Trouble getting stuck in while loop for finite difference method problem

I am trying to print the values at nodes (2,2) (2,6) (6,2) and (6,6) but I believe the code is never coming out of the while loop. I am using the finite difference method. When I pause the code while it's running and open my "mesh," it is showing the correct values. Does anyone know how I can get it to print these values? Thank you.

%establishes 7x7 matrix

m = 7;

n = 7;

mesh(2:6,2:6) = input('Guess the overall internal temperature: ');

%establish boundry conditions on the matrix (the mesh)

mesh(1,:) = 0; %temp at top of matrix = 0

mesh(:,1) = 200; %temp at bottom = 200C

mesh(m,:) = 300; %left is 300

mesh(:,n) = 10; %right is 10

newMesh(m,n)=mesh(m,n);

while newMesh(2,2) - mesh(2,2) <= 1 && newMesh(6,6) - mesh(6,6) <= 1 %saying the difference between matricies must be less that .1C

for m = 2:6

for n = 2:6

newMesh(m,n) = (mesh(m+1,n)+ mesh(m-1,n) + mesh(m,n+1) + mesh(m,n-1)) / 4; %getting the temperatures of nodes above, below, and on either side of point

mesh(m,n) = newMesh(m,n); %display "mesh(m,n)" with updated values.

end

end

end

fprintf('The final temperature of the nodes are %4.2f, %4.2f, %4.2f, %4.2f', mesh(2,2), mesh(2,6), mesh(6,2), mesh(6,6));

Answer 1

[darova]

Define newMesh:

% newMesh(m,n)=mesh(m,n); % only (7,7) element will be nonzero
newMesh = mesh;           % use this instead

Here you are saying: if difference between (2,2) and (6,6) elemnts is LESS than 1 do loop

while newMesh(2,2) - mesh(2,2) <= 1 && newMesh(6,6) - mesh(6,6) <= 1 %saying the difference between matricies must be less that .1C

After for loop mesh will always be equal to newMesh (mesh==newMesh). So while loop never repeats or repeats infinitely

mesh(m,n) = newMesh(m,n); %display "mesh(m,n)" with updated values.