wolffd@0: function pot = recursive_combine_pots(pot1, pot2)
wolffd@0: % RECURSIVE_COMBINE_POTS recursive combine two potentials
wolffd@0: % pot = recursive_combine_pots(pot1, pot2)
wolffd@0: 
wolffd@0: pot1 = reduce_pot(pot1);
wolffd@0: pot2 = reduce_pot(pot2);
wolffd@0: % Recursion is stopped, if recusive-combination is defined by direct combination, 
wolffd@0: % i.e. if the domain of one potential is disjoint from the head of the other.
wolffd@0: if (isempty(myintersect(pot1.domain,pot2.cheaddom))|...
wolffd@0:     isempty(myintersect(pot1.cheaddom,pot2.domain)))    
wolffd@0:     pot = direct_combine_pots(pot1,pot2);
wolffd@0: else 
wolffd@0:     % Test wether one of the set-differences is not empty 
wolffd@0:     % as defined in Lauritzen99 "Stable Local Computation with Conditional Gaussian Distributions"
wolffd@0:     % on page 9
wolffd@0:     D12 = mysetdiff(pot1.cheaddom, pot2.domain);
wolffd@0:     D21 = mysetdiff(pot2.cheaddom, pot1.domain);
wolffd@0:     if (isempty(D12) & isempty(D21))
wolffd@0:        assert(0,'Recursive combination is not defined');
wolffd@0:     end
wolffd@0: 
wolffd@0:     if ~isempty(D12)
wolffd@0:         % Calculate the complementary potential for the set 
wolffd@0:         % D1\D12 as defined in Lauritzen 99, page 9
wolffd@0:     keep = mysetdiff(pot1.domain,D12);
wolffd@0:         [margpot, comppot] = complement_pot(pot1,keep);
wolffd@0:         margpot = reduce_pot(margpot);
wolffd@0:         comppot = reduce_pot(comppot);
wolffd@0:         pot = direct_combine_pots( recursive_combine_pots(margpot, pot2), comppot);
wolffd@0:     elseif ~isempty(D21)
wolffd@0:         keep = mysetdiff(pot2.domain,D21);
wolffd@0:         [margpot, comppot] = complement_pot(pot2,D21);
wolffd@0:         margpot = reduce_pot(margpot);
wolffd@0:         comppot = reduce_pot(comppot);
wolffd@0:         pot = direct_combine_pots( recursive_combine_pots(pot1, margpot), comppot);
wolffd@0:     end
wolffd@0: end
wolffd@0: 
wolffd@0: 
wolffd@0: