Stream: helpdesk (published)

Topic: [JuliaReach] How to specify nonlinear guard conditions?

ZihMing (Jul 28 2025 at 15:17):

I've recently started using JuliaReach for my research on hybrid systems, and I'm having trouble specifying nonlinear guard conditions for mode transitions.
I'm following the tutorial and using the @system macro to define each mode of the hybrid system. Now, suppose I have a mode with a guard condition like

$$P: x\leq y^2$$

or, more generally,

$$x\leq y^2 \lor x\geq z^3$$

How can I express this as the constraint in the @system macro? Are there better or recommended ways to handle nonlinear guard conditions in JuliaReach?
Any pointers would be appreciated!

jar (Jul 28 2025 at 17:15):

For what it's worth, Zulip is relatively underused, so if you don't get a reply here, you might get more traction on https://discourse.julialang.org/

Mason Protter (Jul 28 2025 at 17:32):

Yeah, I tried looking into this to see if I could help but it wasn't clear to me how it works. If someone from JuliaReach is here they'll probably help but otherwise Discourse is a good bet.

ederag (Jul 28 2025 at 18:25):

Or in the zulip #juliareach channel ?

jar (Jul 28 2025 at 19:19):

Oh, that seems better!

Christian Schilling (Jul 28 2025 at 20:53):

@ZihMing the short answer is that this is not supported :(

ZihMing (Jul 29 2025 at 03:14):

Thanks so much for all the suggestions and clarifications! I’ve followed up on the recommended channels to gather more information about JuliaReach :)

Christian Schilling (Jul 29 2025 at 05:55):

@ZihMing the slightly longer answer is that you can code it up yourself by using a nonconvex set representation (a taylor model), but it is not easy. there is an example here for the intersection with a circle
if you have questions about that, i suggest to continue the discussion in the other channel

Marcelo (mforets) (Jul 29 2025 at 15:30):

For what it's worth, Zulip is relatively underused, so if you don't get a reply here, you might get more traction on https://discourse.julialang.org/

i wish there was a way to get email notification on Julia Discourse keyword names, eg. notify me of any new post has "juliareach" on it. is that possible already?

Last updated: Aug 14 2025 at 04:51 UTC