Crate pantometry 

pantometry: physics for simulated worlds, in one dependency.

A facade over the workspace. Nothing is implemented here — the point is that a consumer writes pantometry = "0.16" rather than naming eleven crates, and that the integration tests which need two domains at once have somewhere to live.

use pantometry::prelude::*;

// A lamp, a filter, and the question that needs both.
let lamp = SpectralPower::new(
    Spectrum::blackbody(3200.0),
    Power::w(1.0),
    VISIBLE_RANGE,
);
let green = Spectrum::bands(vec![[500.0, 560.0]], 0.95, 0.0);
let through = lamp.through(&green);
assert!(through < lamp.total());

Start here

Three ideas carry the whole library.

1. Units are types. Dimensions live in the type, so Length + Time does not compile. One place may hold a factor of a thousand — a unit-bearing constructor — and to_si() is the only way back to a bare f64.
2. A domain is anything that steps. Domain requires name and step; everything else has a default. Override ledger so the audit has something to check.
3. Domains never call each other. They meet on Exchange, a bus of named channels carrying SI amounts — joules, not watts. A ledger says what you are holding, not what has passed through you.

And the reason to pick this over a general-purpose engine: conservation is audited every step, so a wrong model does not run quietly. advance returns a Violation naming the quantity, the site, and the before and after — a correctness signal you can act on without a human noticing first.

energy destroyed at simulation: 5.000000e2 became 4.995000e2,
a relative change of 1.000e-3 against a tolerance of 1.000e-9

Be clear about the limit: the audit catches quantities appearing or vanishing, amounts left unclaimed on the bus, and fluxes disagreeing face by face across a shared boundary. It does not catch a model that is internally consistent and physically wrong — publish a power where a joule was wanted and both sides agree perfectly about a number off by 1/dt. For that, check against something the code did not compute: a closed form, an exact limit, or a convergence rate.

cargo run --example agents_quickstart is all of the above as a running program, including a deliberate leak so the failure is visible. AGENTS.md in the repository is the one-page version.

The dependency rule

pantometry-units       no dependencies but glam and serde
pantometry-core        depends on units          the kernel: what evolves, what it conserves
pantometry-optics      depends on core   ┐
pantometry-thermal     depends on core   │
pantometry-mechanics   depends on core   ├ one crate per physics, and none knows another
pantometry-acoustic    depends on core   │
pantometry-molecular   depends on core   │
pantometry-electrical  depends on core   ┘
pantometry-scene       depends on core           where things are, and what a run looks like
pantometry-view        depends on scene          how to draw that, chosen by the data's shape
pantometry             depends on all of them

None of the ten domains knows about any of the others. They meet on the kernel’s Exchange, and each one that arrived left the others untouched — which is the claim the split was made to test, now held six times.

scene and view are layers up rather than domains, and they are bound by the same rule from the other side: neither names a domain. A physics that arrives tomorrow is captured without scene being edited, and drawn without view being edited, because the scene asks each domain what it offers and the view dispatches on the shape of what came back. ARCHITECTURE.md is the long version.

Re-exports

pub use pantometry_acoustic as acoustic;

pub use pantometry_core as core;

pub use pantometry_elastic as elastic;

pub use pantometry_electrical as electrical;

pub use pantometry_em as em;

pub use pantometry_fluid as fluid;

pub use pantometry_mechanics as mechanics;

pub use pantometry_molecular as molecular;

pub use pantometry_optics as optics;

pub use pantometry_porous as porous;

pub use pantometry_quantum as quantum;

pub use pantometry_scene as scene;

pub use pantometry_shape as shape;

pub use pantometry_thermal as thermal;

pub use pantometry_units as units;

pub use pantometry_view as view;

Modules

prelude

Everything most simulations need, in one use.