All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

• Extended tp-flash algorithm to static numbers of components and enabled automatic differentiation for binary systems. #336
• Rewrote PhaseEquilibrium::pure_p to mirror pure_t and enabled automatic differentiation. #337
• Added boiling_temperature to the list of properties for parallel evaluations of gradients. #337
• Added the Composition trait to allow more flexibility in the creation of states and phase equilibria. #330

• Removed any assumptions about the total number of moles in a State or PhaseEquilibrium. Evaluating extensive properties now returns a Result. #330

• Removed the StateBuilder struct, because it is mostly obsolete with the addition of the Composition trait. #330

• Updated quantity dependency to 0.13 and removed the typenum dependency. #328

• Added py-feos tests to GitHub Actions and moved pyo3/extension-module feature to pyproject.toml. #334

• Fixed None transformation when binary parameters are provided to PyParameters to properly raise errors. #334
• Fixed the calculation of critical points and tp-flashes when one or more of the mixture components have zero composition. #331

• Fixed calculation of enthalpies of adsorption for mixtures. #329
• Updated to ndarray 0.17 and num-dual0.13 to fix a broken dependency resolution. #327
• Fixed calculation of parameter combination in entropy scaling for mixtures in viscosity_correlation, diffusion_correlation, thermal_conductivity_correlation. #323

• Fixed a wrong Jacobian entry in heteroazeotrope_t. (Thanks to @ImagineBaggins for reporting the issue) #320

• Integrated the functionalities of feos-ad. #289
  • In Rust: Full access to arbitrary derivatives of properties and phase equilibria with respect to model parameters. See, e.g., feos-campd for an application to molecular design.
  • In Python: Specialized functions for the parallel evaluation of relevant properties (vapor pressure, liquid density, bubble/dew point pressure) including the gradients with respect to model parameters for parameter estimations or the inclusion in backpropagation frameworks.
• Implement pure-component multiparameter equations of state from CoolProp. #301

• ⚠️ Changed the format of parameter files. The contents of the old model_record field are now flattened into the PureRecord/SegmentRecord. #233
• Generalized the implementation of association to allow for arbitrarily many association sites per molecule or group and full control over each interaction. #233 #290
• Reimplemented the Python interface to avoid the necessity of having multiple classes with the same name.
  • feos.eos.State and feos.dft.State (and analogous classes) are combined into feos.State. #274
  • All feos.<model>.PureRecord (and similar classes) are combined into feos.PureRecord. #271
• All Python classes are exported at the package root. #309
• Add initial density as optional argument to critical point algorithms. #300

• Updated quantity dependency to 0.12.
• Updated num-dual dependency to 0.12.
• Updated numpy, PyO3 and pythonize dependencies to 0.27.
• Updated nalgebra dependency to 0.34.

• Fixed the handling of association records in combination with induced association in PC-SAFT #264

• Updated quantity dependency to 0.10. #262
• Updated num-dual dependency to 0.11. #262
• Updated numpy and PyO3 dependencies to 0.23. #262

• Added SAFT-VR Mie equation of state. #237
• Added ePC-SAFT equation of state. #229

• Updated model implementations to account for the removal of trait objects for Helmholtz energy contributions and the de Broglie in feos-core. #226
• Changed Helmholtz energy functions in PcSaft contributions so that the temperature-dependent diameter is re-used across different contributions. #226
• Renamed structs in uvtheory module in accordance with names in other models (UV... to UVTheory...). #226
• Restructured uvtheory module: added modules for BH and WCA. #226
• Updated github action versions for CI/CD. #226
• Added codegen-units = 1 to release-lto profile. #226

• Removed VirialOrder from uvtheory module. Orders are now variants of the existing Perturbation enum. #226

• Updated quantity dependency to 0.8. #238
• Updated num-dual dependency to 0.9. #238
• Updated numpy and PyO3 dependencies to 0.21. #238

• Python only: Release the changes introduced in feos-core 0.6.1.

