/*  heateqn.c

    Chris Nevison
    modified by Wal Maxey and Xiannong Meng as MPI lab
    in Parallel Computing Workshop, Colgate U.
    July 14, 1997
    June 27, 1997

    This program solves the heat equation for a rectangle with
    fixed boundary values.  The values are converted into color
    pixels, ranging from blue for coldest, through green for
    medium, to red for hottest.

*/

#include <stdio.h>
#include <stdlib.h>
#include "graphics.h"
#include "heat.h"
#include "mpi.h"

int main(int argc, char* argv[])
{
  char filename[30];
  FILE * infile;
  FILE * outfile;
  int numrows, numcols, maxiter;
  double * row0; double * rowmax;
  double * col0; double * colmax;
  double * * mat; double tol;
  double minval; double maxval;
  double startTime, endTime;
  Pixel * * pmap;

  MPI_Init(&argc, &argv);         /* start MPI   */

  printf("Enter input file name: ");
  scanf("%s", filename);
  if((infile = fopen(filename, "r+b")) == NULL){
    printf("unable to open input file %s, exiting program.\n\n",
           filename);
    exit(1);
  }

  printf("Enter output file name: ");
  scanf("%s", filename);
  if((outfile = fopen(filename, "w+b")) == NULL){
    printf("unable to open output file %s, exiting program.\n\n",
           filename);
    exit(2);
  }

  printf("Enter tolerance for heat computation: ");
  scanf("%lf", &tol);
  printf("\nEnter maximum number of iterations: ");
  scanf("%d", &maxiter);

  startTime = MPI_Wtime();
  ReadHeatBndry(infile, &numrows, &numcols,
                &row0, &rowmax, &col0, &colmax);

  SolveHeat(row0, rowmax, col0, colmax, 
            numrows, numcols, tol, maxiter, &mat);

  FindMinMax(numrows, numcols, mat, &minval, &maxval);

  CreatePixelMap(numrows, numcols, &pmap);

  DMatToPMap(mat, minval, maxval,
             numrows, numcols, pmap);

  StoreTGAHeader(outfile, numrows, numcols);

  StorePixelBlock(outfile, numrows, numcols, pmap);

  endTime = MPI_Wtime();
  printf(" TOTAL TIME : %10.4f seconds\n",endTime - startTime);
  MPI_Finalize();               /* shut down MPI */
  return 0;
}