wolffd@0: function [reduced_pot,successful] = reduce_pot(pot,tailnodes)
wolffd@0: % Executes the reduce operation defined in
wolffd@0: % Stable Local Computation with Conditional Gaussian Distributions
wolffd@0: % Steffen L. Lauritzen
wolffd@0: % Frank Jensen
wolffd@0: % September 1999
wolffd@0: % The potential pot is reduced if B contains any zero columns
wolffd@0: % The test are restricted to the positions in tailnodes.
wolffd@0: % Any columns successfully deleted are entered in the array successful
wolffd@0: if nargin < 2
wolffd@0:     tailnodes = pot.ctaildom;
wolffd@0: end
wolffd@0: 
wolffd@0: successful = [];
wolffd@0: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
wolffd@0: % Keep track of remaining tailnodes %
wolffd@0: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
wolffd@0: rem_tailnodes = pot.ctaildom;
wolffd@0: for i = tailnodes
wolffd@0:     pos = find(i==rem_tailnodes);
wolffd@0:     successful_red = [pos];
wolffd@0:     red_scgcpot = cell(1,pot.dsize);
wolffd@0:     j = 1;
wolffd@0:     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
wolffd@0:     % Test whether all components of pot.scgpotc can be reduced %
wolffd@0:     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
wolffd@0:     while ((j <= pot.dsize) & ~isempty(successful_red))
wolffd@0:         [cpot,successful_red] = reduce_pot(pot.scgpotc{j},pos);
wolffd@0:         red_scgcpot{j} = cpot;
wolffd@0:         j = j + 1;
wolffd@0:     end
wolffd@0: 
wolffd@0:     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
wolffd@0:     % If i is a reducible tailnode, then reduce the potential %
wolffd@0:     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
wolffd@0:     if ~isempty(successful_red)
wolffd@0:         successful = [successful i];
wolffd@0:         pot.scgpotc = red_scgcpot;
wolffd@0:         rem_tailnodes = mysetdiff(rem_tailnodes,i);
wolffd@0:     end;
wolffd@0: end
wolffd@0: 
wolffd@0: pot.ctaildom = rem_tailnodes;
wolffd@0: positions = find_equiv_posns(rem_tailnodes,pot.ctaildom);
wolffd@0: pot.ctailsizes = pot.ctailsizes(positions);
wolffd@0: pot.ctailsize = sum(pot.ctailsizes);
wolffd@0: pot.domain = mysetdiff(pot.domain,successful);
wolffd@0: reduced_pot = pot;
wolffd@0: 
wolffd@0: 
wolffd@0: 
wolffd@0: 
wolffd@0: