Error in ODE 45: MYODE must return a column vector.
4 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
I am trying to discretize a system of PDEs with a finite difference scheme and solve the resulting ODE system with ODE45:
PDE Solver code:
global N;global dx;
global a11; global a12; global a22; global a21;
a11=1;a12=1; a22=1;a21=1;
dx = .05;
X = -2:dx:2;
N = length(X);
tspan = [0 2];
u = ones(1,N);
v = 2*ones(1,N);
%Initial Data
%%
y0 = [u,v];
%%
% Solve ODE
[t,y] = ode45(@myODE, tspan, y0);
myODE code:
function dy = myODE(~,y)
global N;
global dx;
global a11; global a12; global a22; global a21;
u=y(1:N);
v = y((N+1):2*N);
du = zeros(size(u));
dv = zeros(size(v));
du(1) = (2*a11*(u(2)-u(1)))/(dx^2)+a12*(u(1)*v(2)-u(2)*v(1)-u(1)*v(1)-u(2)*v(2))/(dx^2);
dv(1) = 2*a22*(v(2)-v(1))/(dx^2)+a21*(v(1)*u(2)-v(2)*u(1)-v(1)*u(1)-v(2)*u(2))/(dx^2);
du(N) = 2*a11*(u(N-1)-u(N))/(dx^2)+a12*(u(N)*v(N-1)-u(N-1)*v(N)-u(N)*v(N)-u(N-1)*v(N-1))/(dx^2);
dv(N) = 2*a22*(v(N-1)-v(N))/(dx^2)+a21*(v(N)*u(N-1)-v(N-1)*u(N)-v(N)*u(N)-v(N-1)*u(N-1))/(dx^2);
for i=2:N-1
du(i) = a11*(u(i+1)-u(i)+u(i-1))/(dx^2)+a12*(u(i)*v(i+1)-u(i-1)*v(i)-u(i)*v(i)-u(i-1)*v(i-1))/(dx^2);
dv(i) = a22*(v(i+1)-v(i)+v(i-1))/(dx^2)+a21*(v(i)*u(i+1)-v(i-1)*u(i)-v(i)*u(i)-v(i-1)*u(i-1))/(dx^2);
end
dy = [du,dv];
0 commentaires
Réponse acceptée
Plus de réponses (0)
Voir également
Catégories
En savoir plus sur Ordinary Differential Equations dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!