Cantera

The Cantera development team is pleased to announce the availability of Cantera 3.1.0b1. There have been over [1400 commits](https://github.com/Cantera/cantera/wiki/Cantera-3.1.0-Changelog) to Cantera since the last version, 3.0.0, which was released in August 2023. We have closed or merged [112 pull requests](https://github.com/Cantera/cantera/pulls?q=is%3Apr+merged%3A2023-08-23..2024-11-10+is%3Aclosed) and closed [75 issues](https://github.com/Cantera/cantera/issues?q=is%3Aissue+closed%3A2023-08-23..2024-11-10+is%3Aclosed) and [23 enhancement proposals](https://github.com/Cantera/enhancements/issues?q=is:issue+closed:2023-08-23..2024-11-10+is:closed). Instructions for installing Cantera 3.1 are available on the [Cantera website](https://cantera.org/dev/install/index.html).

Highlights

- Render [examples](https://cantera.org/dev/examples/python/index.html) using Sphinx-gallery ([#1621](https://github.com/Cantera/cantera/pull/1621), [#1681](https://github.com/Cantera/cantera/pull/1681), [#1724](https://github.com/Cantera/cantera/pull/1724), [E#88](https://github.com/Cantera/enhancements/issues/88))
- Added visualizations of reactor networks; see [mix1.py](https://cantera.org/dev/examples/python/reactors/mix1.html) and [reactor2.py](https://cantera.org/dev/examples/python/reactors/reactor2.html) ([E#180](https://github.com/Cantera/enhancements/issues/180), [#1624](https://github.com/Cantera/cantera/pull/1624), [#1714](https://github.com/Cantera/cantera/pull/1714), [#1792](https://github.com/Cantera/cantera/pull/1792), [E#212](https://github.com/Cantera/enhancements/issues/212))
- Added ability to solve diffusion flames on the unstable branch using control of the temperature at two interior points; see [diffusion_flame_continuation.py](https://cantera.org/dev/examples/python/onedim/diffusion_flame_continuation.html) ([#1622](https://github.com/Cantera/cantera/pull/1622), [#1779](https://github.com/Cantera/cantera/pull/1779))
- Added the [linear-Burke](https://cantera.org/dev/reference/kinetics/rate-constants.html#sec-linear-burke) reaction rate parameterization which models pressure-dependent reactions with collider-specific behavior; see [shock_tube.py](https://cantera.org/dev/examples/python/kinetics/shock_tube.html), [jet_stirred_reactor.py](https://cantera.org/dev/examples/python/kinetics/jet_stirred_reactor.html), and [flame_speed.py](https://cantera.org/dev/examples/python/onedim/flame_speed.html) ([E#157](https://github.com/Cantera/enhancements/issues/157), [#1710](https://github.com/Cantera/cantera/pull/1710), [#1801](https://github.com/Cantera/cantera/pull/1801))
- Major expansion of documentation for [contributing to Cantera](https://cantera.org/dev/develop/index.html) and [understanding its internal workings](https://cantera.org/dev/reference/onedim/index.html) ([E#25](https://github.com/Cantera/enhancements/issues/25), [#1700](https://github.com/Cantera/cantera/pull/1700), [#1757](https://github.com/Cantera/cantera/pull/1757), [#1786](https://github.com/Cantera/cantera/pull/1786))
- Update website structure to keep all version-specific documentation together and simplify URLs ([E145](https://github.com/Cantera/enhancements/issues/145), [E#146](https://github.com/Cantera/enhancements/issues/146), [#1631](https://github.com/Cantera/cantera/pull/1631), [#1638](https://github.com/Cantera/cantera/pull/1638), [#1647](https://github.com/Cantera/cantera/pull/1647), [#1657](https://github.com/Cantera/cantera/pull/1657), [#1657](https://github.com/Cantera/cantera/pull/1657), [#1737](https://github.com/Cantera/cantera/pull/1737), [#1766](https://github.com/Cantera/cantera/pull/1766), [#1790](https://github.com/Cantera/cantera/pull/1790))
- Significant refactoring of the clib interface, which is now declared experimental and subject to API changes without receiving deprecation warnings. ([E211](https://github.com/Cantera/enhancements/issues/211), [E#199](https://github.com/Cantera/enhancements/issues/199), [#1741](https://github.com/Cantera/cantera/pull/1741), [#1752](https://github.com/Cantera/cantera/pull/1752), [#1760](https://github.com/Cantera/cantera/pull/1760), [#1769](https://github.com/Cantera/cantera/pull/1769), [#1773](https://github.com/Cantera/cantera/pull/1773), [#1780](https://github.com/Cantera/cantera/pull/1780))

New features

- Add electron collision reactions (C++ class [ElectronCollisionPlasmaRate](https://cantera.org/dev/cxx/d9/ddb/classCantera_1_1ElectronCollisionPlasmaRate.html)) based on cross section data from the LXCat database; see [plasma.py](https://cantera.org/dev/examples/python/reactors/plasma.html) ([#1262](https://github.com/Cantera/cantera/pull/1262))
- Added an example demonstrating a 1D packed-bed reactor; see [1D_packed_bed.py](https://cantera.org/dev/examples/python/reactors/1D_packed_bed.html) ([E#43](https://github.com/Cantera/enhancements/issues/43))
- Added option to compute diffusive fluxes using mass fraction gradients in the 1D solver ([E195](https://github.com/Cantera/enhancements/issues/195), [#1668](https://github.com/Cantera/cantera/pull/1668))
- Expose Peng-Robinson EoS parameters to Python interface ([1664](https://github.com/Cantera/cantera/pull/1664))
- Created a new repository to clearly identify example input data and allow use of larger, more detailed mechanisms ([E22](https://github.com/Cantera/enhancements/issues/22), [#1689](https://github.com/Cantera/cantera/pull/1689))
- Add HDF5 support to PyPI packages ([E205](https://github.com/Cantera/enhancements/issues/205), ([#1727](https://github.com/Cantera/cantera/pull/1727))
- Add stack trace option to CanteraError for enhanced debugging ([1730](https://github.com/Cantera/cantera/pull/1730))
- Enable cross compiling support without patches to simplify some package builds ([E210](https://github.com/Cantera/enhancements/issues/210), [#1749](https://github.com/Cantera/cantera/pull/1749))
- Add support for Python 3.12 ([1604](https://github.com/Cantera/cantera/pull/1604), [#1648](https://github.com/Cantera/cantera/pull/1648), [#1716](https://github.com/Cantera/cantera/pull/1716))
- Add compatibility with SUNDIALS 7.0 ([1672](https://github.com/Cantera/cantera/pull/1672))
- Add compatibility with NumPy 2.0 ([1706](https://github.com/Cantera/cantera/pull/1706), [#1713](https://github.com/Cantera/cantera/pull/1713))
- Support compilation in C++20 mode ([1739](https://github.com/Cantera/cantera/pull/1739))
- Automatically adjust temperature bounds for low-temperature flames ([1684](https://github.com/Cantera/cantera/issues/1684), [#1705](https://github.com/Cantera/cantera/pull/1705))

