Dune

SPICE, reborn in Rust. Dune is a faithful rewrite of Berkeley's SPICE3f5 circuit simulator: the same netlists, the same defaults, the same numbers — validated circuit by circuit against ngspice — with a clean engine you can call from Python, R, JavaScript or C.

Site: milkway.github.io/dune · Examples gallery — every corpus circuit, simulated · Known differences

What's inside

• Every SPICE3f5 device and analysis: R C L K, V/I sources, E F G H, diode, BJT (Gummel–Poon), MOS levels 1–6, BSIM1/2, JFET, MESFET, switches, ideal and lossy (LTRA) transmission lines, .subckt — and .OP .DC .AC .TRAN .PZ .NOISE .DISTO .TF .SENS. Plus BSIM3v3 and S-parameter analysis (.sp) from modern ngspice.
• Oracle-tested: nothing ships until every corpus circuit matches pinned ngspice-47 goldens point by point, at SPICE's own tolerances (reltol/abstol/vntol). Deliberate divergences are documented in corpus/KNOWN_DIFFS.md, each behind a measured gate.
• Schematics in, waveforms out: Dune reads figures written in rpic's pic language and extracts runnable decks (dune pic figure.pic); the same engine powers the Simulate panel in rpic Studio, all client-side WebAssembly.
• Rawfiles in SPICE3's own binary and ASCII formats, so existing viewers read them unchanged.
• A more accurate transient by default: .tran integrates with TR-BDF2, an L-stable method that does not ring and, on the corpus, is closer to the converged answer than the trapezoidal rule at the same step; a switch flips at the instant its control crosses the threshold, not at the first timepoint past it. .options compat=spice3 restores the SPICE3f5 defaults (the trapezoidal rule, switches on the grid), which is what the ngspice oracle checks.

Install

# Python — PyPI (polars DataFrames, zero-copy numpy; module `import spice`)
pip install spice3

# JavaScript / WebAssembly — npm (runs in the browser)
npm install @strategicprojects/dune-sim

# R — tidy tibbles (CRAN submission planned)
Rscript -e 'remotes::install_github("milkway/dune", subdir = "r")'

# Rust library — crates.io (dune-netlist, dune-raw, dune-core, dune-pic)
cargo add dune-core dune-netlist

# CLI — from source (Rust 1.88+)
git clone https://github.com/milkway/dune && cd dune && cargo build --release

The Rust crates are 0.x: the public API of dune-core may change between minor versions.

import spice

run = spice.simulate("""
step into a series rlc
V1 in 0 PULSE(0 1 0 1n 1n 1 2)
R1 in n1 60
L1 n1 out 1m
C1 out 0 1n
.tran 0.1u 40u
.end
""")
run.plots[0].frame()   # polars DataFrame: time, v(in), v(out)…

Repository layout

License

BSD-3-Clause — © 2026 André Leite; portions derived from SPICE3f5, © 1985–1991 The Regents of the University of California. See LICENSE.