%Blahblah Uncle Don's T-Line using Cylindrical Coordinates
%First build A Matrix for 3 circles divided into 8 pies

romax=3; %romax is the total ro values we take
simax=8; %simax is the divisions of the coordinate system

siz = romax*simax; %size of the A matrix

A = eye(siz)*0; %this sucka is just the matrix with no values in yet. It's reset to zero
B = zeros(siz,1);
k = 1:siz;
k(9)=0,k(11)=0;k(13)=0;k(17:24)=0;
n = 1:siz;

%And now let's build the functions to calculate the constants for our 
%cylindrical coordinate finite difference method calculations
delro = 0.005; %5 cm
delsi = pi/4; %psi increment in radians
ronot = 0.01; %the circle layer distance from origin

%inner node ~closer to origin
Ao = 1-delro/2/ronot;

%outer node ~towards edge
Bo = 1+delro/2/ronot;

%counterclockwise node and clockwise node
Co = (delro/ronot/delsi)^2;

%original node ~the center node
Do = -(2+2*(delro/ronot/delsi)^2);

for n = 1:siz,k=1:siz
    if k~=simax*k, k~=simax*k-7
        if k(n-simax) ~= 0
            A(k,k-simax) = Ao;
        end
        
    end
end
V=A\B;
V=V(1:siz,1);

Phi = reshape(V,romax,simax);
tline(1:5,1:8)=0;
hole(1,1:8)=65;
edge(5,1:8)=0;

tline(2:4,1:8)=Phi;
tline(1,1:8)=hole;

tline


k