how to stop dde23 when one of states reach certain value?
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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.
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Torsten
2018년 9월 18일
Use the "Events" option of dde23.
Best wishes
Torsten.
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Torsten
2018년 9월 18일
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
추가 답변 (1개)
Walter Roberson
2018년 9월 18일
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.)
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