rust-e-sim

High-performance, purely functional circuit simulation kernels in Rust.

rust-e-sim is a professional-grade circuit simulation engine designed for low-latency transient analysis. It provides the core numerical routines required for SPICE-like simulation, specifically optimized for WebAssembly integration with modern reactive frameworks like Svelte 5.

Features

• Modified Nodal Analysis (MNA): Robust matrix formulation for circuit topology.
• Sparse LU Solver: Optimized linear algebra for small-to-medium circuits (N ≤ 100).
• Newton-Raphson Iteration: Convergent solver for nonlinear devices (diodes, transistors).
• Adaptive Integration:
  • Backward Euler: Robust first-order integration.
  • BDF-2 (Gear-2): High-accuracy second-order integration.
• Advanced Semiconductor Models:
  • Gummel-Poon BJT: Standard transistor model with high-injection and Early effect.
  • Shockley Diode: Standard diode model with Zener breakdown.
  • SPICE pnjlim: Voltage limiting for numerical stability in nonlinear regions.
• State Persistence: Full serialization/deserialization of simulation state via serde.
• High-Performance WASM Bridge: Minimal-copy interface for browser-based simulation.

Architecture

The project is split into two main components:

rust-e-sim-core

The pure-Rust simulation engine. It is no_std-compatible (with alloc) and handles:

• Netlist compilation and node reordering (Minimum Degree).
• Sparse and dense linear solvers.
• Nonlinear element stamping.
• Transient time-stepping logic.

rust-e-sim-wasm

A wasm-bindgen wrapper that exposes the core engine to JavaScript/TypeScript.

• Optimized for the browser's AudioWorklet or main thread.
• Provides a Simulator class with a simple API for building and stepping circuits.
• Supports seamless "pot-turn" scenarios where component values are updated without resetting the simulation progress.

Getting Started

Prerequisites

• Rust (latest stable)
• wasm-pack (for building the WASM bridge)

Building

To build the core library:

cargo build -p rust-e-sim-core

To build the WASM bridge:

cd rust-e-sim-wasm
wasm-pack build --target web

Testing

The project includes a comprehensive test suite covering numerical parity and physical correctness:

cargo test --all-targets

Integration with Svelte 5

rust-e-sim is designed to work seamlessly with Svelte 5 Runes. You can wrap the Simulator state in a $state rune and use get_full_state() / set_full_state() for persistent session management.

import init, { Simulator } from './pkg/rust_e_sim_wasm.js';

await init();
const sim = new Simulator(0); // Ground node ID = 0
sim.add_voltage_source("V1", 1, 0, 5.0);
sim.add_resistor("R1", 1, 2, 1000.0);
sim.add_capacitor("C1", 2, 0, 1e-6, 0.0);

if (sim.compile()) {
  const result = sim.step(1e-6); // Step 1 microsecond
  console.log("Node 2 voltage:", sim.node_voltage(2));
}

License

MIT OR Apache-2.0