plotting with for loop
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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
采纳的回答
Star Strider
2020-9-28
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')
.
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