ns_faceEdgeId.m

function fed=ns_faceEdgeId(edge,face,gmp,rg,fId)

fvr=face{2}{fId};
eVr=edge{1}(:,rg.ei(1):rg.ef(1));

if size(fvr,2)>2
    fvrc=[fvr,fvr(1)];    
    fed=zeros(1,size(fvr,2));

    for jj=1:size(fvrc,2)-1
        if fvrc(jj)<fvrc(jj+1)
            eid=find(ismember(eVr,fvrc(jj:jj+1),'rows')==1);
            if size(eid,1)==1
                fed(jj)=eid;
            else
                efid=edge{1}(eid(1),rg.ei(2):rg.ef(2));
                efid=efid(efid==fId);
                if isempty(efid)==1
                    fed(jj)=eid(2);
                else
                    fed(jj)=eid(1);
                end               
            end
        else
            eid=find(ismember(eVr,[fvrc(jj+1),fvrc(jj)],'rows')==1);
            if size(eid,1)==1
                fed(jj)=-eid;
            else
                efid=edge{1}(eid(1),rg.ei(2):rg.ef(2));
                efid=efid(efid==fId);
                if isempty(efid)==1
                    fed(jj)=-eid(2);
                else
                    fed(jj)=-eid(1);
                end 
            end
        end
    end
    
% cells with one neighbors only
elseif size(fvr,2)==2
    if fvr(1)<fvr(2)
        eId=find(ismember(eVr,fvr,'rows')==1 & ...
            (edge{1}(:,3)==fId | edge{1}(:,4)==fId));
        fedInd=[eId(1),-eId(2)];
    else
        eId=find(ismember(eVr,[fvr(2),fvr(1)],'rows')==1 & ...
            (edge{1}(:,3)==fId | edge{1}(:,4)==fId));
        fedInd=[-eId(1),eId(2)];
    end
    farInd=ns_faceArea(fedInd,edge{2},gmp.bs,gmp.sstn);
    if farInd>0
        fed=fedInd;
    else
        fed=[-fedInd(2),-fedInd(1)];
    end   

else
    eId=find(ismember(eVr,[fvr(1),fvr(1)],'rows')==1);
    fedInd=eId;
    farInd=ns_faceArea(fedInd,edge{2},gmp.bs,gmp.sstn);
    if farInd>0
        fed=fedInd;
    else
        fed=-fedInd;
    end
end

end