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.

• Added ReferenceSystem trait to handle conversion between SI units and reduced units. #257
• Readded Molarweight trait to avoid extra implementation requirements for some models. #258

• Removed si module after the compile-time units are incorporated into the quantity crate. #257

• 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 specific isochoric and isobaric heat capacities to the Python interface. #223)
• Added to_dict method for PyStateVec. #224
• Added State::henrys_law_constant to calculate Henry's law constants for arbitrary mixtures. #234

• Changed the interface for Helmholtz energy calculation in Residual and IdealGas which removes the need for the HelmholtzEnergy and HelmholtzEnergyDual traits and trait objects. #226
• Adjusted Python macros to account for the removal of trait objects. #226
• Changed deprecated remove method of IndexMap to shift_remove. #226
• Added contributions argument to State::chemical_potential_contributions and fixed the corresponding Python function. #228

• Removed HelmholtzEnergyDual, HelmholzEnergy, DeBroglieWavelengthDual and DeBroglieWavelength traits. #226

• Added comparison for pressures of both phases in PyPhaseDiagram.to_dict to make the method work with spinodal constructor. #224
• Enforce the total moles when providing State::new with molefracs that do not add up to 1. #227

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

• Improved convergence of tp_flash for certain edge cases. #219

• Added EquationOfState::ideal_gas to initialize an equation of state that only consists of an ideal gas contribution. #204
• Added NoBinaryModelRecord for models that do not use binary interaction parameters. #211

• Made members of JobackRecord public. #206

• Removed JobackParameters and JobackBinaryRecord. #204
• Moved the remaining implementation of Joback to feos. #204

• Aligned how binary segment records are treated in Rust and Python. #200

• Added new functions isenthalpic_compressibility, thermal_expansivity and grueneisen_parameter to State. #154
• Readded PhaseEquilibrium::new_npt to the public interface in Rust and Python. #164
• Added Components, Residual, IdealGas and DeBroglieWavelength traits to decouple ideal gas models from residual models. #158
• Added JobackParameters struct that implements Parameters including Python bindings. #158
• Added Parameter::from_model_records as a simpler interface to generate parameters. #169
• Added optional Phase argument for constructors of dynamic properties of DataSets. #174
• Added molar_weight method to Residual trait. #177
• Added molar versions for entropy, enthalpy, etc. for residual properties. #177
• Python only: Added SmartsRecord and ChemicalRecord.from_smiles that uses rdkit to calculate segments and bonds from a SMILES code. #191
• Python only: Added from_smiles and from_json_smiles to parameter objects that build parameters from SMILES codes using rdkit. #191

• Changed constructors of Parameter trait to return Results. #161
• Changed EquationOfState from a trait to a struct that is generic over Residual and IdealGas and implements all necessary traits to be used as equation of state including the ideal gas contribution. #158
• The Parameter trait no longer has an associated type IdealGas. #158
• Split properties of State into those that require the Residual trait (residual_properties.rs) and those that require both Residual + IdealGas (properties.rs). #158
• State creation routines are split into those that can be used with Residual and those that require Residual + IdealGas. #158
• Contributions enum no longer includes the ResidualNpt variant. ResidualNvt variant is renamed to Residual. #158
• Moved Verbosity and SolverOption from phase_equilibria module to lib.rs. #158
• Moved StateVec into own file and module. #158
• Ideal gas and residual Helmholtz energy models can now be separately implemented in Python via the PyIdealGas and PyResidual structs. #158
• Bubble and dew point iterations will not attempt a second iteration if no solution is found for the given initial pressure. #166
• Made the binary records in the constructions and getters of the Parameter trait optional. #169
• Changed the second argument of new_binary in Python from a BinaryRecord to the corresponding binary model record (analogous to the Rust implementation). #169
• Renamed c_v and c_p to isochoric_heat_capacity and isobaric_heat_capacity, respectively, and added prefixes for molar and specific properties. #177
• State.helmholtz_energy_contributions in Python now accepts optional Contributions. #177
• Changed StateVec Python getters for entropy and enthalpy to functions that accept optional Contributions. #177
• PhaseDiagram.to_dict in Python now accepts optional Contributions and includes mass specific properties. #177
• Replaced the run-time unit checks from the quantity crate with compile-time unit checks with custom implementations in the new feos_core.si module. #181
• Renamed the keyword argument search_option to identifier_option in parameter constructors. #196

