How to know the step time inside the function that integrated by ode45?
3 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
Mohamed Aburakhis
am 24 Jun. 2016
Kommentiert: Walter Roberson
am 25 Jun. 2016
I have
x0=1;
[t,x] = ode45(@My_Fun,[0:0.01:10],x0);
and My_Fun is
function x_dot =My_Fun(t, x)
Here %%%
%%I want to know the instantaneous step time %%%
What are t(now) and t(next) %%%
x_dot(1)=2/m-x;
1 Kommentar
Akzeptierte Antwort
Roger Stafford
am 25 Jun. 2016
Bearbeitet: Walter Roberson
am 25 Jun. 2016
You might be interested in a comment made in
“If tspan contains two elements, [t0 tf], then t contains the internal evaluation points used to perform the integration.” It depends on whether you believe this in a literal sense or that it is merely an "approximate" truth.
0 Kommentare
Weitere Antworten (1)
Walter Roberson
am 25 Jun. 2016
You cannot know the t of the next step. ode45() uses adaptive time steps, so the next time step will depend upon will depend upon the outcome of this step. Also, if your x is not a scalar, then the next ode45 call might have the same time as the current one, but with different boundary conditions (x), so that it can explore the change along the other dimensions.
1 Kommentar
Walter Roberson
am 25 Jun. 2016
None of the ode* routines permit fixed time step. They do allow setting a guideline for the initial step, and they do allow setting the maximum step, but they do not allow the step size to be fixed.
Siehe auch
Kategorien
Mehr zu Ordinary Differential Equations finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!