Abort iterations upon a condition on the cost function

[thibc81]

Hello

I am trying to figure out the terminate function so as to abort the optimization if the cost function returns a certain value.
Is this possible? I couldn't find an example in the doc or on the git examples folder.

Thanks!

[stefan-k]

Are you using one of the available solvers or are you implementing your own?

The default implementation of terminate_internal of the Solver trait automatically checks if a target cost is reached.

You can set the target cost via the target_cost method of IterState (or PopulationState, depending on which solver you are using), somewhat like this:

let res = Executor::new(cost, solver)
        .configure(|state| state.param(init_param).max_iters(10).target_cost(0.0))
        .run()?;

EDIT: If you are implementing your own solver you will get this feature "for free" unless you overwrite terminate_internal.

[thibc81]

Thank you for your answer.
I am using PSO, in fact target_cost is effectively what I needed, thanks again.

[stefan-k]

I added a little note about target_cost(...) to the example in the book.