Using ode45 to solve odes from a matrix
84 views (last 30 days)
Show older comments
Ashton Linney
on 23 Mar 2020
Commented: Ashton Linney
on 23 Mar 2020
This is the code I currently have. It works however I have had to manually input the four odes. (Line 8)
My question is, what code can I use to automate this part by using a matrix and a vector of y(i) variables?
The matrix would be [-f1 f1 0 0; 0 -f2 f2 0; 0 0 -f3 f3; v 0 0 -v]
Thank you!
%=====fx represents transition rate for degredation to next state=====
f1=0.5;
f2=0.5;
f3=0.2;
v=0;
%=====Sets the ordinary differential equations as a vector=====
f = @(t,y)[-f1*y(1)+v*y(4); -f2*y(2)+f1*y(1); -f3*y(3)+f2*y(2); f3*y(3)-v*y(4)];
%=====Sets time period=====
tspan = [0 30];
%=====Sets the initial state conditions as a vector=====
y0 =zeros(4,1);
y0(1) = 1;
%=====Calls the integrator=====
[t, y] = ode45(f,tspan,y0);
%=====Plots the results=====
plot(t,y(:,1),t,y(:,2),t,y(:,3),t,y(:,4))
legend('State 1','State 2','State 3','State 4','Location','best')
title('Probability of being in each state at time t.')
0 Comments
Accepted Answer
James Tursa
on 23 Mar 2020
Edited: James Tursa
on 23 Mar 2020
F = [-f1 f1 0 0; 0 -f2 f2 0; 0 0 -f3 f3; v 0 0 -v].';
f = @(t,y) F * y;
More Answers (0)
See Also
Categories
Find more on Ordinary Differential Equations in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!