[Users] Automatic termination trigger mid-run

[Jordan Nicoules]

Hi Erik,


Thank you for your reply! I know of CCTK_TerminateNext, I actually use it in one of my thorns (so I could hack it to achieve what I want). In fact, a call to this function is what I would add to Trigger.


My point is more: with the existing thorns, is there a way to terminate a simulation while it's running (and before its expected end based on final time/iteration), with a parfile directive, without:

- manually editing the termination file

- reaching walltime

- having NaNs

- and such edge cases.


Something that would be like:

```

Trigger::Trigger_Checked_Variable    [0] = "ADMBase::lapse"
Trigger::Trigger_Reduction           [0] = "minimum"
Trigger::Trigger_Relation            [0] = "<"
Trigger::Trigger_Checked_Value       [0] = 0.2
Trigger::Trigger_Reaction            [0] = "terminate"    # <-- This doesn't exist as far as I understand
```

Thanks,

Jordan

________________________________
From: Users <users-bounces at einsteintoolkit.org> on behalf of Erik Schnetter via Users <users at einsteintoolkit.org>
Sent: Thursday, June 4, 2026 14:57
To: users at einsteintoolkit.org
Subject: Re: [Users] Automatic termination trigger mid-run


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You can call the function `CCTK_TerminateNext`, which will stop the simulation gracefully after the current iteration finishes. This is built-in, you do not need a special thorn for this.

This is how TerminationTrigger is implemented: It calls this function when a certain file is created.

-erik

On Jun 4, 2026, at 09:31, Jordan Nicoules via Users <users at einsteintoolkit.org> wrote:

Dear all,

I was wondering if there was a built-in way to trigger the termination of a simulation when something specific happens, along the lines of what Trigger does to steer quantities. From what I understand, Trigger does not offer that possibility, and TerminationTrigger checks either a file or a time limit. What I'm considering would be more along the lines of "an apparent horizon is found so trigger termination", in order to steer some parameters at recovery.

If there's no such explicit way, I'm happy to try to implement that in Trigger. I actually have ideas of other small improvements to Trigger that I could try contributing as well (namely, increase the maximum number of triggers and allow one trigger to have multiple consequences at once).

Unfortunately I won't be able to join the weekly call today to discuss this directly.

Best,

Jordan
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