# changing timestamp t and plotting the results.

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Ellie Matlab on 28 Jun 2022
Answered: Dyuman Joshi on 29 Jun 2022
I managed to code when t=0, but i still need to code for when t=1000 and when t=2000, as wellas plotting each of the graphs.
In which part of the code do i add so that i change t?   n=5;
dt=1000;
k=15;
rho=8055;
Cp=480;
deltax=1.6;
x=linspace(-0.8,0.8,n);
T=zeros(1,5); T(1,1)=40; T(1,5)=40;
figure
plot(x,T)
title('Temperature distribution at t=0')
xlabel('x')
ylabel('Temperature')
hold on;
##### 2 CommentsShowHide 1 older comment
Ellie Matlab on 28 Jun 2022
Edited: Ellie Matlab on 28 Jun 2022
I entered this code for the first 3 timestamps, how can i include a for loop that loops from t=0 to t=350000 to plot the temperature distribution at every timestep and use the pause command to observe the changes? The Temperaure is at 0degrees celsius everywhere else. n=5;
dt=1000;
k=15;
rho=8055;
Cp=480;
deltax=1.6;
x=linspace(-0.8,0.8,n);
deltax = x(2)-x(1);
T=zeros(1,5); T(1,1)=40; T(1,5)=40;
figure
plot(x,T)
title('Temperature distribution for first 3 timestamps')
xlabel('x')
ylabel('Temperature')
hold on;
T_old = T;
T(2:end-1) = T_old(2:end-1) + k/(rho*Cp) * dt * (T_old(3:end)-2*T_old(2:end-1)+T_old(1:end-2))/(deltax.^2);
plot(x,T)
hold on
T_old = T;
T(2:end-1) = T_old(2:end-1) + k/(rho*Cp) * dt * (T_old(3:end)-2*T_old(2:end-1)+T_old(1:end-2))/(deltax.^2);
plot(x,T)
%%for multiple timestamps
n=5;
dt=1000;
k=15;
rho=8055;
Cp=480;
deltax=1.6;
x=linspace(-0.8,0.8,n);
deltax = x(2)-x(1);
T=zeros(1,5); T(1,1)=40; T(1,5)=40;
t = 0;
dt = 1000;
for c = 1:t
for r = 1:t
T(r,c) = 1/(r+c-1);
pause(1000);
end
end
figure
plot(x,T)
title('Temperature distribution for first multiple timestamps')
xlabel('x')
ylabel('Temperature')

Dyuman Joshi on 29 Jun 2022
I am not sure if pause works here on the online/live editor, but it works nicely offline.
%building on Torsten's code
n=5;
dt=1000;
k=15;
rho=8055;
Cp=480;
x=linspace(-0.8,0.8,n);
deltax = x(2)-x(1);
T=zeros(1,5); T(1,1)=40; T(1,5)=40;
figure
plot(x,T)
xlabel('x')
ylabel('Temperature')
hold on;
for i=0:dt:35000
T_old = T;
T(2:end-1) = T_old(2:end-1) + k*dt/(rho*Cp)*(T_old(3:end)-2*T_old(2:end-1)+T_old(1:end-2))/(deltax.^2);
plot(x,T)
pause(0.1) %pausing 0.1 seconds between each plot
end R2020b

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