function int=grinprodgausnodequad(g,I);%grinprodgausnodequad Computes the gradient part of the system matrix%in the quadratic basis case. The conductivity  is in the linear basis.% Function int=grinprodgausnodequad(g,I);% computes the gradient part of the system matrix% in the quadratic basis case. The conductivity  is in the linear basis.%% INPUT%% g = nodes of the element% I = index of  the chosen node %% OUTPUT%% int = three dimensional array or 3x3 matrix of the values of integral% P. Ronkanen and M. Vauhkonen 10.5. 1996. Modified by M. Vauhkonen for EIDORS% 11.5.2000.% University of Kuopio, Department of Applied Physics, PO Box 1627,% FIN-70211 Kuopio, Finland, email: Marko.Vauhkonen@uku.fiw=[1/6*ones(3,1)];ip=[1/2 0;1/2 1/2;0 1/2];int=0; for ii=1:3  S=[1-ip(ii,1)-ip(ii,2);ip(ii,1);ip(ii,2)];  L=[4*(ip(ii,1)+ip(ii,2))-3, -8*ip(ii,1)-4*ip(ii,2)+4, ...     4*ip(ii,1)-1, 4*ip(ii,2), 0, -4*ip(ii,2); ...     4*(ip(ii,1)+ip(ii,2))-3, -4*ip(ii,1), ...     0, 4*ip(ii,1), 4*ip(ii,2)-1, -8*ip(ii,2)-4*ip(ii,1)+4];  Jt=L*g;  iJt=inv(Jt);  dJt=abs(det(Jt));  G=iJt*L;  int=int+w(ii)*S(I)*G'*G*dJt; end