Adding Labels to PDE Graph

I was wondering how to add a label to a graph of multiple PDEs.

I want to label each line of the graph differently.

The functions I have are as follows:

function [pl,ql,pr,qr] = heatbc(xl,ul,xr,ur,t)
pl = ul;
ql = 0;
pr = ur;
qr = 0;
end

function u0 = heatic(x)
u0 = x.*(1-x);
end

function [c,f,s] = heatpde(x,t,u,dudx)
c = 1;
f = dudx;
s = 0;
end

With the main code being as such:

x = linspace(0,1,10);
t = [0 0.1 0.2 0.3];

m = 0;
sol = pdepe(m,@heatpde,@heatic,@heatbc,x,t)
u = sol(:,:,1);

plot(x,u); 
hold on; 

So far the graph looks as such:

I would just like to know how I would code a legend that labels the purple, orange, red and blue lines individually.

Thanks in advance!

Answer 1

[Alan Stevens]

One way is to do the following with your plot command:

plot(x,sol); 
lg1 = ['t = ',num2str(t(1))];
lg2 = ['t = ',num2str(t(2))];
lg3 = ['t = ',num2str(t(3))];
lg4 = ['t = ',num2str(t(4))];
legend(lg1,lg2,lg3,lg4)

[Madeleine Megg]

Thank You!