Changes to existing capabilities
- Refactored implementation of 1D flame governing equations ([1595](https://github.com/Cantera/cantera/pull/1595), [#1619](https://github.com/Cantera/cantera/pull/1619))
- Improvements to 1D solver logging ([1660](https://github.com/Cantera/cantera/pull/1660), [#1759](https://github.com/Cantera/cantera/pull/1759))
- Significant improvements to error messages reported when converting mechanisms using ck2yaml ([1669](https://github.com/Cantera/cantera/pull/1669), [#1736](https://github.com/Cantera/cantera/pull/1736))
- Improved handling of edge cases involving third body colliders and “duplicate” reactions ([1696](https://github.com/Cantera/cantera/pull/1696))
- Improve distinction between selecting none and default transport models ([1680](https://github.com/Cantera/cantera/issues/1680), [#1705](https://github.com/Cantera/cantera/pull/1705))
- Improve error message for flames initialized with bad boundary conditions ([1694](https://github.com/Cantera/cantera/issues/1694), [#1705](https://github.com/Cantera/cantera/pull/1705))
- Disallow redundant flame grid specification ([1693](https://github.com/Cantera/cantera/issues/1693), [#1705](https://github.com/Cantera/cantera/pull/1705))
- Simplify YAML input for extensible interface reactions ([1709](https://github.com/Cantera/cantera/pull/1709))
- Improve consistency of Func1 API between Matlab and Python interfaces ([1758](https://github.com/Cantera/cantera/pull/1758), [#1798](https://github.com/Cantera/cantera/pull/1798))
- Use Solution objects to store reactor contents ([1663](https://github.com/Cantera/cantera/pull/1663), [#1685](https://github.com/Cantera/cantera/pull/1685))
- Move locks that prevent adding species to ThermoPhase objects that are in use from Python to C++ ([1686](https://github.com/Cantera/cantera/pull/1686))
- Use Jinja templates in C sourcegen ([1785](https://github.com/Cantera/cantera/pull/1785))
- Update ck2yaml to use argparse ([1616](https://github.com/Cantera/cantera/pull/1616))
- Make names generated for reactor network objects reproducible ([1765](https://github.com/Cantera/cantera/pull/1765))
- Make generated sources and error messages deterministic ([1804](https://github.com/Cantera/cantera/pull/1804))
- Remove features deprecated in Cantera 3.0. ([1605](https://github.com/Cantera/cantera/pull/1605))
- Remove legacy Matlab toolbox ([E196](https://github.com/Cantera/enhancements/issues/196), [#1670](https://github.com/Cantera/cantera/pull/1670), [#1688](https://github.com/Cantera/cantera/pull/1688))
- Remove python_minimal interface ([E208](https://github.com/Cantera/enhancements/issues/208), [#1745](https://github.com/Cantera/cantera/pull/1745))
- Expanded automated CI testing and other CI maintenance ([1608](https://github.com/Cantera/cantera/pull/1608), [#1612](https://github.com/Cantera/cantera/pull/1612), [#1630](https://github.com/Cantera/cantera/pull/1630), [#1652](https://github.com/Cantera/cantera/pull/1652), [#1662](https://github.com/Cantera/cantera/pull/1662), [#1671](https://github.com/Cantera/cantera/pull/1671), [#1677](https://github.com/Cantera/cantera/pull/1677), [#1703](https://github.com/Cantera/cantera/pull/1703), [#1738](https://github.com/Cantera/cantera/pull/1738), [#1752](https://github.com/Cantera/cantera/pull/1752))
- Various documentation updates ([1618](https://github.com/Cantera/cantera/pull/1618), [#1659](https://github.com/Cantera/cantera/pull/1659), [#1702](https://github.com/Cantera/cantera/pull/1702), [#1795](https://github.com/Cantera/cantera/pull/1795), [#1803](https://github.com/Cantera/cantera/pull/1803))
- Various build system updates ([1723](https://github.com/Cantera/cantera/pull/1723), [#1746](https://github.com/Cantera/cantera/pull/1746), [#1750](https://github.com/Cantera/cantera/pull/1750), [#1755](https://github.com/Cantera/cantera/pull/1755), [#1768](https://github.com/Cantera/cantera/pull/1768), [#1782](https://github.com/Cantera/cantera/pull/1782), [#1791](https://github.com/Cantera/cantera/pull/1791), [E#209](https://github.com/Cantera/enhancements/issues/209))
- Fix some compiler warnings ([1729](https://github.com/Cantera/cantera/pull/1729))
- Maintenance of the sdist / PyPI packages ([1625](https://github.com/Cantera/cantera/pull/1625), [#1708](https://github.com/Cantera/cantera/pull/1708), [#1796](https://github.com/Cantera/cantera/pull/1796))
- Address some website accessibility issues ([E41](https://github.com/Cantera/enhancements/issues/41), [#1753](https://github.com/Cantera/cantera/pull/1753))
- Complete transition of the Python test suite to use pytest instead of the unittest module ([1793](https://github.com/Cantera/cantera/pull/1793))
- Update generated CMakeLists.txt files ([1742](https://github.com/Cantera/cantera/issues/1742), [#1744](https://github.com/Cantera/cantera/pull/1744))

