Peritheos

Peritheos is a focused Python library for pressure-volume and pressure-volume-temperature equations of state for solid materials. It provides forward evaluation, pressure-volume inversion, thermoelastic properties, and least-squares parameter fitting.

The documentation is organized around scientific workflows:

• Getting started introduces isothermal and thermal use.
• Material catalog covers executable lookup and typed discovery across all 209 materials and 574 literature records.
• EOS models lists parameters, assumptions, and useful limits.
• Equation reference defines the implemented isothermal and thermal equations and their coefficients.
• Thermoelastic properties defines every derived property and its units.
• Fitting data covers P-V and P-V-T regression with uncertainty.
• Executable tutorial notebooks provide complete workflows:
• Pressure calibration quickstart calculates, inverts, validates, and propagates uncertainty for a hot MgO pressure marker.
• Normalize mixed pressure scales finds a common target for Au-, Pt-, and ruby-referenced sample EOSs, then executes and audits each transformation route.
• Comparing room-temperature EOS contrasts fit diagnostics, parameter correlation, and extrapolation for four common equations.
• Birch-Murnaghan f-F diagnostic compares BM2 and BM3 fits to bundled room-temperature coesite data and constructs the conventional normalized-stress plot explicitly.
• Comparing gold pressure scales evaluates named literature records only on their common validity domains.
• Thermal EOS state surfaces uses broadcasting, inversion, and thermoelastic properties on a P-V-T grid.
• Fit to prediction uncertainty carries fitted covariance into correlated linear and Monte Carlo intervals.
• Exploring the material library searches the complete bundled catalog and constructs executable records.
• EOSMAT round-trip validates, writes, reloads, and safely handles provisional material records.
• DAC temperature sensitivity studies the two-volume thermal-confinement boundary condition.
• Aragonite P-V-T fitting reproduces a published 64-point staged thermal analysis.
• Calculation uncertainty propagates fitted or published parameter errors into EOS predictions.
• Dioptas and .eosmat defines the shared material ownership and bundled 210-material-document/574-record EOS library.
• .eosmat schema reference documents every exchange field, model discriminator, default, unit, and compatibility rule.
• Advanced DAC analysis documents the optional two-volume thermal-pressure boundary-condition model.
• Units and reference states explains the deliberately strict thermal volume convention.
• Validation describes the numerical and literature checks.
• Paper investigation ledger gives the final disposition of every primary paper reviewed, including unreproduced, unavailable-data, withheld, and deferred cases.
• Primary EOS refit validation reports a fit attempt for every bundled material record and lists all coefficient-parity failures.
• API reference is a compact import and method reference.
• API stability defines the compatibility contract.

Scope

Peritheos models homogeneous solid phases on a chosen reference isotherm. It does not currently calculate phase equilibria, solid solutions, shear moduli, or fluid fugacities. Thermodynamic free energies exposed by the Mie-Gruneisen models are vibrational contributions; they are not absolute formation energies.

Building these docs

python -m pip install -r docs/requirements.txt
mkdocs serve

The site executes its bundled fitting notebook against the local CSV dataset; it does not download scientific data during the build:

mkdocs build --strict

Citation

Cite Peritheos using the repository's CITATION.cff metadata and cite the original source for each EOS used. See References for the model-specific literature.