Run safety: size guard & Stop
Simulations run in your browser, in a background worker. A very large run (many replications × a long horizon × a big model) can use a lot of memory and time. Two features keep that under control: a pre-run size guard that warns before a heavy run, and a Stop button that interrupts any run in progress.
Pre-run size guard
Before an experiment or a recording starts, the Studio estimates the run's cost from replications × horizon × node count and compares it against a budget derived from your device's memory. If the run looks heavy, you get a dialog instead of a frozen tab:
This run may strain your device replications 1000 → 50, horizon 100000 → 50000
[Use lighter settings] · [Run anyway] · [Cancel]
- Use lighter settings halves the replications and horizon (respecting the warm-up rule) and runs with those — and the run-settings form updates to match.
- Run anyway runs unchanged.
- Cancel backs out.
A run the guard considers fine starts immediately, with no dialog. The estimate still works on browsers that don't report device memory (it falls back to a conservative default budget).
Optimize is guarded too
The optimizer runs many simulations — one per candidate configuration — so its cost is the per-run cost amplified by the search budget: population × iterations × replications × horizon × node count. Before an optimization starts, the Studio estimates that total against the same device-memory budget and, if it looks heavy, shows the guard:
This run may strain your device population 40 → 20, iterations 15 → 7
[Use lighter settings] · [Run anyway] · [Cancel]
Here Use lighter settings halves the search budget (population and iterations) rather than the run settings — a smaller search that still explores the same design space, just less exhaustively. A default optimization on a small model starts immediately with no dialog; only large models or long horizons trip it.
Stop a running simulation
While an experiment, optimization, or recording is running, a Stop strip appears above the tabs:
Running experiment… [Stop]
Click Stop to terminate the run immediately. The partial run is discarded (stopping is a hard cancel, not a pause) — re-run with lighter settings if it was too big. Before this, none of the three run types could be interrupted from the UI at all.
Turning the guard off
The Run size guard toggle in the app menu disables the pre-run dialog entirely. The Stop button is always available regardless of the toggle.
What this is not (and why)
This is a pre-run guard plus a Stop button, not a live memory monitor. The Studio runs sims in Web Workers, and the browser API for reading JS heap (performance.memory) does not exist inside a worker — so a web page cannot watch a running sim's actual memory. The only cross-worker memory API (measureUserAgentSpecificMemory()) requires site-wide cross-origin isolation that would break the Google sign-in popup, so it's deferred. The guard estimates before the run (where it can act) and Stop lets you bail out during one.