I am trying to use MATLAB for generating random locations for non-uniform size spheres (non-overlapping) in a cube. The for loop in the code below never seems to end. I don't know what am missing in the code. I have ran the code for no. of spheres (n) = 10; dims = [ 10 10 10 ]

    function [ c r ] = randomSphere( dims )
    % creating one sphere at random inside [0..dims(1)]x[0..dims(2)]x...
    % radius and center coordinates are sampled from a uniform distribution 
    % over the relevant domain.
    % output: c - center of sphere (vector cx, cy,... )
    %         r - radius of sphere (scalar)
    r = rand(1); % you might want to scale this w.r.t dims or other consideration
    c = r + rand( size(dims) )./( dims - 2*r ); % make sure sphere does not exceed boundaries

   function ovlp = nonOverlapping( centers, rads )
   % check if several spheres with centers and rads overlap or not
   ovlp = false;
   if numel( rads ) == 1
   return; % nothing to check for a single sphere
   end
   dst = sqrt( sum( bsxfun( @minus, permute( centers, [1 3 2] ),...
                             permute( centers, [3 1 2] ) ).^2, 3) );
   ovlp = dst >= bsxfun( @plus, rads, rads.' ); %' all distances must be smaller than r1+r2
   ovlp = any( ovlp(:) ); % all must not overlap


   function [centers rads] = sampleSpheres( dims, n )
   % dims is assumed to be a row vector of size 1-by-ndim

   % preallocate
   ndim = numel(dims);
   centers = zeros( n, ndim );
   rads = zeros( n, 1 );
   ii = 1;
   while ii <= n
   [centers(ii,:), rads(ii) ] = randomSphere( dims );     
   if nonOverlapping( centers(1:ii,:), rads(1:ii) )
     ii = ii + 1; % accept and move on
   end
end