Bugs fixed
- Fix missing porosity in PorousMediaBurner.py ([1617](https://github.com/Cantera/cantera/pull/1617))
- Fix various issues in the experimental Matlab toolbox and add missing functions ([1586](https://github.com/Cantera/cantera/pull/1586), [#1701](https://github.com/Cantera/cantera/pull/1701), [#1761](https://github.com/Cantera/cantera/pull/1761))
- Fix converting surface mechanisms that use a separate thermo data file ([1637](https://github.com/Cantera/cantera/pull/1637))
- Use midpoint properties for diffusion fluxes in 1D solver ([E187](https://github.com/Cantera/enhancements/issues/187), [#1626](https://github.com/Cantera/cantera/pull/1626))
- Fix access to Solution report when using with_units ([1650](https://github.com/Cantera/cantera/pull/1650))
- Prevent segfaults from accessing partially-constructed reactor objects ([1661](https://github.com/Cantera/cantera/pull/1661))
- Fix setting diffusion flame initial guess from known data ([1674](https://github.com/Cantera/cantera/issues/1674), [#1705](https://github.com/Cantera/cantera/pull/1705))
- Fix issues with slicing SolutionArray ([1725](https://github.com/Cantera/cantera/pull/1725), [#1726](https://github.com/Cantera/cantera/pull/1726))
- Fix yaml2ck handling of multiline note fields and phases with no reactions ([1733](https://github.com/Cantera/cantera/pull/1733))
- Fix a memory leak when reinitializing a reactor using the GMRES sparse solver ([1732](https://github.com/Cantera/cantera/pull/1732))
- Fix YAML serialization of changes to reaction/species flags with default values that are normally omitted ([1629](https://github.com/Cantera/cantera/issues/1629), [#1740](https://github.com/Cantera/cantera/pull/1740))
- Fix serialization of note fields that can be erroneously interpreted as integers ([1610](https://github.com/Cantera/cantera/issues/1610), [#1740](https://github.com/Cantera/cantera/pull/1740))
- Fix YAML serialization of multiline strings ([1695](https://github.com/Cantera/cantera/issues/1695), [#1740](https://github.com/Cantera/cantera/pull/1740))
- Fix garbage collection-related segfault with CustomRate ([1763](https://github.com/Cantera/cantera/pull/1763))
- Fix compatibility with SUNDIALS 6.0 and 6.1 ([1774](https://github.com/Cantera/cantera/pull/1774))
- Fix overwriting and ordering of components when outputting SolutionArray to YAML ([1775](https://github.com/Cantera/cantera/pull/1775), [#1781](https://github.com/Cantera/cantera/pull/1781))

The Cantera development team is pleased to announce the availability of Cantera 3.0.0. There have been over [1400 commits](https://github.com/Cantera/cantera/wiki/Cantera-3.0.0-Changelog) to Cantera since the last version, 2.6.0, which was released in May 2022. We have closed or merged [192 pull requests](https://github.com/Cantera/cantera/pulls?q=is%3Apr+merged%3A2022-05-01..2023-08-22+is%3Aclosed) and closed [111 issues](https://github.com/Cantera/cantera/issues?q=is%3Aissue+closed%3A2022-05-01..2023-08-22+is%3Aclosed). Instructions for installing Cantera 3.0 are available on the [Cantera website](https://cantera.org/install/index.html).

Highlights

- Major performance enhancements for reactor network calculations with large kinetic mechanisms. This comes from a new formulation for the reactor governing equations using species moles (rather than mass fractions) used together with a sparse, iterative solver in the ODE integrator that makes use of a semi-analytical Jacobian. ([`preconditioned_integration.py`](https://cantera.org/examples/python/reactors/preconditioned_integration.py.html), [#1010](https://github.com/Cantera/cantera/pull/1010), [#1344](https://github.com/Cantera/cantera/pull/1344), [#1363](https://github.com/Cantera/cantera/pull/1363), [#1377](https://github.com/Cantera/cantera/pull/1377), [#1411](https://github.com/Cantera/cantera/pull/1411))
- Introduce `ExtensibleRate` Python class that can be used to implement new reaction rate parameterizations in Python, with parameters defined in YAML input files. These rate types can be used even when the main user application is not written in Python. ([class `ExtensibleRate`](https://cantera.org/documentation/docs-3.0/sphinx/html/cython/kinetics.html#extensiblerate), [`custom_reactions.py`](https://cantera.org/examples/python/kinetics/custom_reactions.py.html), [#1382](https://github.com/Cantera/cantera/pull/1382), [#1417](https://github.com/Cantera/cantera/pull/1417), [#1456](https://github.com/Cantera/cantera/pull/1456), [#1478](https://github.com/Cantera/cantera/pull/1478), [#1494](https://github.com/Cantera/cantera/pull/1494), [#1499](https://github.com/Cantera/cantera/pull/1499))
- Introduce a C++ `SolutionArray` class, which is now used as the backend for the Python `SolutionArray` class ([E137](https://github.com/Cantera/enhancements/issues/137), [#1385](https://github.com/Cantera/cantera/pull/1385), [#1426](https://github.com/Cantera/cantera/pull/1426), [#1458](https://github.com/Cantera/cantera/pull/1458), [#1462](https://github.com/Cantera/cantera/pull/1462), [#1464](https://github.com/Cantera/cantera/pull/1464), [#1508](https://github.com/Cantera/cantera/pull/1508), [#1520](https://github.com/Cantera/cantera/pull/1520), [#1547](https://github.com/Cantera/cantera/pull/1547), [#1585](https://github.com/Cantera/cantera/pull/1585))
- Add "native" support for HDF5 as an input/output format for `SolutionArray` and 1D flames ([E166](https://github.com/Cantera/enhancements/issues/166), [`flame_initial_guess.py`](https://cantera.org/examples/python/onedim/flame_initial_guess.py.html))
- Add a new thermo model, `coverage-dependent-surface` for representing surfaces where the enthalpy, entropy, and heat capacity of each species may depend on its coverage and the coverage of other species in the phase. ([class `CoverageDependentSurfPhase`](https://cantera.org/documentation/docs-3.0/doxygen/html/db/d25/classCantera_1_1CoverageDependentSurfPhase.html#details), [E59](https://github.com/Cantera/enhancements/issues/59), [#1135](https://github.com/Cantera/cantera/pull/1135), [#1471](https://github.com/Cantera/cantera/pull/1471), [#1529](https://github.com/Cantera/cantera/pull/1529), [#1583](https://github.com/Cantera/cantera/pull/1583))
- Add support for surface chemistry to the plug flow reactor model ([classs `FlowReactor`](https://cantera.org/documentation/docs-3.0/sphinx/html/cython/zerodim.html#flowreactor), [`1D_pfr_surfchem.py`](https://cantera.org/examples/python/surface_chemistry/1D_pfr_surfchem.py.html), [`surf_pfr.py`](https://cantera.org/examples/python/reactors/surf_pfr.py.html), [#1490](https://github.com/Cantera/cantera/pull/1490))
- Add support for using real gas models (Redlich-Kwong and Peng-Robinson) with the 1D flame solver ([E109](https://github.com/Cantera/enhancements/issues/109), [#1079](https://github.com/Cantera/cantera/pull/1079))
- Introduction of the `yaml2ck` script, which converts Cantera's YAML mechanism format into the legacy Chemkin format. ([`yaml2ck.py`](https://cantera.org/documentation/docs-3.0/sphinx/html/cython/yaml_conversion.html), [E#52](https://github.com/Cantera/enhancements/issues/52), [#1286](https://github.com/Cantera/cantera/pull/1286), [#1365](https://github.com/Cantera/cantera/pull/1365), [#1420](https://github.com/Cantera/cantera/pull/1420))
- Add an experimental Python module where Cantera returns dimensional values as quantities using the `pint` package. This is currently available only for thermo methods ([module `cantera.with_units`](https://cantera.org/documentation/docs-3.0/sphinx/html/cython/units.html), [`isentropic_units.py`](https://cantera.org/examples/python/thermo/isentropic_units.py.html), [`rankine_units.py`](https://cantera.org/examples/python/thermo/rankine_units.py.html), [`sound_speed_units.py`](https://cantera.org/examples/python/thermo/sound_speed_units.py.html), [E#3](https://github.com/Cantera/enhancements/issues/3), [#991](https://github.com/Cantera/cantera/pull/991), [#1569](https://github.com/Cantera/cantera/pull/1569))
- Preview release of a new Matlab toolbox, with a rewritten API that makes use of modern Matlab features and replaces the difficult-to-maintain MEX-file based backend with one based on using `calllib` to interact directly with the Cantera C interface. (For the adventurous, see [`README.md`](https://github.com/Cantera/cantera/blob/main/interfaces/matlab_experimental/readme.md), [E#32](https://github.com/Cantera/enhancements/issues/32), [#1182](https://github.com/Cantera/cantera/pull/1182), [#1496](https://github.com/Cantera/cantera/pull/1496), [#1498](https://github.com/Cantera/cantera/pull/1498))
- Preview release of a new C interface. See [`README.md`](https://github.com/Cantera/cantera/blob/main/interfaces/dotnet/README.md) for more on what's implemented and how to contribute ([#1331](https://github.com/Cantera/cantera/pull/1331), [#1401](https://github.com/Cantera/cantera/pull/1401))

