# too many input arguments when using pdepe

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ZIYI LIU el 25 de Mzo. de 2022
Comentada: ZIYI LIU el 25 de Mzo. de 2022
Hi, I meet a problem when using pdepe, and I tried many ways but can't solve this. Could you help me with this?
I got errors like 'too many/ not enough argument when using pdepe' when modifying
sol = pdepe(m,@(t,u) wave_ode1(x,t,u,dudx,p),@pdeic2,@pdebc2,x);
my code is below:
Thank you!
clear all
close all
hx = 0.1;%need try 0.01
L = 10;%
x = 0:hx:L;
t = [0:0.1:200];
Da=0.1;
Db=10;
m = 0;
p=[Da;Db];
sol = pdepe(m,@(t,u) wave_ode1(x,t,u,dudx,p),@pdeic2,@pdebc2,x);
u1 = sol(:,:,1);
u2 = sol(:,:,2);
surf(x,t,u1)
title('u_1(x,t)')
xlabel('Distance x')
ylabel('Time t')
surf(x,t,u2)
title('u_2(x,t)')
xlabel('Distance x')
ylabel('Time t')
function [c,f,s] = wave_ode1(x,t,u,dudx,p) % Equation to solve
c = [1; 1];
f = [Da; Db] .* dudx;
y = u(1) - u(2);
F = exp(5.73*y)-exp(-11.47*y);
s = [-F; F];
end
function u0 = pdeic2(x) % Initial Conditions
u0 = [1; 0];
end
function [pl,ql,pr,qr] = pdebc2(xl,ul,xr,ur,t) % Boundary Conditions
pl = [0; ul(2)];
ql = [1; 0];
pr = [ur(1)-1; 0];
qr = [0; 1];
end
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Torsten el 25 de Mzo. de 2022
sol = pdepe(m,@(x,t,u,dudx) wave_ode1(x,t,u,dudx,p),@pdeic2,@pdebc2,x,t);
function [c,f,s] = wave_ode1(x,t,u,dudx,p) % Equation to solve
c = [1; 1];
f = [p(1); p(2)] .* dudx;
y = u(1) - u(2);
F = exp(5.73*y)-exp(-11.47*y);
s = [-F; F];
end
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Torsten el 25 de Mzo. de 2022
elseif
else if
ZIYI LIU el 25 de Mzo. de 2022
Hi Torsten, I modified little based on your code and it works for me! Thank you so much!
function [c,f,s] = wave_ode1(x,t,u,dudx,p) % Equation to solve
Da=p(1);
Db=p(2);
c = [1; 1];
f = [Da; Db] .* dudx;
y = u(1) - u(2);
if t <= 20
ss = 0.05/2;
elseif t > 20 && t <= 25
ss = 0.05/4*(1+cos(pi*(t-20)/(25-20)));
else
ss = 0;
end
if x <= 1
ks = ss*(1+cos(pi*x));
else
ks = 1.0;
end
F = exp(5.73*y)-exp(-11.47*y)+ks;
s = [-F; F];
end

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### Más respuestas (1)

Walter Roberson el 25 de Mzo. de 2022
sol = pdepe(m,@(t,u) wave_ode1(x,t,u,dudx,p),@pdeic2,@pdebc2,x);
pdepe needs m, then three function handles, then x mesh, and then time span.
You have m, then three function handles, then x mesh... and no time span.
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ZIYI LIU el 25 de Mzo. de 2022
Hi Walter, I add t, but still have error said
'Error in wave (line 14)
sol = pdepe(m,@(t,u) wave11(x,u,dudx,p),@pdeic1,@pdebc1,x,t);'
Walter Roberson el 25 de Mzo. de 2022
The pdefun (first function handle) will be passed x, t, u, dudx. Your @(t,u) function handle expects to receive only two parameters.

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