MATLAB: Not enough input arguments

errorMATLAB

I am using the 'pdepe' command but I keep getting this error-
Not enough input arguments.
Error in differential>pde1pde (line 15)
k = (1.22-0.002*u)/36;
Error in differential (line 12)
sol = pdepe(m, pde1pde, pde1ic, pde1bc, x, t);
Here's the code I have-
clc
global rho Cp MW dH T0
rho = 906;
Cp = 0.4365;
MW = 104.15;
dH = -17800;
T0 = 20 + 273.15;
x = linspace(0,10,20);
t = linspace(0, 1000000, 10000);
m = 0;
sol = pdepe(m, pde1pde, pde1ic, pde1bc, x, t);
function [c,f,s] = pde1pde(x, t, u, dudx)
    k = (1.22-0.002*u)/36;
    xp = 1-x;
    
    A0 = 1.964*(10^5)*exp(-10040/u);
    A1 = 2.57-5.05*u*(10^(-3));
    A2 = 9.56-1.76*u*(10^(-2));
    A3 = -3.03+7.85*u*(10^(-3));
    A = A0*exp(A1*(xp) + A2*(xp^2) + A3*(xp^3));
    
    c = (rho*Cp)/k;
    f = dudx;
    s = (((rho/MW)*x)^(2.5))*A*(-dH)/k;
end
function u0 = pde1ic(x)
    u0 = T0;
end
function [pl, ql, pr, qr] = pde1bc(xl, ul, xr, ur, t)
    pl = 0;
    ql = 1;
    pr = 0;
    qr = 1;
end

Best Answer

Exactly as the pdepe documentation explains (and its examples show) you need to provide three function handles as its 2nd, 3rd, and 4th inputs. Instead your code calls those three functions without any input arguments, thus the error message.
You can define three function handle like this:
sol = pdepe(m, @pde1pde, @pde1ic, @pde1bc, x, t);
%              ^         ^        ^ define function handles
Read more: https://www.mathworks.com/help/matlab/matlab_prog/creating-a-function-handle.html
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