How to stop my iteration Tn(j,i)=Tn+1(j,i)

clear clc
dx=0.5
nx=uint32(5/dx+1)
ny=uint32(5/dx+1)
[X Y]=meshgrid(linspace(0,5,nx),linspace(0,5,ny))
Tint=0
T=Tint*ones(ny,nx)

Tleft=100
Tright=0
Ttop=0
Tbottom=0
 
T(:,1)=Tleft
T(:,end)=Tright
T(1,:)=Ttop
T(end,:)= Tbottom

k=3
itr=200
 for k=1:itr
     for i=2:nx-1
        for j=2:ny-1
            T(j,i)=((T(j-1,i)+T(j+1,i)+T(j,i-1)+T(j,i+1))/4)            
        end   
    end
 end
 
[Xq Yq]= meshgrid(linspace(0,5,nx*10),linspace(0,5,ny*10));
colormap jet
Vq=interp2(X,Y,T,Xq,Yq,'cubic',0);

This is my code. My iteration 200 but i want my code stop when Tn(j,i)=Tn+1(j,i) . But i dont know how to break for end...

Answer 1

[Alan Stevens]

Replace your for loop by:

tol = 10^-6; % Or whatever is appropriate
err = 1;
 while err>tol
     Told = T;
     for i=2:nx-1
        for j=2:ny-1
            T(j,i)=((T(j-1,i)+T(j+1,i)+T(j,i-1)+T(j,i+1))/4);            
        end   
     end
    err = max(max(abs(T - Told)));
 end