I copied and pasted the code from the worksheet on my laptop to reproduce it, and it didn't work. I copied and pasted it from this page to a uni computer, and it seems to produce the following result:

module() export plot, plot3d, animate, value, settings; ... end module

Then typing in plot(pds); gives a graph that looks very much like x=y, which isn't what I was expecting, and typing plot(pds,t) or plot(pds,R) doesn't work very well. I'll talk to my professor later today about that – thanks for your help!

I copied and pasted the code from the worksheet on my laptop to reproduce it, and it didn't work. I copied and pasted it from this page to a uni computer, and it seems to produce the following result:

module() export plot, plot3d, animate, value, settings; ... end module

Then typing in plot(pds); gives a graph that looks very much like x=y, which isn't what I was expecting, and typing plot(pds,t) or plot(pds,R) doesn't work very well. I'll talk to my professor later today about that – thanks for your help!

> PDE := diff(Sigma(R, t), t) = 3*(diff(R^.5*(diff(Sigma(R, t)*R^.5, R)), R))/R;
> IBC := {Sigma(0, t) = 0, Sigma(9999, t) = 0, Sigma(R, 0) = 0};
> pds := pdsolve(PDE, IBC, numeric, Sigma(R, t), time = t, range = 0 .. 9999);
%;
Error, (in pdsolve/numeric/process_PDEs) number of dependent variables and number of PDE must be the same
>
 

We have a different error, but now it's complaining that the number of variables is wrong, when as far as I can tell it shouldn't be (the same thing happened when we included indepvars, I took that out thinking it'd solve the problem and it didn't) – any further pointers you could give would be really helpful! Thank you.

> PDE := diff(Sigma(R, t), t) = 3*(diff(R^.5*(diff(Sigma(R, t)*R^.5, R)), R))/R;
> IBC := {Sigma(0, t) = 0, Sigma(9999, t) = 0, Sigma(R, 0) = 0};
> pds := pdsolve(PDE, IBC, numeric, Sigma(R, t), time = t, range = 0 .. 9999);
%;
Error, (in pdsolve/numeric/process_PDEs) number of dependent variables and number of PDE must be the same
>
 

We have a different error, but now it's complaining that the number of variables is wrong, when as far as I can tell it shouldn't be (the same thing happened when we included indepvars, I took that out thinking it'd solve the problem and it didn't) – any further pointers you could give would be really helpful! Thank you.