grinprodgaus.m

来自「MATLAB二维电阻抗断层成像算法!用于医学成像,里面包括有限元剖分正问题,及反」· M 代码 · 共 29 行

function int=grinprodgaus(g,sigma);

%grinprodgaus Computes the integral of the product of the gradients in 2D FEM
% The function int=grinprodgaus(g,sigma);
% calculates the gradient part in the linear FEM in 2D EIT.
%
% INPUT
% g = nodal coordinates
% sigma = conductivity of the element
%
% OUTPUT
% int = value of the integral 

w=[1/6*ones(3,1)];
ip=[1/2 0;1/2 1/2;0 1/2];
L=[-1 1 0;-1 0 1];
Jt=L*g;
iJt=inv(Jt);
dJt=abs(det(Jt));
G=iJt*L;
%int=0;
% for ii=1:3
%  int=int+w(ii)*G'*G;
% end
%int=sigma*int*dJt;
int=1/2*sigma*G'*G*dJt;