• Removed EquationOfState trait. #158
• Removed ideal gas dependencies from PureRecord and SegmentRecord. #158
• Removed Python getter and setter functions and optional arguments for ideal gas records in macros. #158
• Removed MolarWeight trait. #177

• The vapor and liquid states in a bubble or dew point iteration are assigned correctly according to the inputs, rather than based on the mole density which can be incorrect for mixtures with large differences in molar weights. #166
• Parameter::from_multiple_json returns the correct parameters if a component occurs in multiple input files. #196

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

• Fixed a wrong reference state in the implementation of the Peng-Robinson equation of state. #151

• Fixed a bug that caused the bubble and dew point solvers to ignore the initial values for the opposing phase given by the user if no initial value for temperature/pressure was also given. #138

• Added PhaseDiagram::par_pure that uses rayon to calculate phase diagrams in parallel. #57
• Added StateVec::moles getter. #113
• Added public constructors PhaseDiagram::new and StateVec::new that allow the creation of the respective structs from a list of PhaseEquilibriums or States in Rust and Python. #113
• Added new variant EosError::Error which allows dispatching generic errors that are not covered by the existing variants. #98
• Added binary_records getter for parameter classes in Python. #104
• Added BinaryRecord::from_json and BinarySegmentRecord::from_json that read a list of records from a file. #104

• Added Sync and Send as supertraits to EquationOfState. #57
• Added Dual2_64 dual number to HelmholtzEnergy trait to facilitate efficient non-mixed second order derivatives. #94
• Renamed PartialDerivative::Second to PartialDerivative::SecondMixed. #94
• Added PartialDerivative::Second to enable non-mixed second order partial derivatives. #94
• Changed dp_dv_ and ds_dt_ to use Dual2_64 instead of HyperDual64. #94
• Added get_or_insert_with_d2_64 to Cache. #94
• The critical point algorithm now uses vector dual numbers to reduce the number of model evaluations and computation times. #96
• Renamed State::molar_volume to State::partial_molar_volume and State::ln_phi_pure to State::ln_phi_pure_liquid. #107
• Added a const generic parameter to PhaseDiagram that accounts for the number of phases analogously to PhaseEquilibrium. #113
• Removed generics for units in all structs and traits in favor of static SI units. #115

• Automatically generate all required data types to calculate higher order derivatives for equations of state implemented in Python. #114

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

• Parameter::from_segments only calculates binary interaction parameters for unlike molecules. #104

• Added State::spinodal that calculates both spinodal points for a given temperature and composition using the same objective function that is also used in the critical point calculation. #23
• Added PhaseDiagram::bubble_point_line, PhaseDiagram::dew_point_line, and PhaseDiagram::spinodal to calculate phase envelopes for mixtures with fixed compositions. #23

• Made binary parameters in from_records Python routine an Option. #35
• Added panic with message when parsing missing Identifiers variants. #35
• Generalized the initialization routines for pure component VLEs at given temperature to multicomponent systems. #23
• Increased the default number of maximum iterations for binary critical point calculations from 50 to 200. #48

• Removed the (internal) SpinodalPoint struct that was used within density iterations in favor of a simpler interface. #23

• Avoid panicking when calculating ResidualNpt properties of states with negative pressures. #42

• Added pure_records getter in the impl_parameter macro. #54
• Implemented Deref and IntoIterator for StateVec for additional vector functionalities of the StateVec. #55
• Added StateVec.__len__ and StateVec.__getitem__ to allow indexing and iterating over StateVecs in Python. #55
• Added SegmentCount trait that allows the construction of parameter sets from arbitrary chemical records. #56
• Added ParameterHetero trait to generically provide utility functions for parameter sets of heterosegmented Helmholtz energy models. #56

• Changed datatype for binary parameters in interfaces of the from_records and new_binary methods for parameters to take either numpy arrays of f64 or a list of BinaryRecord as input. #54
• Modified PhaseDiagram.to_dict function in Python to account for pure components and mixtures. #55
• Changed StateVec to a tuple struct. #55
• Made cas field of Identifier optional. #56
• Added type parameter to FromSegments and made its from_segments function fallible for more control over model limitations. #56
• Reverted ChemicalRecord back to a struct that only contains the structural information (and not segment and bond counts). #56
• Made IdentifierOption directly usable in Python using PyO3's new #[pyclass] for fieldless enums feature. #58

