---
id: arviz-base
version: "1.3.0"
license: unclear
license_treatment: permissive
maintenance: active
---

# arviz-base — Base ArviZ features and converters.

License: permissive · Maintenance: active · Downloads: 607.4K/mo

## What it is and what it does

arviz-base is the foundation layer of the ArviZ ecosystem, a modular Python library for exploratory analysis of Bayesian models. This subpackage specifically handles data converters and base manipulation—the infrastructure for transforming posterior samples from different modeling tools into a common format and performing core data operations. It depends on numpy, xarray, typing-extensions, and lazy_loader to provide efficient storage and access to multidimensional inference data.

The package is designed as part of a larger ecosystem and targets researchers and practitioners working with Bayesian inference. It requires Python 3.12 or later and is actively maintained by the ArviZ community under NumFOCUS.

Use it for:

- Convert posterior samples from different Bayesian samplers into a standardized xarray-based format for downstream analysis
- Store and retrieve multidimensional inference data efficiently using xarray structures
- Build custom Bayesian analysis pipelines that need a common data layer across different modeling frameworks
- Integrate Bayesian model outputs into reproducible research workflows with standardized metadata

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Provides converters and base data manipulation functions for the ArviZ Bayesian analysis ecosystem, handling posterior data storage and transformation.

Yes, if you are working within the ArviZ ecosystem or need to standardize posterior data from multiple Bayesian modeling frameworks. The package is actively maintained, has no known vulnerabilities, and carries a permissive license. Verify first whether you need the full ecosystem or can use this subpackage independently.

## Install

pip install arviz-base
uv add arviz-base
poetry add arviz-base

## Installing arviz-base

Before you install: Low install friction with a pure-Python wheel and minimal dependencies. Active maintenance with a release 3 days old and recent commits suggest steady development.

License in practice: Licensed under Apache Software License (permissive), allowing commercial and private use without restriction.

Quickstart:

pip install arviz-base

import arviz_base
import numpy as np
import xarray as xr

Requires Python 3.12 or later

Verify before relying:

- Which specific Bayesian modeling frameworks are supported by the converters in this version
- Whether this subpackage can be used independently or requires other arviz packages for typical workflows
- Performance characteristics when handling large posterior datasets

## Package facts

- License: not declared (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 607.4K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

bayesian posterior data conversion, arviz converters, bayesian model data storage, posterior analysis tools, xarray bayesian data, inference data handling, mcmc output conversion, bayesian-inference, data-conversion, posterior-analysis

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