<details>
<summary><h2>Additional new features</strong></h2> (click here to expand)</summary>

- Add support for polynomial dependency of activation energy on surface species coverages ([documentation](https://cantera.org/documentation/docs-3.0/sphinx/html/yaml/reactions.html#interface-arrhenius), [1495](https://github.com/Cantera/cantera/pull/1495))
- Add speed of sound property to `ThermoPhase` objects ([`sound_speed.py`](https://cantera.org/examples/python/thermo/sound_speed.py.html), [#1491](https://github.com/Cantera/cantera/pull/1491))
- Implemented isothermal compressibility and thermal expansion coefficient calculations for Redlich-Kwong and Peng-Robinson equations of state ([E122](https://github.com/Cantera/enhancements/issues/122), [#1421](https://github.com/Cantera/cantera/pull/1421))
- Add `interfaceCurrent` (C++) and `interface_current` methods to `Kinetics` objects ([1398](https://github.com/Cantera/cantera/pull/1398))
- Add molecular weight attribute to `Species` objects ([1266](https://github.com/Cantera/cantera/pull/1266))
- Add `set_equivalence_ratio` and `set_mixture_fraction` methods to Python `Quantity` objects ([1517](https://github.com/Cantera/cantera/pull/1517))
- Add array size methods to Python `SolutionArray` class ([1284](https://github.com/Cantera/cantera/pull/1284))
- Add `Solution` class to `clib` ([1448](https://github.com/Cantera/cantera/pull/1448), [#1600](https://github.com/Cantera/cantera/pull/1600))
- Introduce factory for creating 1D domains (`newDomain` in C++, `domain_new` in `clib`) ([1445](https://github.com/Cantera/cantera/pull/1445))
- Introduce factory for creating functor objects (`newFunc1` in C++; `func_new_basic`, `func_new_advanced`, `func_new_compound`, and `func_new_modified` in `clib`; and `Func1.cxx_functor` in Python) ([documentation](https://cantera.org/documentation/docs-3.0/doxygen/html/dc/d4c/group__func1.html), [#1513](https://github.com/Cantera/cantera/pull/1513), [#1521](https://github.com/Cantera/cantera/pull/1521))
- Provide a more complete interface to the C++ `Units` class in Python ([1285](https://github.com/Cantera/cantera/pull/1285))
- Add a sample program demonstrating the use of the Cantera C interface, `clib` ([1454](https://github.com/Cantera/cantera/pull/1454))
- Add an example of modelling a porous media burner using the `ExtensibleReactor` class ([`PorousMediaBurner.py`](https://cantera.org/examples/python/reactors/PorousMediaBurner.py.html), [#1443](https://github.com/Cantera/cantera/pull/1443))
- Add an example demonstrating saving and loading of 1D flame simulations and restarting with different initial guesses ([`flame_initial_guess.py`](https://cantera.org/examples/python/onedim/flame_initial_guess.py.html), [#1293](https://github.com/Cantera/cantera/pull/1293))
- The test suite now includes a comprehensive set of thermodynamic consistency tests for all phase models ([E114](https://github.com/Cantera/enhancements/issues/114), [#1299](https://github.com/Cantera/cantera/pull/1299), [#1501](https://github.com/Cantera/cantera/pull/1501))
- Consolidate literature references in the C++ documentation into a [bibliography](https://cantera.org/documentation/docs-3.0/doxygen/html/d0/de3/citelist.html) ([#1550](https://github.com/Cantera/cantera/pull/1550), [#1575](https://github.com/Cantera/cantera/pull/1575))
- Enable linking to the Cantera shared library on Windows ([E140](https://github.com/Cantera/enhancements/issues/140), [#1429](https://github.com/Cantera/cantera/pull/1429))
- Split up compilation of the Python module to allow parallel builds and faster incremental builds ([1334](https://github.com/Cantera/cantera/pull/1334), [#1484](https://github.com/Cantera/cantera/pull/1484))
- Automatically detect and use optimized BLAS/LAPACK libraries when compiling ([E144](https://github.com/Cantera/enhancements/issues/144), [#1316](https://github.com/Cantera/cantera/pull/1316))
- Add new `core.h` header file to simplify required includes for high-level Cantera usage ([`demo.cpp`](https://cantera.org/examples/cxx/demo.html), [#1238](https://github.com/Cantera/cantera/pull/1238))
- Added support for Python 3.11 and dropped support for Python 3.7 ([1326](https://github.com/Cantera/cantera/pull/1326), [#1406](https://github.com/Cantera/cantera/pull/1406), [#1467](https://github.com/Cantera/cantera/pull/1467))
- Added support for SUNDIALS versions up to 6.6.0 and dropped support for SUNDIALS 2.x ([1341](https://github.com/Cantera/cantera/pull/1341), [#1570](https://github.com/Cantera/cantera/pull/1570))
- Add support for building MATLAB toolbox on Apple Silicon ([1524](https://github.com/Cantera/cantera/pull/1524))
- Added SCons option to set `AR` (for example, to use `llvm-ar` instead of `ar`) ([1424](https://github.com/Cantera/cantera/pull/1424))

