function DAT = cdf(loc,b,Dmax)

% CDF.M computes the CDF of Global k-Function for k_cdf.m  
%
% Written by: TONY E. SMITH, 5/11/99       
%
% INPUTS: 
% (i)   loc = file of locations (xi,yi), i=1..m 
% (ii)  b   = number of bins to use in CDF 
% (iii) Dmax = max pairwise distance to be considered 
% (this is usually half the max pairwise dist)  
      
% OUTPUTS: DAT = (1:b) vector containing CDF 
      
% List of Variables: 
% m,D,k,ub,C,n,bb,bin,Tot 
      
% Assertions for compiling 
      
%mbrealscalar(Dmax); 
            
% start 
      
m = length(loc(:,1)) ;

% Compute pairwise distances 
      
D = zeros(m*(m-1)/2, 1) ; %Matrix of loc-dist pairs 
           
i = 1 ;
           
k = 1 ;  %counter for D. 
        
while i < m 
               
	j = i + 1 ;       
         
   while j <= m 
                     
      D(k) = sqrt((loc(i,1) - loc(j,1))^2 + ...
                  (loc(i,2) - loc(j,2))^2 );
                        
      j = j + 1 ;          
            
      k = k + 1 ;           
          
    end        
         
    i = i + 1 ;    
         
end
      
      
% Count of point frequencies 
      
ub = ones(b,1); 
            
C = zeros(1,b) ; 
   
n = length(D) ; %number of distinct point pairs */
           
k = 1 ; 
            
while k <= n 
               
	if D(k) <= Dmax 
                     
		bb = ceil((D(k)/Dmax)*b); 
                        
      bin = max([1,bb]); %allows zero dists             
            
      C(bin) = C(bin) + 2 ; %adds (ij) and (ji)       
             
	end 
         
         
	k = k + 1 ; 
                  
end      
      
% Normalize point counts  
      
Tot = C*ub ; 
            
C = C/Tot ; 
            
% Construct CDF 
      
k = 1 ; 
            
while k < b 
   
   C(k + 1) = C(k + 1) + C(k) ; 
        
   k = k + 1 ;    
      
end      
      
DAT = C ;