function [ed]=extract(edof,a)% ed=extract(edof,a)%-------------------------------------------------------------% PURPOSE%  Extract element displacements from the global displacement%  vector according to the topology matrix edof.%% INPUT:   a:  the global displacement vector%%         edof:  topology matrix%% OUTPUT: ed:  element displacement matrix%-------------------------------------------------------------% LAST MODIFIED: M Ristinmaa 1993-08-24% Copyright (c) 1991-94 by Division of Structural Mechanics and%                          Department of Solid Mechanics.%                          Lund Institute of Technology%-------------------------------------------------------------    [nie,n]=size(edof);%    t=edof(:,2:n);%    for i = 1:nie        ed(i,1:(n-1))=a(t(i,:))';    end%%--------------------------end--------------------------------