sedes 0.1.8

Parallel ngspice SPICE simulation from Python — LTspice-friendly, with built-in MOSFET LUT and gm/Id sizing

sedes

Parallel ngspice SPICE simulation from Python. LTspice-friendly, with built-in MOSFET LUT generation and gm/Id sizing.

• Cross-platform: prebuilt wheels for Linux, macOS, and Windows (x86_64, plus arm64 on macOS). Python 3.10+.
• No system ngspice required: libngspice is bundled inside the wheel.
• No GIL bottleneck: simulations run in parallel ngspice worker subprocesses, dispatched by an internal tokio runtime.
• Typed surface: ships py.typed and a hand-written .pyi so Pyright, Pylance, and mypy give you full autocomplete out of the box.

Install

pip install sedes

That's it — no Rust toolchain, no SPICE install, no DLL hunt.

Quickstart — run a netlist, sweep a value

import numpy as np
import sedes

# Build a circuit programmatically …
ckt = (sedes.Circuit("RC filter")
    .V("v1", "in", "0", "ac 1")
    .R("r1", "in", "out", "1k")
    .C("c1", "out", "0", "100n")
    .ac("dec", 100, 1, 1e6))

# … or load one exported from LTspice (View → SPICE Netlist):
# ckt = sedes.Circuit.from_file("filter.cir")

pool = sedes.SimulationPool(workers=8)

# One run
result = ckt.run(pool)
print(result.frequency.shape, result.vector("v(out)").shape)

# Multi-value sweep — Cartesian product, run in parallel.
results = sedes.sweep(ckt, pool, {"r1": ["1k", "2.2k", "10k"]})
for R, r in zip(["1k", "2.2k", "10k"], results):
    mag = r.mag("v(out)")
    f_3db = r.frequency[np.argmin(np.abs(mag - 1/np.sqrt(2)))]
    print(f"R={R:>4}  →  f_-3dB ≈ {f_3db:.0f} Hz")

A runnable version of this lives at examples/rc_sweep.py.

What's in the package

Import	Role
sedes.Circuit	Programmatic SPICE netlist builder. Load with Circuit.from_file(...), mutate with .set_value(), .replace(), .remove(), attach analyses with .op() / .tran() / .dc() / .ac() / .noise().
sedes.parse_file, parse_string	Standalone netlist parsers.
sedes.SimulationPool	Worker-pool dispatcher. pool.run_simulation(netlist, ["run"]), pool.run_simulations_batch(jobs), pool.generate_lut(cfg).
sedes.sweep	Cartesian-product parameter sweep over component values, returns typed result list.
sedes.LutConfig / sedes.Lut	MOSFET characterisation (Id, gm, gds, capacitances, ft) and gm/Id transistor sizing.
sedes.OpResult / TranResult / DCResult / ACResult / NoiseResult / …	Typed result wrappers with .plot() helpers.
sedes.PsfFile / sedes.NgpsfFile	Cadence PSF / PSFXL waveform readers (pure Rust, no libpsf).

Coming from LTspice?

Read docs/ltspice_migration.md for the export workflow and the syntax differences that matter (the big one: in ngspice, M is mega, m is milli — LTspice is more forgiving).

For sweep recipes (1-axis, 2-axis corner grids, MOSFET parameter sweeps) see docs/sweeps.md.

Supported platforms

OS	Architecture	Python
Linux	x86_64 (manylinux_2_28)	3.10–3.13
macOS	x86_64, aarch64	3.10–3.13
Windows	x86_64	3.10–3.13

Development

# Build once, populate the bundled libngspice into python/sedes/_libs:
bash ../.github/scripts/fetch_ngspice.sh macos python/sedes/_libs

# Build the extension and install it editable into a venv:
uv venv && uv pip install maturin numpy
uv run maturin develop --release
uv run python examples/rc_sweep.py

When you change the #[pyclass] / #[pyfunction] surface under src/python/ or src/psf/python.rs, also update python/sedes/sedes.pyi so IDE autocomplete remains accurate.

License

MIT — see LICENSE.