Hello.
I'm trying to solve a partial differential equation of the type that can be solved with pdepe. I based my code on the one I found in the Help. The only trick of my code is that one of the boundary conditions contains a time-dependent parameter that has to be numerically determined ("qs" below). My code is the following:
Variables that have to be defined in the Command Window:
sigma = 0;
DC = 5.82E-12;
R = 1E-5;
t = 0:1000;
A = [0.610, -0.238, 0.093];
c_in = 2/3 .* cos(0.01 .* t);
c = c_in;
Then, the main file looks like this:
function q = q_mpd_km(sigma, R, t)
r = linspace(0, R, 20);
sol = pdepe(sigma, @q_pde_de, @q_pde_ic, @q_pde_bc, r, t);
q = sol(:,:,1);
with the following file containing the differential equation:
function [c, f, s] = q_pde_de(r, t, q, DqDr)
global DC
c = 1;
f = DC .* DqDr;
s = 0;
the one with the initial condition:
function q = q_pde_ic(r)
q = 0;
and the one containing the boundary conditions:
function [Pl, Ql, Pr, Qr] = q_pde_bc(rl, ql, rr, qr, t)
global DC A c
qs = zeros(1, length(t));
S = zeros(1, length(A));
for i = 1:length(t)
for j = 1:length(A)
S(j) = A(j) .* c(i).^j ;
end
qs(i) = sum(S);
end
Pl = 0;
Ql = 1 ./ DC;
Pr = qr - qs;
Qr = 0;
As I enter
q = q_mpd_km(sigma, R, t);
in the Command Window, I get the following error message:
??? Attempted to access qL(1); index out of bounds because numel(qL)=0.
Error in ==> pdepe at 269
if qL(j) == 0
Error in ==> q_mpd_km at 13
sol = pdepe(sigma, @q_pde_de, @q_pde_ic, @q_pde_bc, r, t);
I looked at the pdepe file (line 269) but it does not help much! Can you help me? Does this qL have anything to do with my parameter Ql? If not, what is it? Thank for your help.
Tibo
