/* 
 
 Written by:
 -- 
 John L. Weatherwax                2006-05-30
 
 email: wax@alum.mit.edu
 
 Please send comments and especially bug reports to the
 above email address.
 
-----
*/ 

#include "ind2sub.h"


/* A block row version -- compatable with C's conventions if 
   M=4 & N=3 then given an index (the first number in the below)
   this routine returns the paired number below

   0=(0,0)    1=(0,1)     2=(0,2)
   3=(1,0)    4=(1,1)     5=(1,2)
   6=(2,0)    7=(2,1)     8=(2,2)
   9=(3,0)    10=(3,1)    11=(3,2)

*/ 
void ind2sub(int M, int N, int ind, int *i, int *j){

  *j = ind % N;   
  *i = (ind-(*j)) / N; 

}

void test_ind2sub(void){

  int M,N,ind,i,j;

  M=4; N=3; 
  for( ind=0; ind < 12; ind++ ){
    ind2sub(M,N,ind,&i,&j);
    printf("ind=%d; (i,j)=(%d,%d)\n",ind,i,j); 
  }

}