%EidorsDemo2quad Demonstrates the use of 2D EIT Package with real measurements, potential in quadratic basis% EidorsDemo2quad Demonstrates the use of 2D EIT Package with real measurements  % using adjacent current injection patterns. The reconstructed image presents % static (absolute) resistivity values. % See also EidorsDemo2% M. Vauhkonen 28.3.2000,% University of Kuopio, Department of Applied Physics, PO Box 1627,% FIN-70211 Kuopio, Finland, email: Marko.Vauhkonen@uku.fiload meshdata2nd  % Data for two different meshes.NNode1=max(size(Node));                      %The number of nodesNElement1=max(size(Element));                %The number of elementNNode2=max(size(Node1));                      %The number of nodesNElement2=max(size(Element1));                %The number of elementsg1=reshape([Node.Coordinate],2,NNode1)';H1=reshape([Element.Topology],3,NElement1)';g2=reshape([Node1.Coordinate],2,NNode2)';H2=reshape([Element1.Topology],6,NElement2)';L=16;					  % The number of electrodes.z=0.005*ones(L,1);			  % Contact impedances.[II1,T]=Current(L,NNode2,'adj');	  % Adjacent current pattern.%Load some dataload bubble2.datmeas=bubble2(1280-255:1280);Uel=reshape(meas,16,16);Uel=RemoveVolt(Uel,L);%%             PROCEDURE TO SOLVE THE INVERSE PROBLEM           %%% Approximate the best homogenous resistivity.MeasPatt=-T;[Agrad,Kb,M,S,C]=FemMatrix(Node1,Element1,z);A=UpdateFemMatrix(Agrad,Kb,M,S,ones(NElement2,1));  % The system matrix.[Uref,p,r]=ForwardSolution(NNode2,NElement2,A,C,T,MeasPatt,'real');Urefel=Uref.Electrode;Urefel=RemoveVolt(Urefel,L);rho0=Urefel(:)\Uel(:);rho=rho0*ones(NElement2,1);A=UpdateFemMatrix(Agrad,Kb,M,S,1./rho);  % The system matrix.Uref=ForwardSolution(NNode2,NElement2,A,C,T,MeasPatt,'real',p,r);Urefel=Uref.Electrode(:);Urefel=RemoveVolt(Urefel,L);J=Jacobian(Node1,Element1,Agrad,Uref.Current,Uref.MeasField, ...           rho,'real');J=RemoveJacob(J,L);% Regularisation parameter and matrixalpha=0.001; R=MakeRegmatrix(Element1);iter=6;for ii=1:iter rho=rho+(J'*J+alpha*R'*R)\(J'*(Uel(:)-Urefel(:))-alpha*R'*R*rho); A=UpdateFemMatrix(Agrad,Kb,M,S,1./rho);  % The system matrix. Uref=ForwardSolution(NNode2,NElement2,A,C,T,MeasPatt,'real',p,r); Urefel=Uref.Electrode; Urefel=RemoveVolt(Urefel,L); J=Jacobian(Node1,Element1,Agrad,Uref.Current,Uref.MeasField,rho,'real'); J=RemoveJacob(J,L); clf,Plotinvsol(rho,g1,H1);drawnow;end