• Added EquationOfState.ideal_gas() to initialize an equation of state that only consists of an ideal gas contribution. #204
• Added PureRecord, SegmentRecord, Identifier, and IdentifierOption to feos.ideal_gas. #205
• Added implementation of the Joback ideal gas model that was previously part of feos-core. #204
• Added an implementation of the ideal gas heat capacity based on DIPPR equations. #204
• Added re-exports for the members of feos-core and feos-dft in the new modules feos::core and feos::dft. #212

• Split feos.ideal_gas into feos.joback and feos.dippr. #204

• Python only: Release the changes introduced in feos-core 0.5.1.

• Added IdealGasModel enum that collects all implementors of the IdealGas trait. #158
• Added feos.ideal_gas module in Python from which (currently) Joback and JobackParameters are available. #158
• Added binary association parameters to PC-SAFT. #167
• Added derive for EntropyScaling for SAFT-VRQ Mie to ResidualModel and adjusted parameter initialization. #179

• Changed the internal implementation of the association contribution to accomodate more general association schemes. #150
• To comply with the new association implementation, the default values of na and nb are now 0 rather than 1. Parameter files have been adapted accordingly. #150
• Added the possibility to specify a pure component correction parameter phi for the heterosegmented gc PC-SAFT equation of state. #157
• Adjusted all models' implementation of the Parameter trait which now requires Results in some methods. #161
• Renamed EosVariant to ResidualModel. #158
• Added methods to add an ideal gas contribution to an initialized equation of state object in Python. #158
• Moved molar_weight impls to Residual due to removal of MolarWeight trait. #177

• Updated quantity dependency to 0.7.
• Updated num-dual dependency to 0.8. #137
• Updated numpy and PyO3 dependencies to 0.20.

• Python only: Release the changes introduced in feos-core 0.4.2.

• Python only: Release the changes introduced in feos-core 0.4.1 and feos-dft 0.4.1.

• Replaced some slow array operations to make calculations with multiple associating molecules significantly faster. #129

• Fixed a regression introduced in #108 that lead to incorrect results for the 3B association scheme. #129

• Added SAFT-VRQ Mie equation of state and Helmholtz energy functional for first order Feynman-Hibbs corrected Mie fluids. #79
• Added estimator module to documentation. #86
• Added benchmarks for the evaluation of the Helmholtz energy and some properties of the State object for PC-SAFT. #89
• The Python class StateVec is exposed in both the feos.eos and feos.dft module. #113
• Added uv-B3-theory and additional optional argument virial_order to uvtheory constructor to enable uv-B3. #98

• Export EosVariant and FunctionalVariant directly in the crate root instead of their own modules. #62
• Changed constructors VaporPressure::new and DataSet.vapor_pressure (Python) to take a new optional argument critical_temperature. #86
• The limitations of the homo gc method for PC-SAFT are enforced more strictly. #88
• Removed generics for units in all structs and traits in favor of static SI units. #115

• Updated pyo3 and numpy dependencies to 0.18. #119
• Updated quantity dependency to 0.6. #119
• Updated num-dual dependency to 0.6. #119

• Fixed incorrect indexing that lead to panics in the polar contribution of gc-PC-SAFT. #104
• VaporPressure now returns an empty array instead of crashing. #124

• Major restructuring of the entire feos project. All individual models are reunited in the feos crate. feos-core and feos-dft still live as individual crates within the feos workspace.

• Fixed a bug due to which the default ideal gas contribution was used for every equation of state. #17

• Added gc-PC-SAFT equation of state and Helmholtz energy functional.
• Added PeTS equation of state and Helmholtz energy functional.
• Added UV-Theory equation of state for Mie fluids.

• Combined all equations of state into a single Python class EquationOfState and all Helmholtz energy functionals into the Python class HelmholtzEnergyFunctional. #11

• Updated quantity to 0.5.0.
• Updated feos-core to 0.2.0.
• Updated feos-dft to 0.2.0.
• Updated feos-pcsaft to 0.2.0.

• Added pyproject.toml. #8
• Fixed modules of SI classes to make them pickleable. #8

• Updated feos-core to 0.1.5.
• Updated feos-dft to 0.1.3.

• Initial release