CHANGELOG.md

Changelog

All notable user-visible changes to this project are documented here.

[Unreleased]

Changed

• Python cea.Reactant now supports explicit enthalpy_units for custom reactant enthalpy input (J/kg, kJ/kg, cal/kg, kcal/kg, J/mol, kJ/mol, cal/mol, kcal/mol; /mol and /mole spellings accepted).
• Backward-compatible behavior is preserved when Reactant.enthalpy is provided without enthalpy_units: the legacy default (J/kg) is still used, but this now emits a FutureWarning directing users to pass enthalpy_units explicitly.
• Weight-based enthalpy units (*/kg) now require Reactant.molecular_weight for conversion, while molar units (*/mol) do not require molecular weight for enthalpy interpretation.
• Python docs and examples were updated to pass explicit enthalpy_units for custom reactants (including RP-1311 Example 5) instead of relying on implicit defaults.
• Compatibility notice: a future minor version increment will require enthalpy_units whenever Reactant.enthalpy is defined. Code that currently relies on implicit enthalpy units may break until updated.
• Smooth-truncation derivative assembly in the equilibrium solver now uses an effective Jacobian/chain-rule formulation across TP/HP/SP/TV/UV/SV solves so reported sensitivities track the smoothed species-activity model more consistently near truncation thresholds.

Fixed

• Smooth-truncation total derivatives for reported gas species and derived thermodynamic outputs were aligned with the final reported-species mapping, improving behavior for trace-species sensitivities near truncation cutoffs.
• Corrected user-facing viscosity unit labels in the equilibrium core comments and Python bindings to report millipoise consistently.

Added

• Added Python regression coverage for Reactant enthalpy-unit handling, including omitted-units warning behavior, explicit molar/weight units, molecular-weight requirements for weight units, and accepted unit spellings.
• Added pfunit regression coverage for smooth-truncation derivative chain-rule behavior, targeted finite-difference agreement across TP/HP/SP/TV/UV/SV constraints, and reported-entropy consistency checks.

[3.1.2] - 2026-03-23

Changed

• Legacy CLI .out files now echo each problem’s original input block before the corresponding equilibrium, rocket, shock, or detonation output section.
• Frozen rocket failure handling was aligned with the established partial-output behavior: successful upstream stations are retained, output truncates at the last valid station, and the existing warning text is emitted after the partial report.
• Frozen rocket stop checks now use the active thermo-fit interval for condensed species plus the existing lower-temperature frozen-fit guard, and frozen retained points now populate transport properties before output.

Fixed

• Non-converging frozen rocket cases no longer produce empty output, overrun into invalid exit columns, or crash while writing partial results.
• Difficult frozen rocket chamber solves can now retain a usable reduced-component state after repeated singular matrices, restoring partial output for reproduced failure cases.

Added

[3.1.1] - 2026-03-18

Changed

• Python Mixture input validation now accepts str and cea.Reactant entries (including mixed lists) and no longer accepts raw bytes species names (#53).
• Added SI-focused custom-reactant handling at the Python API layer: Reactant.temperature is specified in K and Reactant.enthalpy in J/kg (converted internally for core input) (#53).
• Legacy input parsing now supports repeated outp dataset keywords (including multiline forms) by merging successive outp entries during dataset assembly (#52).
• FAC rocket chamber-closure iteration logic in RocketSolver_solve_fac was updated toward CEA2 parity: Option-1 pressure correction direction now follows legacy semantics, the Option-1 convergence check is normalized to assigned injector pressure, the fixed 4-pass outer loop was replaced with tolerance-driven iteration plus a bounded safety guard, and FAC combustor-end reseeding now refreshes from the current infinity state each chamber iteration (#54).
• Legacy SHCK branch sequencing and output selection were reworked toward CEA2 parity: explicit incident requests now report only the requested incident branch (with reflected state attached when requested), while reflected-only requests continue exploring the mixed equilibrium/frozen permutations.
• Shock reports now include incident/reflected transport tables (Visc, Cp, Conductivity, Prandtl Number) when outp tran is enabled and transport data are available.
• Python test/main-interface helper workflows no longer require pandas; CSV result output is now written with the standard library and the installation guidance/environment were updated accordingly.

Fixed

• Legacy CLI equilibrium/rocket/shock workflows now propagate include_ions into generated product mixtures so ionized products are retained when requested (#52).
• Reflected-shock velocity outputs were corrected for reflected equilibrium/frozen workflows: the legacy CEA2 u5/u5+v2 relations effectively used rho5/rho2 where the reflected-shock mass balance requires rho5/rho2 - 1, so the old equations underpredicted reflected velocities and did not satisfy the reflected conservation equations. CEA now reports conservation-consistent u5, u5+v2, sonic speed, reflected ratios, and reflected-frozen header thermodynamic values.
• Shock failure handling now stops at the last valid state instead of emitting partially invalid reflected results; failed downstream shock states are explicitly zeroed for consistent output.
• Shock transport-property calculations now preserve and restore stable transport seeds across singular-recovery paths, fixing incorrect or missing transport values in difficult reflected-shock cases.

