Stochasm — Saving & sharing

Saving & sharing — the configuration format, per model

Saving & sharing

A Stochasm system is a single JSON document. The Export tab shows the running system's JSON (with an option to include the current lattice as a pinned snapshot, in single mode); copy it to a file. The Launcher's Import pastes one back — with exactly its settings. The presets are these same files, served from the app's presets/ folder.

Two of the models carry a rich enough structure to serialise: the Multi-Component Lattice and Patchy Discs (Ising and the single particle have no config export).

The envelope

Every config is the same extensible three-part shape, whatever the model:

Structure

Key	What it holds
`name`	A display name for the system (optional).
`model.type`	Which model — `multi_component_lattice` or `patchy_discs`. It routes a pasted config to the right model, and a preset file to its picker.
`model.configuration`	The model-specific structure — site types & rules, or the patchy design. Detailed per model below.
`snapshot`	An optional saved stage state — an object, so it can hold several pieces at once. Today only the lattice writes one (`snapshot.lattice`); omit it for a freshly-generated start.

The two sections below spell out each model’s configuration (and, where it has one, its snapshot); the complete field-by-field specification lives in the project README ("The model configuration format").

Multi-Component Lattice format

For a lattice config, model.type is "multi_component_lattice" and model.configuration holds the coordination number, the site types, and the rules. The saved initial state, when present, lives in snapshot.lattice.

configuration

Field	Meaning
`coordination_number`	4 (von Neumann) or 8 (Moore) — the neighbour shell.
`types[]`	The site-type palette (below).
`rules[]`	The transformation rules (below).

snapshot (optional)

Field	Meaning
`lattice`	A 2D array of type ids whose shape is the lattice size — a pinned initial state. Omit the whole `snapshot` and the Builder's size slider decides the dimensions, seeded from each type's `default_initial_relative_amount`.

Each type

Field	Meaning
`name`, `color`	Label and hex colour.
`immobile`	true ⇒ swap rules cannot displace it.
`masquerade_as`	Type id this one imitates for facilitation counting (or −1 = none).
`field`	The type's energetic bias, in k_BT.
`default_initial_relative_amount`	Its relative share when the lattice is seeded randomly.
`persistence`, `alpha`	Display-only trail decay and opacity.

Each rule

Field	Meaning
`kind`	One of irreversible_flip · reversible_flip · swap · site_site_interaction.
`a`, `b`	The two endpoint type ids (−1 = the any-site wildcard).
`param`	The attempt-weight (flips/swaps) or interaction energy (site-site).
`disabled`, `ignore_energetics`	Rule enable flag; bypass all fields & interactions.
`facilitation` (optional)	A `{ "number": n, "site": t }` node — the flip needs n neighbours of type t.

Patchy Discs format

For a patchy config, model.type is "patchy_discs" and model.configuration describes the patch types, the disc species, and the bond rules. The disc count and packing fraction are chosen in the Builder (defaulting to 100 discs at φ 0.5) — like the lattice size, they are not stored in the config. Patchy has no stage snapshot yet, so it omits snapshot.

configuration

Field	Meaning
`patch_bond_stiffness`	The spring constant of every formed patch bond.
`patch_types[]`	The bonding patch species (below).
`species[]`	The disc species (below).
`rules[]`	The bond rules (below).

Each patch type & species

Field	Meaning
patch type: `name`, `color`	Label and hex colour of a bonding patch.
species: `name`, `color`	Label and hex colour of a disc species.
`radius`, `relative_abundance`	Disc size and its share of the box population.
`patches[]`	Each rim patch as `{ "angle", "patch_type" }` — the angle in degrees, the patch type an index into `patch_types`.

Each rule

Field	Meaning
`name`	A label for the bond rule.
`a`, `b`	The two patch-type indices this rule lets bond.
`strength`	The bond strength ε, in k_BT.
`attempt_rate`	Bind/unbind attempts per MD step, per patch.
`disabled`	Rule enable flag.