function invariant=intersect_complements(locations,loc)%This function takes all of the complements of all if the guards for the location 'loc'%and intersects them.  The resulting regions are the 'invariant'.global CELLSprevious_invariant=locations{loc}.transitions{1}.guard_compl;if length(locations{loc}.transitions)>1    %Intersect the first set of complements with the 2nd.  Then intersect that result    %with the 3rd, and so on    for j=2:length(locations{loc}.transitions)        % moved        new_guard_compl=locations{loc}.transitions{j}.guard_compl;        invariant=[];        for k=1:length(new_guard_compl)            new_cell=new_guard_compl(k);            new_hps=CELLS{new_cell}.boundary;            new_hpflags=CELLS{new_cell}.hpflags;            new_pthflags=CELLS{new_cell}.pthflags;            for i=1:length(previous_invariant)                existing_guard_compl=previous_invariant(i);                old_hps=CELLS{existing_guard_compl}.boundary;                old_hpflags=CELLS{existing_guard_compl}.hpflags;                old_pthflags=CELLS{existing_guard_compl}.pthflags;                [intersection_boundary,intersection_hpflags]=clean_up_boundary(old_hps,new_hps,old_hpflags,new_hpflags);                if ~isempty(intersection_boundary)                    repeat_test=is_repeat(intersection_boundary,intersection_hpflags);                    if repeat_test~=0                        %************************************************                        %Since this CELL already exists, just point to the existing CELL                        invariant=[invariant repeat_test];                        %Now update existing pthb flag list                        for p=1:length(old_pthflags)                            if old_pthflags(p)~=-1                                pthflags(p)=old_pthflags(p);                            elseif new_pthflags(p)~=-1                                pthflags(p)=new_pthflags(p);                            elseif CELLS{repeat_test}.pthflags(p)~=-1                                pthflags(p)=CELLS{repeat_test}.pthflags(p);                            else                                pthflags(p)=-1;                            end                        end                        %***********************************************                    else                        new_cell=length(CELLS)+1;                        %************************************                        CELLS{new_cell}.boundary = intersection_boundary;                        CELLS{new_cell}.hpflags = intersection_hpflags;                        for p=1:length(old_pthflags)                            if old_pthflags(p)~=-1                                pthflags(p)=old_pthflags(p);                            elseif new_pthflags(p)~=-1                                pthflags(p)=new_pthflags(p);                            else                                pthflags(p)=-1;                            end                        end                        CELLS{new_cell}.pthflags = pthflags;                        %*************                        invariant=[invariant new_cell];                    end                end            end        end        previous_invariant=invariant;    endelse    invariant=previous_invariant;endif isempty(invariant)    name=locations{loc}.state;    fprintf(1,'\nWARNING: Location "')    for i=1:size(name,1)        fprintf(1,'%s ',name(i,:))    end    fprintf(1,'" has no guard invariant.\n')endreturn% ----------------------------------------------------------------------------