SE_diff.asv

function [pw_se,w]=SE_diff(T,P,n)
E = 1e12; %Pa
v = .31;
t = .3; %nm
h = 10/(n+1); %nm
w = membrane_solution(T,P,n);
z = zeros(n+2);
z(2:end-1,2:end-1) = reshape(w,[n n]);
num = n + 1;
wbar = zeros(num);
for i = 1:num
    for j = 1:num
        wbar(i,j) = mean([z(i,j),z(i+1,j),z(i,j+1),z(i+1,j+1)]);
    end
end
pw = sum(wbar.*h^2.*P);
dwdx = zeros(num);
dwdy = zeros(num);
% for i = 1:num
%     for j = 1:num
%         dwdx(j,i) = z(i+1,j)-z(i,j);
%         dwdy(j,i) = z(i,j+1)-z(i,j);
%     end
% end
dwdx(:,1) = wbar(:,2)-wbar(:,1);
for i = 2:n
    dwdx(:,3) = wbar(:,n+1)-wbar(:,n-1);
end
% dwdx(:,4) = wbar(:,4)-wbar(:,3);
dwdy(1,:) = wbar(2,:)-wbar(1,:);
dwdy(2,:) = wbar(3,:)-wbar(1,:);
dwdy(3,:) = wbar(4,:)-wbar(2,:);

%se = E*t*h^2/(2*(1-v^2));