Pde toolbox: internal decsg error

Hello,

I'm using the decsg function to create a mesh with random circular inclusions. I have to do Monte Carlo simulations in order to estimate some mean values and standard deviations. It works fine but sometimes I get an "internal decsg error, (line 1435)". It occurs randomly and it is quite annoying since I have to generate at least 10000 realizations of the mesh.

Here is my code for generating the mesh with decsg:

     function [p, t, ConnectElemPhase, BoundaryNodes] = ...
           ConstructMesh(rayon, L, nbi, hmax)

%nbi: number of inclusions
%rayon: radius of the inclusions
%L: length of the representative volume element

a = -L+rayon+0.01; b = L-rayon-0.01; 
Cadre = [3, 4, -L, L, L, -L, -L, -L, L, L]';
centre = zeros(nbi, 2);
inclusions = zeros(10, nbi);

centre(1, :) = a + (b-a)*rand(2, 1); %center of the first inclusion
inclusions(:, 1) = [1, centre(1, :), rayon, 0, 0, 0, 0, 0, 0]';

SF = 'R';
C(1, 1) = {strcat(['C', num2str(1)])};
Ci = strcat(['+C', num2str(1)]);
SF = strcat([SF, num2str(Ci)]);

for i=2:nbi
centre(i, :) = a + (b-a)*rand(2, 1); %center of the i-th inclusion
dr = sqrt((centre(1:i-1, 1)-centre(i, 1)).^2 + ...
    (centre(1:i-1, 2)-centre(i, 2)).^2); 
%dr: distance between the i-th inclusion and the other inclusions 1, ..., i-1.

while any(dr<=2.1*rayon)
   % avoid intersection between the inclusions
   % if intersection, generate a new center
   centre(i, :) = a + (b-a)*rand(2, 1);
   dr = sqrt((centre(1:i-1, 1)-centre(i, 1)).^2 + ...
       (centre(1:i-1, 2)-centre(i, 2)).^2);
end

inclusions(:, i) = [1, centre(i, :), rayon, 0, 0, 0, 0, 0, 0]';

C(1, i) = {strcat(['C', num2str(i)])};
Ci = strcat(['+C', num2str(i)]);
SF = strcat([SF, num2str(Ci)]);

end

NS = [char('R', char(C))]'

GD = [Cadre, inclusions]; g = decsg(GD, SF, NS);

[p, e, t] = initmesh(g, 'Hmax', hmax, 'Hgrad', 1.2);

%...rest of the code not useful for my problem

Thank you for your help!

Brian.