</details><details><summary><h2>Changes to existing capabilities</strong></h2> (click here to expand)</summary>

- `BulkKinetics` now handles kinetics for any bulk phase, given the appropriate reaction rate parameterizations. As a result, `GasKinetics` is deprecated in favor of `BulkKinetics` ([1483](https://github.com/Cantera/cantera/pull/1483))
- Rename C++ phase setter mnemonics to use `D` for density instead of `R` for rho, for example `setState_TR` is deprecated in favor of `setState_TD` ([1433](https://github.com/Cantera/cantera/pull/1433))
- Introduce properties for certain reactor features in Python and deprecate the old getter/setter methods. `ReactorNet.initial_time` replaces `ReactorNet.set_initial_time()`, `Wall.velocity` replaces `Wall.set_velocity()`, `Wall.heat_flux` replaces `Wall.set_heat_flux()`, `Wall.expansion_rate` replaces `wall.vdot`, `Wall.heat_rate` replaces `wall.qdot()`, `Valve.time_function` replaces `Valve.set_time_function()`, `MassFlowController.pressure_function` replaces `MassFlowController.set_pressure_function()` and `PressureController.primary` replaces `PressureController.set_master()` ([E160](https://github.com/Cantera/enhancements/issues/160), [#1515](https://github.com/Cantera/cantera/pull/1515))
- Improve ability to find non-extinct diffusion flames when using the "auto" solver mode ([E155](https://github.com/Cantera/enhancements/issues/155), [#1463](https://github.com/Cantera/cantera/pull/1463))
- Guard against combining Python `Quantity` objects at constant enthalpy and pressure if their pressures aren't equal ([1517](https://github.com/Cantera/cantera/pull/1517))
- Allow transport geometry flags in Chemkin input files that are formatted as floating point values ([1396](https://github.com/Cantera/cantera/pull/1396))
- Disable irrelevant warnings for extinct diffusion flames ([1336](https://github.com/Cantera/cantera/pull/1336))
- Moved Python test suite and examples out of the Python module; they are no longer installed as part of the Cantera Python package. ([E51](https://github.com/Cantera/enhancements/issues/51), [#1352](https://github.com/Cantera/cantera/pull/1352), [#1354](https://github.com/Cantera/cantera/pull/1354))
- Drop support for generating `Makefile`s for samples ([1380](https://github.com/Cantera/cantera/pull/1380))
- Drop support for compiling in Cygwin ([E134](https://github.com/Cantera/enhancements/issues/134), [#1367](https://github.com/Cantera/cantera/pull/1367))
- Migrate to C++17 standard, make use of modern C++ features, and make various style improvements to the C++ code ([E181](https://github.com/Cantera/enhancements/issues/181), [E#184](https://github.com/Cantera/enhancements/issues/184), [#1246](https://github.com/Cantera/cantera/pull/1246), [#1327](https://github.com/Cantera/cantera/pull/1327), [#1346](https://github.com/Cantera/cantera/pull/1346), [#1438](https://github.com/Cantera/cantera/pull/1438), [#1441](https://github.com/Cantera/cantera/pull/1441), [#1452](https://github.com/Cantera/cantera/pull/1452), [#1507](https://github.com/Cantera/cantera/pull/1507), [#1565](https://github.com/Cantera/cantera/pull/1565), [#1568](https://github.com/Cantera/cantera/pull/1568), [#1571](https://github.com/Cantera/cantera/pull/1571), [#1589](https://github.com/Cantera/cantera/pull/1589))
- Numerous improvements to the organization and formatting of the Doxygen and Sphinx documentation, in part by using `doxygen-awesome` and the PyData Sphinx theme([E115](https://github.com/Cantera/enhancements/issues/115), [E#175](https://github.com/Cantera/enhancements/issues/175), [E#179](https://github.com/Cantera/enhancements/issues/179), [#1279](https://github.com/Cantera/cantera/pull/1279), [#1427](https://github.com/Cantera/cantera/pull/1427), [#1518](https://github.com/Cantera/cantera/pull/1518), [#1534](https://github.com/Cantera/cantera/pull/1534), [#1541](https://github.com/Cantera/cantera/pull/1541), [#1543](https://github.com/Cantera/cantera/pull/1543), [#1546](https://github.com/Cantera/cantera/pull/1546), [#1551](https://github.com/Cantera/cantera/pull/1551), [#1557](https://github.com/Cantera/cantera/pull/1557), [#1558](https://github.com/Cantera/cantera/pull/1558), [#1559](https://github.com/Cantera/cantera/pull/1559), [#1561](https://github.com/Cantera/cantera/pull/1561), [#1562](https://github.com/Cantera/cantera/pull/1562), [#1563](https://github.com/Cantera/cantera/pull/1563), [#1567](https://github.com/Cantera/cantera/pull/1567), [#1572](https://github.com/Cantera/cantera/pull/1572), [#1573](https://github.com/Cantera/cantera/pull/1573), [#1582](https://github.com/Cantera/cantera/pull/1582), [#1581](https://github.com/Cantera/cantera/pull/1581), [#1584](https://github.com/Cantera/cantera/pull/1584), [#1590](https://github.com/Cantera/cantera/pull/1590))
- Various improvements to the SCons build system ([1268](https://github.com/Cantera/cantera/pull/1268), [#1307](https://github.com/Cantera/cantera/pull/1307), [#1351](https://github.com/Cantera/cantera/pull/1351), [#1360](https://github.com/Cantera/cantera/pull/1360), [#1404](https://github.com/Cantera/cantera/pull/1404), [#1470](https://github.com/Cantera/cantera/pull/1470), [#1472](https://github.com/Cantera/cantera/pull/1472), [#1509](https://github.com/Cantera/cantera/pull/1509), [#1542](https://github.com/Cantera/cantera/pull/1542))
- Updates to simplify the special behavior that implements different 1D flame types and boundary conditions ([E165](https://github.com/Cantera/enhancements/issues/165), [E#171](https://github.com/Cantera/enhancements/issues/171), [#1477](https://github.com/Cantera/cantera/pull/1477), [#1514](https://github.com/Cantera/cantera/pull/1514), [#1523](https://github.com/Cantera/cantera/pull/1523), [#1531](https://github.com/Cantera/cantera/pull/1531), [#1555](https://github.com/Cantera/cantera/pull/1555))
- Make use of C++ `Solution` objects in `Domain1D` and related classes ([1345](https://github.com/Cantera/cantera/pull/1345), [#1384](https://github.com/Cantera/cantera/pull/1384), [#1444](https://github.com/Cantera/cantera/pull/1444), [#1594](https://github.com/Cantera/cantera/pull/1594), [#1598](https://github.com/Cantera/cantera/pull/1598))
- Improved error handling for clib `thermo_setDensity` and `thermo_setMolarDensity` methods ([1413](https://github.com/Cantera/cantera/pull/1413))
- Speed up Python module import by deferring imports of optional dependencies ([1428](https://github.com/Cantera/cantera/pull/1428))
- Link Python `list_data_files` to C++ `getDataDirectories` ([1358](https://github.com/Cantera/cantera/pull/1358))
- Remove features deprecated in Cantera 2.6. Principally, this includes legacy reaction rate types ([1292](https://github.com/Cantera/cantera/pull/1292)) and the CTI/XML input formats ([#1291](https://github.com/Cantera/cantera/pull/1291))
- Deprecate remaining specializations of `Reaction` class and obsolete methods that were used by legacy reaction rate evaluators ([E149](https://github.com/Cantera/enhancements/issues/149), [#1295](https://github.com/Cantera/cantera/pull/1295), [#1333](https://github.com/Cantera/cantera/pull/1333))
- Deprecate other untested, unused and/or obsolete code ([C++ Deprecations](https://cantera.org/documentation/docs-3.0/doxygen/html/da/d58/deprecated.html), [#1455](https://github.com/Cantera/cantera/pull/1455), [#1504](https://github.com/Cantera/cantera/pull/1504))
- Improve deprecation warnings issued from Python to include the name of the deprecated method and to show the line where that function is called from ([1519](https://github.com/Cantera/cantera/pull/1519))

