gaspatchio 0.5.2

Simple, fast and best served cold

Gaspatchio (Python)

The Python package for Gaspatchio — a high-performance actuarial modeling framework. You write models in Python that read like spreadsheet formulas, and a Rust + Polars engine runs them over millions of model points.

📖 Documentation, tutorials, and full API + CLI reference → gaspatchio.dev

Install

pip install gaspatchio        # or:  uv pip install gaspatchio

Then import gaspatchio_core. For a source/dev build, see Building from source.

Quick start

from gaspatchio_core import ActuarialFrame
from gaspatchio_core.assumptions import Table

# 1. Load assumption tables (registered + optimized by the Rust engine)
mortality = Table(
    name="mortality",
    source="data/mortality.parquet",
    dimensions={"age": "age", "gender": "sex"},
    value="rate",
)

# 2. Define the model — the formula IS the code
def projection(af: ActuarialFrame) -> ActuarialFrame:
    af.attained_age = af.dob.excel.yearfrac(af.val_date) + af.t      # Excel-compatible date maths
    af.qx = mortality.lookup(age=af.attained_age, gender=af.gender)  # vectorized lookup
    af.pols_if = af.pols_start * (1 - af.qx - af.lapse_rate)         # vectorized projection
    return af

# 3. Run (millions of model points supported)
af = ActuarialFrame(data="model_points.parquet")
result = projection(af).collect()

New here? The tutorials build from hello-world to a lifelib-reconciled model and on to scenarios.

CLI: gspio

Run models from the command line:

gspio run-model model.py model-points.parquet                  # run all policies
gspio run-single-policy model.py model-points.parquet 12345    # debug one policy (transposed output)
gspio run-model model.py data.parquet --mode optimize          # optimized execution
gspio --install-completion                                     # shell tab-completion

• --policy-id-column sets the policy-identifier column (default "Policy number").
• --mode {debug,optimize} plus display flags (--rows/-r, --first-n/-f, --last-n/-l, --start-at/-s) control execution and terminal output.

Full CLI reference, with every flag and the single-policy result transposition → gaspatchio.dev.

Building from source

The Rust extension is built with maturin. uv sync builds in debug mode (fast compiles); use --release for benchmarking/production:

uv sync                                                        # debug build, into the venv
maturin build --release -uv                                    # optimized build
RUSTFLAGS="-C target-cpu=native" maturin build --release -uv   # + native SIMD (AVX2/512)

target-cpu=native binaries only run on CPUs with the same or newer instruction sets — use them for local benchmarking, not for distributable packages or CI builds.

Testing

uv run pytest                                                  # tests + docstring-example validation
uv run python -m mypy.stubtest gaspatchio_core --allowlist stubtest-allowlist.txt --mypy-config-file mypy-stubtest.ini

Public-API docstrings carry examples validated against their output. The docstring/style tooling and contributor coding standards live in AGENTS.md.

Learn more

• 📖 Documentation — guides, tutorials, full API + CLI reference
• 🦀 Rust engine — the core that powers this package
• 🏠 Project overview