pyaga8 0.1.18

Python package for calculating gas properties using the AGA8 equations GERG-2008 and DETAIL

pyaga8

Python bindings for the AGA8 GERG-2008 and DETAIL gas property equations, built on the Rust aga8 port of NIST's AGA8 code.

GitHub: https://github.com/equinor/pyaga8

Description

pyaga8 is a low-level Python interface to the AGA8 calculations. It exposes the underlying GERG-2008 and DETAIL state objects and methods directly, with Rust used for performance via pyo3.

Higher-level libraries such as pvtlib build on top of pyaga8 to provide workflows such as PT, PH, PS and rhoT calculations: https://github.com/equinor/pvtlib/blob/main/examples/gas_properties_from_aga8.py

Installation

pip install pyaga8

Minimal usage

import pyaga8

detail = pyaga8.Detail()
comp = pyaga8.Composition()
comp.methane = 0.9
comp.nitrogen = 0.1

detail.set_composition(comp)
detail.temperature = 400.0
detail.pressure = 50_000.0
detail.calc_density()

print(detail.d)

Error handling

Python-facing API methods raise normal Python exceptions when inputs or state are invalid; they do not intentionally panic the Python interpreter.

• set_composition(...) raises ValueError for invalid mixtures, for example an empty composition or a sum that is not close enough to 1.0.
• calc_density(...) / calc_density() raises ordinary Python exceptions based on the underlying failure, typically ValueError or RuntimeError.

pyaga8 is intentionally a lower-level library. Higher-level packages may choose to translate selected failures to NaN or other domain-specific behavior, but that translation is not part of pyaga8 itself.