Index exceeds the number of array elements (252).

4 vues (au cours des 30 derniers jours)
ummaab66
ummaab66 le 6 Nov 2020
Réponse apportée : Gautam le 1 Juil 2025
% Explicit Quickest scheme
clc; clear all;
xmin = 0; % [m]
xmax = 50*1000; % [m]
dx = 200; % [m]
tmax = 0.5*24*3600; % [s]
u = 0.45; % [m/s]
D=10; %[m2/s]
k=0.1/(24*3600); %[1/s]
dt = 50; % [s]
No = (xmax - xmin)/dx;
x = xmin : dx : xmax + dx;
%% initial and Boundary conditions
for i = 1:length(x)
if x(i)<=0
Co(i) = 100;
else
Co(i) = 0;
end
end
C = Co;
Cp = Co;
% Analytical solution
ns = tmax/dt;
for n = 1 : ns
for i = 1 : No+2
if x(i)<=u*tmax
d(i) = 100;
else
d(i) = 0;
end
end
end
% Quickest
ns = tmax/dt;
for n = 1 : ns
for i = 3 : No+2
F=D*dt/(dx)^2;
g=u*dt/dx;
gr= (C(i+1)-C(i))/dx;
gl=(C(i)-C(i-1))/dx;
cr=(C(i+1)-2*C(i)+C(i-1))/dx^2;
cl=(C(i-2)-2*C(i-1)+C(i))/dx^2;
Cp(i) = C(i)-g*((0.5*(C(i)+C(i+1))-0.5*dx*g*gr-0.166*dx^2*(1-g^2-3*F)*cr)-(0.5*(C(i-1)+C(i))-0.5*dx*g*gl-0.166*dx^2*(1-g^2-3*F)*cl))+F*((dx*gr-0.5*dx^2*g*cr)-(dx*gl-0.5*dx^2*g*cl))-k*C(i)*dt;
end
C = Cp;
end
  1 commentaire
AC_GBX
AC_GBX le 6 Nov 2020
Hey ummabb66,
please use the code insert function to display your code, so it can be understood. What is you exact problem?

Connectez-vous pour commenter.

Réponses (1)

Gautam
Gautam le 1 Juil 2025
Hello, ummaab66
The error id in the line with the expression
gr= (C(i+1)-C(i))/dx;
The array C has 252 elements and i goes from 3 to 252. So, when you try to access the element C(i+1) when i is 252, MATLAB is not able to find the element and throws the error.

Catégories

En savoir plus sur MATLAB Compiler dans Help Center et File Exchange

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by