</details>
<details><summary><h2>Bugs Fixed</strong></h2> (click here to expand)</summary>

- Fixed thermodynamic consistency issues with `SurfPhase` and `RedlichKisterVPSSTP` ([1449](https://github.com/Cantera/cantera/pull/1449))
- Fixed thermodynamic consistency errors in IAPWS water equation of state ([1394](https://github.com/Cantera/cantera/pull/1394))
- Fixed thermodynamic consistency issues in `IdealSolidSolnPhase` and `BinarySolutionTabulatedThermo` ([1442](https://github.com/Cantera/cantera/pull/1442))
- Fix calculation of electron enthalpy contribution in `PlasmaPhase` ([1323](https://github.com/Cantera/cantera/pull/1323))
- Fix setting reference pressure for a phase by setting the reference pressure of the individual species ([1503](https://github.com/Cantera/cantera/pull/1503))
- Fix issues with "volume" and compressibility of `SurfPhase` ([1350](https://github.com/Cantera/cantera/pull/1350))
- Handle factorization errors in equilibrium initial estimator ([1479](https://github.com/Cantera/cantera/pull/1479))
- Make helpful errors for invalid reactions work more consistently ([1330](https://github.com/Cantera/cantera/pull/1330), [#1356](https://github.com/Cantera/cantera/pull/1356))
- Fix serialization of phases with reactions from multiple YAML sections ([1552](https://github.com/Cantera/cantera/pull/1552))
- Fix loading serialized mechanisms where reactions contain undeclared third bodies ([1588](https://github.com/Cantera/cantera/pull/1588))
- Fix cases where three-body reactions were not being automatically detected ([1338](https://github.com/Cantera/cantera/pull/1338))
- Fix possible segfaults when using Python `CustomRate` ([1293](https://github.com/Cantera/cantera/pull/1293))
- Partial fix for PLOG validation at low temperatures ([1553](https://github.com/Cantera/cantera/pull/1553))
- Fix default `atol` used in `ReactorNet.advance_to_steady_state` ([1305](https://github.com/Cantera/cantera/pull/1305))
- Fix reading arrays containing subnormal floating point values ([1545](https://github.com/Cantera/cantera/pull/1545))
- Fix adding Python `Quantity` objects when using molar basis ([1517](https://github.com/Cantera/cantera/pull/1517))
- Add missing array properties to `SolutionArray` and `FlameBase` ([1342](https://github.com/Cantera/cantera/pull/1342))
- Fix [`surf_pfr_chain.py`](https://cantera.org/examples/python/reactors/surf_pfr_chain.py.html) example to avoid misleading use of perturbed `Solution` objects ([#1304](https://github.com/Cantera/cantera/pull/1304))
- Fix Matlab samples to resolve issues from transition to YAML input files ([1414](https://github.com/Cantera/cantera/pull/1414))
- Fix numerous build issues for certain configurations and platforms ([1272](https://github.com/Cantera/cantera/pull/1272), [#1362](https://github.com/Cantera/cantera/pull/1362), [#1364](https://github.com/Cantera/cantera/pull/1364), [#1366](https://github.com/Cantera/cantera/pull/1366), [#1378](https://github.com/Cantera/cantera/pull/1378), [#1381](https://github.com/Cantera/cantera/pull/1381), [#1390](https://github.com/Cantera/cantera/pull/1390), [#1434](https://github.com/Cantera/cantera/pull/1434), [#1437](https://github.com/Cantera/cantera/pull/1437), [#1505](https://github.com/Cantera/cantera/pull/1505), [#1511](https://github.com/Cantera/cantera/pull/1511), [#1538](https://github.com/Cantera/cantera/pull/1538), [#1544](https://github.com/Cantera/cantera/pull/1544), [#1574](https://github.com/Cantera/cantera/pull/1574), [#1591](https://github.com/Cantera/cantera/pull/1591))
- Various documentation updates ([1276](https://github.com/Cantera/cantera/pull/1276), [#1296](https://github.com/Cantera/cantera/pull/1296), [#1328](https://github.com/Cantera/cantera/pull/1328), [#1335](https://github.com/Cantera/cantera/pull/1335))

