PertDist

PertDist is a SciPy-style implementation of the Beta-PERT distribution.

Overview

The package exposes a PERT class with an API modeled after scipy.stats distributions. It supports scalar and array-based parameters and computes both distribution functions and descriptive statistics.

Installation

pip install pertdist

Python Version

• Python >= 3.11

Support

• Supported Python: 3.11+
• Primary package index: PyPI (pertdist)

Quick Start

from pert import PERT

dist = PERT(min_val=10, ml_val=190, max_val=200, lamb=4.0)

samples = dist.rvs(size=10_000, random_state=42)
mean = dist.mean
median = dist.median()
p90 = dist.ppf(0.90)

Implemented API

Constructor

• PERT(min_val, ml_val, max_val, lamb=4.0)

Properties / Attributes

• a, b, c, lamb
• alpha, beta
• mean, var, skew, kurt
• range (property)

Methods

• median()
• rvs(size=1, random_state=None) where size can be int or tuple[int, ...]
• pdf(x), logpdf(x)
• cdf(x), logcdf(x)
• sf(x), logsf(x)
• ppf(q), isf(q)
• interval(alpha)
• ci(z)
• stats()

Input Validation

The constructor enforces:

• lamb > 0
• strict ordering for each element: min_val < ml_val < max_val
• no adjacent equal values (min_val == ml_val or ml_val == max_val)

Testing

The project includes a pytest suite under tests/, including coverage for:

• initialization and validation
• distribution identities and boundary behavior
• sampling behavior and reproducibility
• vectorized inputs/outputs
• median, ci, and __repr__

Run tests with:

uv run pytest -q

Development Setup

Install development dependencies:

uv sync --all-extras --dev

Run lint and tests:

uv run ruff check .
uv run pytest -q

Roadmap

• Add additional SciPy-like analogues:
  • moment
  • entropy
  • fit
  • expect
  • std

Version History

See VersionHistory.md.

Contributing

• Community and core-developer contribution workflow is documented in CONTRIBUTING.md.
• Repository guardrails and policy details are defined in AGENTS.md.

Release Process (High-Level)

• Pull requests from release/* and hotfix/* into main run publish dry-run checks.
• Merged release/* / hotfix/* PRs to main trigger publish, tagging, release metadata, and post-release verification workflows.
• Recovery actions (including yank/unyank verification with runbook guidance) are run manually when needed.

Reporting Issues

• Bug reports and feature requests: GitHub Issues
• Security-sensitive concerns can be reported privately using GitHub repository security reporting.

Repository Policy

High-level development policy summary (full details in AGENTS.md):

• GitFlow is used: feature/* -> dev, release/*|hotfix/* -> main, with PR-based merges.
• Community contributions are welcome through feature/* -> dev pull requests; release/* and hotfix/* flows are core-developer managed.
• CI runs on PRs to dev and main; release dry-runs run on release/*/hotfix/* PRs to main; release publish runs after merge to main.
• Semantic Versioning is required (MAJOR.MINOR.PATCH) and versioning must be intentional.
• Some defaults are guidance (for example draft PR by default) and developer discretion is explicitly supported.
• uv.lock is developer-local and is not tracked in this repository.
• Functional library code is authored manually.
• AI tooling may assist with test authoring, documentation drafting/editing, GitHub Actions/workflow authoring and maintenance, and development guidance for planning/decision support.

For release notes and historical change context, see VersionHistory.md.

License

This project is licensed under the GNU GPL. See LICENSE.