULL == A || NULL == b){
      printf ("Rank 0 has a problem with allocating memory\n");
      MPI_Finalize();
      return 0;
    }

    for (i=0; i<allocated*n; i++){
      A[i] = i;
    }

    for (i=0; i<allocated; i++){
      b[i] = i+1;
    }
  }

  /* Initialize the matrix using my matrix */
  power_distribute(A, b, n);
  
  /* Invoke the power method on it.  100 times */
  power_method(100);

  norm_b = power_answer();

  printf ("norm(b) = %e\n", norm_b);

  MPI_Finalize();
  return 0;
}