/********************************************************
% 
% Written by:
% -- 
% John L. Weatherwax                2005-05-25
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----

 A simple serial matrix multiplication program
 (Matrix_A  X  Matrix_B) => Matrix_C

*/

#include <stdio.h>
#include <stdlib.h>

int **wMA,**wMB,**wMC;

/*
 * Main: allocates matrix, assigns values, computes the results
 */
extern int 
main(int argc, char* argv[])
{
  int size, row, column;
  int i,j; 
  
  /* Check input arguments */
  if( argc < 2 | argc > 2 ){
    fprintf(stderr,"Expecting one input argument: *n* (size of matrices)\n"); 
    exit(1);
  }

  /* Extract out the requested matrix size */
  size = atoi(argv[1]);
  if( size <= 0 ){
    fprintf(stderr,"Input argument *n* must be positive\n"); 
    exit(1); 
  }

  /* Create space for the matrices: */ 
  /* wMA: */
  wMA = (int**) malloc( size * sizeof(int*) );
  if( !wMA ){
    fprintf(stderr,"Memory couldn't be created\n"); 
    exit(1);
  }
  for( row=0; row < size; row++ ){
    wMA[row] = malloc( size*sizeof(int) );
    if( !wMA[row] ){
      fprintf(stderr,"Memory couldn't be created\n"); 
      exit(1);
    }
  }
  /* wMB: */
  wMB = (int**) malloc( size * sizeof(int*) );
  if( !wMB ){
    fprintf(stderr,"Memory couldn't be created\n"); 
    exit(1);
  }
  for( row=0; row < size; row++ ){
    wMB[row] = malloc( size*sizeof(int) );
    if( !wMB[row] ){
      fprintf(stderr,"Memory couldn't be created\n"); 
      exit(1);
    }
  }
  /* wMC: */
  wMC = (int**) malloc( size * sizeof(int*) );
  if( !wMC ){
    fprintf(stderr,"Memory couldn't be created\n"); 
    exit(1);
  }
  for( row=0; row < size; row++ ){
    wMC[row] = malloc( size*sizeof(int) );
    if( !wMC[row] ){
      fprintf(stderr,"Memory couldn't be created\n"); 
      exit(1);
    }
  }
  
  /* Fill in matrix values, currently values are hardwired */
  for (row = 0; row < size; row++) {
    for (column = 0; column < size; column++) {
      wMA[row][column] = 1;
    }
  }
  for (row = 0; row < size; row++) {
    for (column = 0; column < size; column++) {
      wMB[row][column] = 1;
    }
  }
  for (row = 0; row < size; row++) {
    for (column = 0; column < size; column++) {
      wMC[row][column] = 0;
    }
  }

  /* Print matrices before: */ 
  printf("MATRIX: The A array is;\n");
  for(row = 0; row < size; row ++) {
    for (column = 0; column < size; column++) {
      printf("%5d ",wMA[row][column]);
    }
    printf("\n");
  }
  printf("MATRIX: The B array is is;\n");
  for(row = 0; row < size; row ++) {
    for (column = 0; column < size; column++) {
      printf("%5d ",wMB[row][column]);
    }
    printf("\n");
  }

  /* Process Matrix, by row, column. */
  for(row = 0; row < size; row++) {
    for (column = 0; column < size; column++) {
      for( i=0; i < size; i++ ) {
	wMC[row][column] += wMA[row][i]*wMB[i][column];
	  }
    }
  }

  /* Print results */
  printf("MATRIX: The resulting matrix C is;\n");
  for(row = 0; row < size; row ++) {
    for (column = 0; column < size; column++) {
      printf("%5d ",wMC[row][column]);
    }
    printf("\n");
  }
  return 0;
}