Stochasm

Tips & troubleshooting

• WebGL2 is required. Every modern browser has it; if the stage reports a WebGL problem, update your browser or enable hardware acceleration.
• On a phone? The simulator itself needs a desktop or laptop browser (phones get a landing page instead), but this guide (and the Gallery) works fine on mobile, so you can read up before you're back at a real keyboard.
• Presets need a web server. Opening stochasm.html straight from disk (file://) blocks the preset list: a browser security restriction on fetch, not a bug. Paste-import still works, and the hosted app is unaffected.
• Play greyed out after launching an ensemble? It enables the moment all replicas finish seeding, a few seconds for the largest ensembles.
• Performance levers: the Compiled C Core and worker count (Builder), MC or MD speed (both have an Auto-tune checkbox that finds the batch size past which more steps buy nothing but slower graphics), the measurement rate (ensembles: sampling observables less often is the single biggest win for large lattices), system size and ensemble size, and the observable group toggles in the Compute tab — Pair correlation and Union-Find are the heavy ones for the lattice model, and for Patchy Discs the Contacts, both Union-Find groups and Polymer chains. Patchy also has the Cell Lists switch (Builder): leave it on except for an A/B comparison — it is an O(n) neighbour search, bit-identical to the brute-force pair loop.
• The two FPS numbers are honest: gfx is drawing, sim is physics. A paused simulation shows sim 0 fps by design.
• Occupancy edits not showing? Occupancy is a Builder control (it re-seeds the preview live). The one exception: while an imported lattice snapshot is pinned, occupancy edits defer; a green note in the Builder’s Site Types list says the new values apply whenever the lattice is next seeded randomly (uncheck the snapshot in System to seed randomly now).
• Lost a floating window? Start Fresh resets every window to its home position.