• Added conversions between ParameterError and EosError to improve the error messages in some cases. #40
• Added new struct StateVec, that gives easy access to properties of lists of states, e.g. in phase diagrams. #48
• Added ln_symmetric_activity_coefficient and ln_phi_pure to the list of state properties that can be calculated. #50

• Removed State from EntropyScaling trait and adjusted associated methods to use temperature, volume and moles instead of state. #36
• Replaced the outer loop iterations for the critical point of binary systems with dedicated algorithms. #34
• Renamed VLEOptions to SolverOptions. #38
• Renamed methods of StateBuilder and the parameters in the State constructor in python to molar_enthalpy, molar_entropy, and molar_internal_energy. #35
• Removed PyContributions and PyVerbosity in favor of a simpler implementation using PyO3's new #[pyclass] for fieldless enums feature. #41
• Renamed Contributions::Residual to Contributions::ResidualNvt and Contributions::ResidualP to Contributions::ResidualNpt. #43
• Renamed macro impl_vle_state! to impl_phase_equilibrium!. #48
• Removed _t and _p functions in favor of simpler interfaces. The kind of specification (temperature or pressure) is determined from the unit of the argument. #48
  • PhaseEquilibrium::pure_t, PhaseEquilibrium::pure_p -> PhaseEquilibrium::pure
  • PhaseEquilibrium::vle_pure_comps_t, PhaseEquilibrium::vle_pure_comps_p -> PhaseEquilibrium::vle_pure_comps
    The PhaseEquilibria returned by this function now have the same number of components as the (mixture) eos, that it is called with.
  • PhaseEquilibrium::bubble_point_tx, PhaseEquilibrium::bubble_point_px -> PhaseEquilibrium::bubble_point
  • PhaseEquilibrium::dew_point_tx, PhaseEquilibrium::dew_point_px -> PhaseEquilibrium::dew_point
  • PhaseEquilibrium::heteroazeotrope_t, PhaseEquilibrium::heteroazeotrope_p -> PhaseEquilibrium::heteroazeotrope
  • State::critical_point_binary_t, State::critical_point_binary_p -> State::crititcal_point_binary
• Combined PhaseDiagramPure and PhaseDiagramBinary into a single struct PhaseDiagram and renamed its constructors. Properties of the phase diagram are available from the vapor and liquid getters, that return StateVecs. #48
  • PhaseDiagramPure::new -> PhaseDiagram::pure
  • PhaseDiagramBinary::new_txy, PhaseDiagramBinary::new_pxy -> PhaseDiagram::binary_vle
  • PhaseDiagramBinary::new_txy_lle, PhaseDiagramBinary::new_pxy_lle -> PhaseDiagram::lle
  • PhaseDiagramHetero::new_txy, PhaseDiagramHetero::new_pxy -> PhaseDiagram::binary_vlle
    which still returns an instance of PhaseDiagramHetero
• Changed the internal implementation of the Peng-Robinson equation of state to use contributions like the more complex equations of state and removed the suggestion to overwrite the evaluate_residual function of EquationOfState. #51
• Moved the creation of the python module to the build_wheel auxilliary crate, so that only the relevant structs and macros are available for the dependents. #47

• Removed the utils module containing DataSet and Estimator in favor of a separate crate. #47

• Updated pyo3 and numpy dependencies to 0.16.
• Updated num-dual dependency to 0.5.
• Updated quantity dependency to 0.5.

• Fixed bug in predict of Estimator. #30

• Add pyproject.toml. #29

• Fix state constructor for T, p, V, x_i specification. #26

• Added method predict to Estimator. #27

• Changed method for vapor pressure in DataSet to vapor_pressure (was pressure of VLE liquid phase). #27

• Added the following properties to State: #21
  • dp_drho partial derivative of pressure w.r.t. density
  • d2p_drho2 second partial derivative of pressure w.r.t. density
  • isothermal_compressibility the isothermal compressibility
• Read a list of segment records directly from a JSON file. #22

• Changed ChemicalRecord to an enum that can hold either the full structural information of a molecule or only segment and bond counts and added an Identifier. #19
• Removed the chemical_record field from PureRecord and made model_record non-optional. #19

• Added from_multiple_json function to Parameter trait that is able to read parameters from separate JSON files. #15

• Updated pyo3 and numpy dependencies to 0.15.
• Updated quantity dependency to 0.4.
• Updated num-dual dependency to 0.4.
• Removed ndarray-linalg and ndarray-stats dependencies.
• Removed obsolete features for the selection of the BLAS/LAPACK library.

• Initial release