Error while solving a coupled system of ODE
1 回表示 (過去 30 日間)
古いコメントを表示
I am trying to solve a system of 6 coupled ODE my function works but I dont know why calling ode45 doesnt work.
My function is:
function [dxdt] = DM_bacteria(t,x,sigma,r,f,s,epsilon,omega,gamma12,g12)
dxdt(4)=x(4)*(r(4)*(1-(sigma(4,4)*x(4)+sigma(4,1)*x(1)+sigma(4,2)*x(2)+sigma(4,3)*x(3))/r(4))-f(4,1)*x(5)-f(4,2)*x(6))+s(4)
dxdt(5)=x(5)*(-epsilon(1)*(1+(omega(1,1)*x(5)+omega(1,2)*x(6))/epsilon(1))-g12*x(5)+beta(1,1)*f(1,1)*x(1)+beta(2,1)*f(2,1)*x(2)+beta(3,1)*f(3,1)*x(3)+beta(4,1)*f(4,1)*x(4))
dxdt(6)=x(6)*(-epsilon(2)*(1+(omega(2,2)*x(6)+omega(2,1)*x(5))/epsilon(2))-gamma12*g12*x(5)+beta(1,2)*f(1,2)*x(1)+beta(2,2)*beta(2,1)*f(2,2)*x(2)+beta(3,2)*f(3,2)*x(3)+beta(4,2)*f(4,2)*x(4))
dxdt(1)=x(1)*(r(1)*(1-(sigma(1,1)*x(1)+sigma(1,2)*x(2)+sigma(1,3)*x(3)+sigma(1,4)*x(4))/r(1))-f(1,1)*x(5)-f(1,2)*x(6))+s(1)
dxdt(2)=x(2)*(r(2)*(1-(sigma(2,2)*x(2)+sigma(2,1)*x(1)+sigma(2,3)*x(3)+sigma(2,4)*x(4))/r(2))-f(2,1)*x(5)-f(2,2)*x(6))+s(2)
dxdt(3)=x(3)*(r(3)*(1-(sigma(3,3)*x(3)+sigma(3,1)*x(1)+sigma(3,2)*x(2)+sigma(3,4)*x(4))/r(3))-f(3,1)*x(5)-f(3,2)*x(6))+s(3)
end
The script :
sigma=ones(4,4)
f=ones(4,2)
g12=1
gamma12=2
beta=ones(4,2)
omega=ones(2,2)
epsilon=[4,2]
s=[0 0 0 0]
x0=[600 600 600 600 600 600]
t = [0 20];
r=[1 2 3 4]
t=linspace(0,20,1000)
[dxdt] = DM_bacteria(t,x0,sigma,r,f,s,epsilon,omega,gamma12,g12)
[t,x]=ode45(@DM_bacteria,t,x0)
I got error :(I have all the argument in the function)!!
Not enough input arguments.
Error in DM_bacteria (line 3)
dxdt(4)=x(4)*(r(4)*(1-(sigma(4,4)*x(4)+sigma(4,1)*x(1)+sigma(4,2)*x(2)+sigma(4,3)*x(3))/r(4))-f(4,1)*x(5)-f(4,2)*x(6))+s(4)
Error in odearguments (line 90)
f0 = feval(ode,t0,y0,args{:}); % ODE15I sets args{1} to yp0.
Error in ode45 (line 115)
odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);
Error in DynamicalModelBactera (line 14)
[t,x]=ode45(@DM_bacteria,t,x0)
0 件のコメント
採用された回答
Star Strider
2019 年 11 月 17 日
Your ‘DM_bacteria’ function must return a column vector output.
This worked when I ran it just now:
function [dxdt] = DM_bacteria(t,x,sigma,r,f,s,epsilon,omega,gamma12,g12)
dxdt(4,:)=x(4)*(r(4)*(1-(sigma(4,4)*x(4)+sigma(4,1)*x(1)+sigma(4,2)*x(2)+sigma(4,3)*x(3))/r(4))-f(4,1)*x(5)-f(4,2)*x(6))+s(4);
dxdt(5,:)=x(5)*(-epsilon(1)*(1+(omega(1,1)*x(5)+omega(1,2)*x(6))/epsilon(1))-g12*x(5)+beta(1,1)*f(1,1)*x(1)+beta(2,1)*f(2,1)*x(2)+beta(3,1)*f(3,1)*x(3)+beta(4,1)*f(4,1)*x(4));
dxdt(6,:)=x(6)*(-epsilon(2)*(1+(omega(2,2)*x(6)+omega(2,1)*x(5))/epsilon(2))-gamma12*g12*x(5)+beta(1,2)*f(1,2)*x(1)+beta(2,2)*beta(2,1)*f(2,2)*x(2)+beta(3,2)*f(3,2)*x(3)+beta(4,2)*f(4,2)*x(4)) ;
dxdt(1,:)=x(1)*(r(1)*(1-(sigma(1,1)*x(1)+sigma(1,2)*x(2)+sigma(1,3)*x(3)+sigma(1,4)*x(4))/r(1))-f(1,1)*x(5)-f(1,2)*x(6))+s(1);
dxdt(2,:)=x(2)*(r(2)*(1-(sigma(2,2)*x(2)+sigma(2,1)*x(1)+sigma(2,3)*x(3)+sigma(2,4)*x(4))/r(2))-f(2,1)*x(5)-f(2,2)*x(6))+s(2);
dxdt(3,:)=x(3)*(r(3)*(1-(sigma(3,3)*x(3)+sigma(3,1)*x(1)+sigma(3,2)*x(2)+sigma(3,4)*x(4))/r(3))-f(3,1)*x(5)-f(3,2)*x(6))+s(3);
end
sigma=ones(4,4);
f=ones(4,2);
g12=1;
gamma12=2;
beta=ones(4,2);
omega=ones(2,2);
epsilon=[4,2];
s=[0 0 0 0];
x0=[600 600 600 600 600 600];
t = [0 20];
r=[1 2 3 4];
t=linspace(0,20,1000);
% [dxdt] = DM_bacteria(t,x0,sigma,r,f,s,epsilon,omega,gamma12,g12)
[t,x]=ode45(@(t,x)DM_bacteria(t,x,sigma,r,f,s,epsilon,omega,gamma12,g12),t,x0);
figure
plot(t, x)
grid
ylim([-10, 10])
Experiment to get different results.
2 件のコメント
Star Strider
2019 年 11 月 17 日
Your system does not appear to be ‘stiff’, and ode45 had no problems with it. I would just continue with ode45, unless the parameters change significantly in their relative magnitudes and the system becomes ‘stiff’.
その他の回答 (0 件)
参考
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!