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