Added

• Added C and Python support for custom reactant data (including species not present in thermo.lib) in parity with the main interface workflow used by RP-1311 Example 5 (#53).
• Added new C-API constructors for generating product mixtures from input-reactant payloads: cea_mixture_create_products_from_input_reactants and cea_mixture_create_products_from_input_reactants_w_ions (#53).
• Added a shared bindc parser path for cea_reactant_input -> ReactantInput conversion to reduce duplicated C-binding logic (#53).
• Added Python cea.Reactant and mixed-input Mixture(...) support in the Cython binding (#53).
• Added shock regression coverage for transport output population across equilibrium/frozen branches and for singular-recovery reflected-shock cases.
• Added a Python pytest reflected-shock conservation check that verifies incident/reflected mass, momentum, and energy balances and confirms the corrected u5+v2 relation.

[3.1.0] - 2026-03-02

Changed

• Added equilibrium total-derivative capabilities across core solver paths (TP/HP/TV/UV/SP/SV), including chain-rule state/property derivatives and related thermo/property plumbing updates (#50).
• Exposed derivative workflows in the C and Python interfaces, including derivative object lifecycle, analytic-vs-finite-difference result accessors, and central finite-difference verification options (#50).
• Introduced optional smooth species truncation controls (with configurable width) through solver options in Fortran/C/Python interfaces to improve derivative behavior near composition cutoffs (#50).
• C binding headers and the RP-1311 C sample were updated to resolve compiler warnings (#49).

Fixed

Added

• Added extensive regression coverage for derivative correctness and stability, including new pfunit derivative suites and Python tests for smooth-truncation behavior and sample execution (#50).
• Added derivative-focused Python examples and documentation (including SP and multi-state derivative sample scripts and run helpers) (#50).

[3.0.4] - 2026-02-27

Changed

• Command-line input parsing now accepts explicit .inp filenames (#44).
• Python RP-1311 sample scripts were moved into source/bind/python/cea/samples/rp1311/ for clearer organization (#47).
• Expanded reac input compatibility with CEA2-style forms, including case-insensitive keywords, exploded formulas with implicit coefficients, den density aliases, molecular-weight aliases, and stricter mixed mole/weight basis validation (#48).
• User-specified reactant enthalpy input is now applied as a runtime override for reactant thermo initialization (including database species) (#48).

Fixed

• Fixed a crashing output case and restored missing output values (#45).
• Reusing EqSolution across solve calls now resets transient iteration state and recovers from prior non-converged attempts using the last stable warm-start seed, preventing reuse-related non-convergence regressions (#47).

Added

• Added missing Python test dependencies to improve out-of-the-box test runs (#41).
• Added Fortran and Python regression tests covering EqSolution reuse and detonation/equilibrium convergence behavior (#47).
• Added reac parser regression tests for custom species inputs, molecular-weight aliases, density aliases/default units, case-insensitive tokens, and implicit formula coefficients (#48).

[3.0.3] - 2026-02-20

Changed

• Hardened PyPI publishing CI with OIDC preflight checks and manual workflow_dispatch target selection (testpypi/pypi); installation docs now lead with python -m pip install cea and mention GitHub Releases binary assets. (#39, #40).

Fixed

Added

[3.0.2] – 2026-02-20

Added

• Initial Microsoft Visual C++ (MSVC) support in the C bindings/build pipeline (#29).

Changed

• RocketSolver_solve now treats pi_p as optional for better API compatibility and easier caller usage (#36).

Fixed

• Corrected detonation-wave upstream enthalpy calculations and upstream molecular weight handling in the legacy interface (#33).
• Resolved failing transport-property test cases to restore expected regression behavior (#37).

[3.0.1] – 2026-02-11

Added

• Python bindings and examples/tests for the CEA interface (Feat/icx python binding, #23).
• rp1311_examples.inp and updated C sample output including M (1/n) (#24).
• Windows 11 Intel oneAPI walkthrough documentation.
• GitHub issue and pull request templates for contribution workflow.
• A local findloc implementation in extern/fbasics for legacy compiler support.

Changed

• Core equilibrium/rocket/shock solver iteration logic and convergence rules were refined, including area-ratio loops, throat updates, and frozen-flow gating/criteria.
• Condensed-species handling was tightened across initialization and iteration paths (ordering, active-element indexing, phase checks, and first-iteration thermo evaluation).
• Build and CI configuration was expanded and hardened (compiler flags/presets, broader build/test coverage, and workflow updates).
• Precompiled thermo/transport database blobs were removed from the repository/package test assets in favor of build-time generation.
• Documentation, contribution guidance, and sample scripts were updated for current workflows.

Fixed

• Singular-matrix recovery paths in equilibrium condensed-species solves (including element-row singularities and related index handling).
• Multiple convergence and initialization edge cases in shock/frozen/throat calculations (including denominator guards and corrected initial values).
• Several compiler-compatibility issues (including Intel ifx workarounds and initialization safety fixes in mixture/transport paths).
• Intermittent CTest instability from an extraneous C format specifier.
• Sample/README correctness issues (including reversed example arguments and text typos).

[3.0.0] – 2025-12-31

• Initial public release.