plotting with for loop

hello I am trying to solve FTCS discretization of the heat equation

and I have writtenn the below code:

I have 3 grid refinement, dx=[0.5,0.25,0.05];

I am going to plot 3 plot get for each grid (x,T1) in one plot. Currently, I can not plot 3 plot in one plot. I do not know how pull out T1 values after completion in for loop. Can someone tell me how to plot?

%setting up the parameters
clear;clc;;close all;
U0=2;
dt=0.01;
tf=1000;
ntotal=tf/dt;
dx=[0.5,0.25,0.05]; 
Kappa=0.001;
% boundary condition
for i=1:length(dx)
    x = (-3:dx(i):3);
    n=length (x);
    alpha=Kappa*dt./dx(i).^2;
    for j=1:n
  if (1<x(j)) || (x(j)<-1)
    T0(j)=0;
  else T0(j)=U0;
  end
end
%solving the problem with FTC

for k=1:ntotal 
   
for i=2:n-1
  T1(i) = T0(i) + alpha*(T0(i+1)-2*T0(i)+T0(i-1));
   T1(1)=T0(1) + alpha*(T0(2)-2*T0(1)+0);
   T1(n) = T0(n) + alpha*(0-2*T0(n)+T0(n-1));
end
T0=T1;

end

figure
plot (x,T1)
hold on
end

[Nima Vali]

Thank you very much.very helpful.

[Star Strider]

As always, my pleasure!

[Nima Vali]

Thank you.

Answer 1

[Star Strider]

To plot all of them on the same axes, put the figure call before the loop instead of inside it:

figure
hold on
for i=1:length(dx)
    x = (-3:dx(i):3);
    n=length (x);
    alpha=Kappa*dt./dx(i).^2;
    for j=1:n
        if (1<x(j)) || (x(j)<-1)
            T0(j)=0;
        else T0(j)=U0;
        end
    end
    %solving the problem with FTC
    for k=1:ntotal
        
        for i=2:n-1
            T1(i) = T0(i) + alpha*(T0(i+1)-2*T0(i)+T0(i-1));
            T1(1) = T0(1) + alpha*(T0(2)-2*T0(1)+0);
            T1(n) = T0(n) + alpha*(0-2*T0(n)+T0(n-1));
        end
        T0=T1;
    end
    plot (x,T1)
end
hold off
legend(compose('dx = %.2f',dx), 'Location','S')

.