a6ac08c662
Pass 2 of the implementation plan. Adds magnetic-field synthesis at arbitrary sensor locations, all in f64 for near-field stability per plan §7-1. Public API (re-exported from lib.rs): - dipole_field(&DipoleSource, sensor_pos) -> ([f64; 3], near_field_flag) Closed-form analytic dipole: B = (μ₀ / 4π r³)[3(m·r̂)r̂ − m] (Jackson 3e §5.6). - current_loop_field(&CurrentLoop, sensor_pos) -> (Vec3, flag) Numerical Biot–Savart over n_segments straight chords (default 64); flag fires if any chord midpoint < R_MIN_M (1 mm) of sensor. - ferrous_field(&FerrousObject, ambient_b, sensor_pos) -> (Vec3, flag) Linear induced moment m = χ·V·H_ambient (Cullity & Graham 2e §2), re-radiates as a dipole. - scene_field_at(&Scene, sensor_pos) -> (Vec3, flag) — aggregate. - scene_field_at_sensors(&Scene) -> Vec<(Vec3, flag)> — for every sensor. - R_MIN_M = 1 mm — near-field clamp constant. Pass 2 acceptance per plan §3 — n=8 RMS gate ≤ 0.5%. Test `dipole_n8_directions_within_half_percent_rms` independently recomputes the formula in-test rather than calling the implementation twice, so the gate guards against an implementation that accidentally agrees with a buggy reference. 7 new tests: - on-axis dipole matches B_z = μ₀ m / (2π z³) - equatorial dipole matches B_z = -μ₀ m / (4π r³) - n=8 directions RMS ≤ 0.5% — Pass 2 acceptance gate - on-axis current loop matches μ₀ I a² / [2(a²+z²)^(3/2)] - near-field r < 1 mm clamps to (0, flag=true) - zero-ambient ferrous object emits zero field - two opposite dipoles aggregate to zero at colocated sensor Validated: - cargo test -p nvsim → 19 passed (was 12; +7). - cargo test --workspace --no-default-features → 1,594 passed, 0 failed, 8 ignored (was 1,587; +7). - ESP32-S3 on COM7 streaming live CSI (cb #8900). Co-Authored-By: claude-flow <ruv@ruv.net> |
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| Cargo.toml | ||
| README.md | ||
README.md
nvsim
Deterministic Rust simulator for NV-diamond ensemble magnetometer pipelines.
nvsim models a forward-only magnetic sensing path:
scene
→ magnetic source synthesis
→ material attenuation
→ NV-ensemble response
→ digitisation
→ binary magnetic feature frames
→ deterministic SHA-256 witness
It is designed for ferrous-anomaly modeling, eddy-current sanity checks, synthetic magnetic traces, sensor education, and regression testing.
It is not a hardware-control stack, microscope simulator, full Hamiltonian solver, or claim of fT-level sensitivity. This crate does not control lasers, microwave sources, ADC hardware, or real NV sensors.
Deterministic in the strong sense: a simulator with explicit physics approximations, conjectural propagation defaults that are documented as such, a linear NV-ensemble readout proxy validated by Barry et al. Rev. Mod. Phys. 92, 015004 (2020) §III.A, and no hidden mocks.
Quick start
use nvsim::scene::{Scene, DipoleSource};
use nvsim::frame::{MagFrame, MAG_FRAME_MAGIC};
let mut scene = Scene::new();
scene.add_dipole(DipoleSource::new([0.0, 0.0, 0.5], [0.0, 0.0, 1e-6]));
scene.add_sensor([0.0, 0.0, 0.0]);
// Pass 2+ adds source synthesis, propagation, sensor, digitiser, pipeline.
Acceptance commitments (per implementation plan §5)
- Pipeline throughput: ≥ 1 kHz simulated samples per second of wall-clock on a Cortex-A53-class CPU.
- Determinism: same
(scene, seed)produces byte-identical proof-bundle output across runs and machines. - Noise floor reproduction: simulator with shot-noise OFF reproduces the analytical Biot–Savart result to ≤ 0.1% RMS.
- Lockin SNR floor: 1 nT @ 1 kHz vs 100 pT/√Hz floor → SNR ≥ 10 in 1 s.
Pass 1 (this build) ships only the scaffold + scene types + binary frame shape; the four acceptance numbers come online over Passes 2–6 per the plan.
Physics primary sources
- Jackson, Classical Electrodynamics 3e (1999), §5.4–5.8 — Biot–Savart, dipole field.
- Doherty et al., Phys. Rep. 528, 1 (2013) — NV ground-state Hamiltonian, ODMR transition.
- Barry et al., Rev. Mod. Phys. 92, 015004 (2020) — NV-ensemble sensitivity, Lorentzian lineshape.
- Wolf et al., Phys. Rev. X 5, 041001 (2015) — bulk-diamond pT/√Hz reference floor.
- Ortner & Bandeira, SoftwareX 11, 100466 (2020) — Magpylib reference implementation.
See docs/research/quantum-sensing/14-nv-diamond-sensor-simulator.md for context
and 15-nvsim-implementation-plan.md for the build spec.
Optional integrations
nvsim is a standalone leaf crate. RuView ecosystem integrations
(wifi-densepose-core frame alignment, ruvector-core trace compression,
etc.) land behind feature flags in follow-up passes once the core simulator
ships. None are required to use this crate.
License
MIT OR Apache-2.0 (matches workspace default).