how to stop dde23 when one of states reach certain value?
1 view (last 30 days)
Show older comments
sourabh mittal
on 18 Sep 2018
Commented: sourabh mittal
on 18 Sep 2018
I want to stop dde23 when i am geeting 99% close to steady state and extract saturation time. I have written code of my system and then call dde23 to solve it. problem is am not able to terminate code when saturation is reached.
0 Comments
Accepted Answer
Torsten
on 18 Sep 2018
Use the "Events" option of dde23.
Best wishes
Torsten.
3 Comments
Torsten
on 18 Sep 2018
function main
tstart = 0.0;
tend = 100.0;
options = ddeset('Events',@events);
sol = dde23(@ddex1,2,[0.7],[tstart tend],options);
tevent = sol.xe(1) % time of 99 % saturation
tint = linspace(tstart,tevent,20);
yint = deval(sol,tint);
plot(tint,yint)
end
function dydt = ddex1(t,y,Z)
ylag = Z(:,1);
dydt = y*ylag*(1-y);
end
function [value,isterminal,direction] = events(t,y,Z)
value(1) = y(1)-0.99;
isterminal(1) = 1;
direction(1) = 1;
end
More Answers (1)
Walter Roberson
on 18 Sep 2018
Perhaps relax RelTol ?
The normal way of stopping early is to use an event function that examines the current state and decides whether to terminate early.
However, I do not know how you would determine whether saturation has occurred. If it requires examining previous states, such as to determine that the change in values is small enough, then event functions cannot do that (but in that particular situation, changing tolerances can help.)
0 Comments
See Also
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!