function R=MakeRegmatrixFace(Element);% Function R=MakeRegmatrixFace(Element);% computes a regularization matrix R which is a% version of 2D difference. %% INPUT%% Element = element structure%% OUTPUT%% R = regularisation matrix% M. Vauhkonen 13.8.1999, Univeristy of Kuopio, FinlandFacelist=[];for ii=1:max(size(Element)) Fl=[Element(ii).Face{:,2}]'; fFl=find(Fl); add=[ones(max(size(fFl)),1)*ii,Fl(fFl)]; Facelist=[Facelist;add];endFacelist=sort(Facelist')';Facelist=unique(Facelist,'rows');[rN,cN]=size(Facelist);R=sparse(rN,max(max(Facelist)));for ii=1:rN R(ii,Facelist(ii,:))=[1,-1];end