Quantas is an open-source scientific toolkit for the quantitative analysis of solid-state properties. It was created to make demanding thermodynamic, elastic, seismic, and equation-of-state calculations easier to perform, inspect, reproduce, and reuse.
The code was redesigned from its original implementation (v0.9.1) as a reusable scientific library, where the same numerical implementation are used by the Python API and the command-line interface, and are intended to support other frontends without duplicating scientific logic.
Quantas 2 is currently in beta.
The main scientific workflows are extensively tested and are already being used for research calculations. The public API, file schemas, interfaces, and documentation may nevertheless receive further changes before the first stable 2.0 release.
A graphical user interface is in active development, and it will be provided as a separate package.
Quantas currently provides workflows for:
- harmonic and quasi-harmonic thermodynamics;
- Kieffer acoustic thermodynamics for suitable Gamma-point phonon calculations;
- second-order elasticity, mechanical stability, Voigt-Reuss-Hill averages, tensor rotations, and directional elastic properties;
- Christoffel analysis, phase and group velocities, polarization, anisotropy, and seismic surfaces;
- pressure-volume, energy-volume, volume-temperature, and coupled pressure-volume-temperature equations of state;
- quasi-static thermoelastic properties as functions of pressure and temperature, including geological-profile calculations.
The scientific workflows can be used from the command line or through the
public quantas.api Python interface.
Quantas also provides interfaces for reading and normalising data produced by electronic-structure and lattice-dynamics codes. Current support includes CRYSTAL and VASP workflows, with code-specific parsing kept separate from the scientific models.
Results from the main workflows are stored in self-describing HDF5 archives. These archives retain numerical results together with units, calculation options, provenance, warnings, diagnostics, and other information required to understand how a result was obtained.
Quantas currently supports Python 3.10 through 3.13. Python 3.14 is not yet supported because the complete scientific dependency stack has not been validated on that runtime.
The current Quantas 2 beta can be installed directly from the GitHub repository:
git clone https://github.com/gfulian/quantas.git
cd quantas
python -m pip install .Installation inside a dedicated virtual environment is recommended.
Optional plotting support can be installed with:
python -m pip install ".[plot]"For development work, install the complete development dependency set instead:
python -m pip install ".[dev]"Development builds and feature branches may change more frequently than the current master branch. Contributors should refer to CONTRIBUTING.md and DEVELOPMENT.md before starting new work.
The Quantas documentation contains installation guidance, scientific background, tutorials, command-line reference, Python API documentation, input-format descriptions, interoperability examples, and validation material.
Read the Quantas 2.0 beta documentation
Documentation for the historical Quantas 0.9.1 release remains available through the Read the Docs version selector.
Quantas is developed as scientific software. Changes to formulas, numerical methods, units, tensor conventions, or data interpretation are treated separately from presentation and structural cleanup.
Numerical changes are characterised with tests and, where possible, compared against analytical results, legacy behaviour, published data, or independent implementations before they are accepted.
Native calculations use double precision: real-valued scientific data are
stored as float64, and complex-valued data as complex128. Display precision
is handled separately and does not alter stored results.
Quantas is an academic, open-source software. If you use it in published work, please cite Quantas together with the scientific methods relevant to the calculation that was performed.
The canonical software citation is provided in CITATION.cff. Method-specific references are also included in the documentation and in the internal citation registry used by Quantas reports.
Contributions, bug reports, validation datasets, comparisons with independent implementations, and documentation improvements are welcome.
See CONTRIBUTING.md for contribution guidelines and DEVELOPMENT.md for the development and branch workflow.
Planned scientific and engineering work is summarised in ROADMAP.md.
Quantas is distributed under the BSD 3-Clause license. See LICENSE.