how to stop ode45 when one of states reach certain value
311 ビュー (過去 30 日間)
古いコメントを表示
[x_dot] =derivative(t, x)
x is states [x(1).....x(4)] I need to stop the integration when x(3) reaches 0.1 when the integration stop record (t)
0 件のコメント
採用された回答
Jan
2016 年 5 月 4 日
Opt = odeset('Events', @myEvent);
[T, Y] = ode45(@YourFun, T, Y0, Opt);
function [value, isterminal, direction] = myEvent(T, Y)
value = (Y(3) == 0.1);
isterminal = 1; % Stop the integration
direction = 0;
7 件のコメント
Walter Roberson
2023 年 10 月 20 日
In the call
[T, Y] = ode45(@YourFun, T, Y0, Opt);
the input T is the timespan to integrate over. It is a vector that must have at least two elements, but may have more. If it has two elements then ode45() will decide by itself what times to output information at; if it has more than two elements then ode45() will output information at the times given in the vector.
その他の回答 (2 件)
Walter Roberson
2016 年 5 月 4 日
編集済み: Walter Roberson
2017 年 9 月 13 日
You need to add an event function. See http://www.mathworks.com/help/matlab/ref/odeset.html#input_argument_d0e709348
Gustavo Lunardon
2020 年 8 月 17 日
This is confusing. In matlab help it says: An event occurs when value(i) is equal to zero. All answers in this post make it value = 1 for the event to happen. Are the answers outdated somehow?
1 件のコメント
Walter Roberson
2020 年 8 月 19 日
This is a valid concern.
value = (X(8) == 0.05 ) and (Y(3) == 0.1) would happen rarely, when the values were bit-for-bit identical to the representation of 0.05 and 0.1 . One bit different in the representation and the condition will not fire. Better is to write x(8) - 0.05 or 0.05 - x(8), and Y(3)-0.1 or 0.1-Y(3) -- zero crossings can be detected for those.
参考
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!