</details>

Contributors

This release was made possible by the following contributors: [anthony-walker](https://github.com/anthony-walker), [arghdos](https://github.com/arghdos), [band-a-prend](https://github.com/band-a-prend), [BangShiuh](https://github.com/BangShiuh), [bryanwweber](https://github.com/bryanwweber), [burkenyo](https://github.com/burkenyo), [c-randall](https://github.com/c-randall), [cdeil](https://github.com/cdeil), [chinahg](https://github.com/chinahg), [corykinney](https://github.com/corykinney), [decaluwe](https://github.com/decaluwe), [g3bk47](https://github.com/g3bk47), [gkogekar](https://github.com/gkogekar), [hallaali](https://github.com/hallaali), [ischoegl](https://github.com/ischoegl), [jongyoonbae](https://github.com/jongyoonbae), [kyleniemeyer](https://github.com/kyleniemeyer), [mefuller](https://github.com/mefuller), [rwest](https://github.com/rwest), [speth](https://github.com/speth), [ssun30](https://github.com/ssun30), [tsikes](https://github.com/tsikes), [yeanment](https://github.com/yeanment), [yurivict](https://github.com/yurivict)

See notes for [Cantera 3.0.0](https://github.com/Cantera/cantera/releases/tag/v3.0.0).

The Cantera development team is pleased to announce the availability of Cantera 2.6.0. There have been over 1400 commits to Cantera since the last version, 2.5.1, which was released in February 2021. We have closed or merged [162 pull requests](https://github.com/Cantera/cantera/pulls?q=is%3Apr+merged%3A2021-02-13..2022-05-01+is%3Aclosed) and closed [101 issues](https://github.com/Cantera/cantera/issues?page=4&q=is%3Aissue+closed%3A2021-02-13..2022-05-01+is%3Aclosed).

New features, bug fixes, and other changes

Highlights
- Major redesign of how reaction rates are handled internally to improve extensibility and enable new capabilities ([E63](https://github.com/Cantera/enhancements/issues/63), [E#87](https://github.com/Cantera/enhancements/issues/87), [#982](https://github.com/Cantera/cantera/pull/982), [#995](https://github.com/Cantera/cantera/pull/995), [#1061](https://github.com/Cantera/cantera/pull/1061), [#1101](https://github.com/Cantera/cantera/pull/1101), [#1151](https://github.com/Cantera/cantera/pull/1151), [#1153](https://github.com/Cantera/cantera/pull/1153), [#1181](https://github.com/Cantera/cantera/pull/1181), [#1183](https://github.com/Cantera/cantera/pull/1183), [#1184](https://github.com/Cantera/cantera/pull/1184), [#1187](https://github.com/Cantera/cantera/pull/1187), [#1202](https://github.com/Cantera/cantera/pull/1202), [#1216](https://github.com/Cantera/cantera/pull/1216), [#1223](https://github.com/Cantera/cantera/pull/1223), [#1225](https://github.com/Cantera/cantera/pull/1225), [#1256](https://github.com/Cantera/cantera/pull/1256), [#1257](https://github.com/Cantera/cantera/pull/1257))
- Enable delegation of reactor implementation to user-provided Python classes ([`custom2.py`](https://github.com/Cantera/cantera/blob/main/interfaces/cython/cantera/examples/reactors/custom2.py), [#1003](https://github.com/Cantera/cantera/pull/1003))
- Enable serialization of Cantera objects to YAML ([`mechanism_reduction.py`](https://github.com/Cantera/cantera/blob/main/interfaces/cython/cantera/examples/kinetics/mechanism_reduction.py), [#984](https://github.com/Cantera/cantera/pull/984), [#1014](https://github.com/Cantera/cantera/pull/1014), [#1031](https://github.com/Cantera/cantera/pull/1031))
- Implement pickling of Python Solution objects ([692](https://github.com/Cantera/cantera/pull/692))
- Add [PyPI](https://pypi.org/project/Cantera/) package for Cantera, installable with `pip`([#1075](https://github.com/Cantera/cantera/pull/1075), [#1239](https://github.com/Cantera/cantera/pull/1239), [#1240](https://github.com/Cantera/cantera/pull/1240), [#1232](https://github.com/Cantera/cantera/pull/1232), [#1261](https://github.com/Cantera/cantera/pull/1261))
- Implement Peng-Robinson equation of state for real gases ([1047](https://github.com/Cantera/cantera/pull/1047), [#1141](https://github.com/Cantera/cantera/pull/1141), [#1180](https://github.com/Cantera/cantera/pull/1180))
- Add Blowers-Masel reaction rate parameterization for gas phase and interface kinetics ([`blowers-masel.py`](https://github.com/Cantera/cantera/blob/main/interfaces/cython/cantera/examples/kinetics/blowers_masel.py), [#987](https://github.com/Cantera/cantera/pull/987))
- Add calculation of sparse, analytical Jacobians for gas kinetics ([`derivative_speed.cpp`](https://github.com/Cantera/cantera/blob/main/samples/cxx/jacobian/derivative_speed.cpp), [#1088](https://github.com/Cantera/cantera/pull/1088), [#1089](https://github.com/Cantera/cantera/pull/1089), [#1212](https://github.com/Cantera/cantera/pull/1212))
- Add new phase type and reaction rate parameterizations for plasmas with independent electron temperature ([1099](https://github.com/Cantera/cantera/pull/1099), [#1166](https://github.com/Cantera/cantera/pull/1166), [#1190](https://github.com/Cantera/cantera/pull/1190))

