Event function for ODE solver

Hi, I am using ode15s and would like to ask how to use Events function. So basically I need to stop the ODE solver iteration before the given time span, to be exact when the values of y equals to certain values e.g y(i)=0.01 (my y vector stores more than one variable) I have browsed a lot of questions here and all seems suggest the ballode function, but is there anyone who can kindly guide me step by step on how to use it?

Thanks!

Answer 1

[Mahmudul Hasan]

Its easy. Just set the value = y(i)- 0.01 in event function, please. Like:

[value isterminal direction] = event_function(t,y)

value = y(i)-0.01; isterminal=1; direction = 0;

Hope this helps you a lot.

Thanks Mahmudul

Answer 2

[Jan]

This is described in doc ode45 and doc odeset.

See http://www.mathworks.com/help/techdoc/ref/odeset.html#f92-1017470.

[Zhenke Xi]

example!example!man!no exact example in your link!

[Steven Lord]

There are a couple examples in the documentation.

[Jan]

@Zhenke Xi: Calm down. If you want to ask for an example, simply ask for an example.

Open the first link, search for "For more information, see ODE Event Location" and click on the link (it is and the 2nd last paragraph of "Description").

Alternatively you can ask an internet search engine for "Matlab ode event function example". This requires less exclamation marks.