How to Get Second Derivative in ode45 solver?

16 次查看（过去 30 天）
ercan duzgun
ercan duzgun 2022-7-21
评论： ercan duzgun 2022-7-25
Dear MATLAB users;
I would like to solve a nonlinear equation using ode45. ode45 solver provides time (t), position (x), velocity (x_dot) .
I need acceleration , second derivative (x_dotdot). However, I can't get x_dotdot as output from ode45. I looked at the options/parameteres of ode45. I couldn't find there information about that.
I know that I can get x_dotdot, using x_dot numerically by subtraction of xdot(step n) and xdot(n+1 step), by typing extra codes. But I just wondered if it is possible to do it without writing codes? Is it possible to get second derivative (x_dotdot) of ode45 by using options in ode45?
Thanks in advance.
Ercan

请先登录，再回答此问题。

采纳的回答

Sam Chak
Sam Chak 2022-7-21
Ran in:
Hi @ercan duzgun
You don't need to..., because you can see the elephant in the room (not sure if this is the correct metaphorical idiom; I'm not good at English idioms).
Say the system is given by .
f = @(t, x) [x(2); - 2*x(2) - x(1)];
[t, x] = ode45(f, [0 10], [1 0]);
xddot = - 2*x(:,2) - x(:,1); % the acceleration, second derivative (x_dotdot)
plot(t, xddot), grid on, xlabel('t')
  1 个评论
ercan duzgun
ercan duzgun 2022-7-25
Dear @Sam Chak thank you very much for your response. Really, you are right, it was really the elephant in the room :) . I am surprised how I didn't notice this very obvious thing. Thank you for showing me, explaining me in detailed.
Kind regards,
Ercan

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Programming 的更多信息

标签

产品


版本

R2022a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by