<details>
<summary><strong>Click here for details on additional new features, changes to existing capabilities, and fixed bugs</strong></summary>

New features
- Simplify creation of interface phases and their adjacent bulk phases ([1169](https://github.com/Cantera/cantera/pull/1169), [#1247](https://github.com/Cantera/cantera/pull/1247))
- Add Tsang "falloff" function [1090](https://github.com/Cantera/cantera/pull/1090)
- Add option to allow unnormalized and/or negative mass/mole fractions in SolutionArray / 1D flame importers [1037](https://github.com/Cantera/cantera/pull/1037)
- Added access functions to polynomial fits of gas transport properties [817](https://github.com/Cantera/cantera/pull/817), [#1077](https://github.com/Cantera/cantera/pull/1077)
- Add dilution options to equivalence ratio functions in Python [1206](https://github.com/Cantera/cantera/pull/1206)
- Make rate coefficient and standard concentration units available in Python [1076](https://github.com/Cantera/cantera/pull/1076)
- Add creation of Species from Python dict [1179](https://github.com/Cantera/cantera/pull/1179)
- Add thermal conductivity to DustyGas in Python [988](https://github.com/Cantera/cantera/pull/988)
- Add `set_mixture_fraction` method to `SolutionArray` [1242](https://github.com/Cantera/cantera/pull/1242)
- Exposed some additional functions to the Fortran interface [1154](https://github.com/Cantera/cantera/pull/1154)
- New C++ custom ODEs example [922](https://github.com/Cantera/cantera/pull/922)
- Added a Python version of the Matlab lithium ion battery example [1263](https://github.com/Cantera/cantera/pull/1263)
- Add support for Sundials 6.0 [1162](https://github.com/Cantera/cantera/pull/1162)

Changes to existing capabilities
- Use YAML for saving and loading 1D flame simulations, replacing the XML output format [1112](https://github.com/Cantera/cantera/pull/1112), [#1140](https://github.com/Cantera/cantera/pull/1140)
- Use normal sign convention for reactor heat transfer [1156](https://github.com/Cantera/cantera/pull/1156)
- Separate third-body concentration term from rate constant for three body reactions [1084](https://github.com/Cantera/cantera/pull/1084)
- Translate C++ warnings to Python [1201](https://github.com/Cantera/cantera/pull/1201)
- Refactor SCons option handling and automatically extract compilation options for website documentation [1137](https://github.com/Cantera/cantera/pull/1137)
- Automatically use dependencies from and install into an active Conda environment [1191](https://github.com/Cantera/cantera/pull/1191)
- Include header description in when converting from CTI to YAML [1205](https://github.com/Cantera/cantera/pull/1205)
- Use of deprecated XML or CTI formats now actively issues warnings [1159](https://github.com/Cantera/cantera/pull/1159)
- Support legacy ruamel.yaml loaders [1060](https://github.com/Cantera/cantera/pull/1060)
- Update examples to use "h2o2.yaml" instead of GRI 3.0 [1109](https://github.com/Cantera/cantera/pull/1109)
- Prevent inadvertent attribute assignment in Quantity [1124](https://github.com/Cantera/cantera/pull/1124)
- Fix issues with composition strings and kinetics model of "None" in cti2yaml [1127](https://github.com/Cantera/cantera/pull/1127)
- Deprecate shell setup scripts (`setup_cantera`) [1189](https://github.com/Cantera/cantera/pull/1189)
- Replace deprecated yaml.safe_load / simplify paths [1049](https://github.com/Cantera/cantera/pull/1049)
- Read YAML using C++ newSolution in Python / access root level data [1129](https://github.com/Cantera/cantera/pull/1129)
- Improve YAML formatting of floating point values and multiline strings [1133](https://github.com/Cantera/cantera/pull/1133)
- Automatically detect unspecified third-body collision partners [1015](https://github.com/Cantera/cantera/pull/1015)
- Various compilation, build system, and test infrastructure updates [979](https://github.com/Cantera/cantera/pull/979), [#994](https://github.com/Cantera/cantera/pull/994), [#1000](https://github.com/Cantera/cantera/pull/1000), [#1004](https://github.com/Cantera/cantera/pull/1004), [#1012](https://github.com/Cantera/cantera/pull/1012), [#1020](https://github.com/Cantera/cantera/pull/1020), [#1025](https://github.com/Cantera/cantera/pull/1025), [#1034](https://github.com/Cantera/cantera/pull/1034), [#1043](https://github.com/Cantera/cantera/pull/1043), [#1056](https://github.com/Cantera/cantera/pull/1056), [#1062](https://github.com/Cantera/cantera/pull/1062), [#1145](https://github.com/Cantera/cantera/pull/1145), [#1158](https://github.com/Cantera/cantera/pull/1158), [#1102](https://github.com/Cantera/cantera/pull/1102), [#1119](https://github.com/Cantera/cantera/pull/1119), [#1122](https://github.com/Cantera/cantera/pull/1122), [#1144](https://github.com/Cantera/cantera/pull/1144). [#1167](https://github.com/Cantera/cantera/pull/1167), [#1172](https://github.com/Cantera/cantera/pull/1172), [#1176](https://github.com/Cantera/cantera/pull/1176), [#1178](https://github.com/Cantera/cantera/pull/1178), [#1197](https://github.com/Cantera/cantera/pull/1197), [#1208](https://github.com/Cantera/cantera/pull/1208), [#1222](https://github.com/Cantera/cantera/pull/1222), [#1229](https://github.com/Cantera/cantera/pull/1229), [#1241](https://github.com/Cantera/cantera/pull/1241), [#1268](https://github.com/Cantera/cantera/pull/1268)
- Various documentation updates [983](https://github.com/Cantera/cantera/pull/983), [#1002](https://github.com/Cantera/cantera/pull/1002), [#1022](https://github.com/Cantera/cantera/pull/1022), [#1032](https://github.com/Cantera/cantera/pull/1032), [#1045](https://github.com/Cantera/cantera/pull/1045), [#1065](https://github.com/Cantera/cantera/pull/1065), [#1121](https://github.com/Cantera/cantera/pull/1121), [#1142](https://github.com/Cantera/cantera/pull/1142), [#1152](https://github.com/Cantera/cantera/pull/1152), [#1196](https://github.com/Cantera/cantera/pull/1196), [#1200](https://github.com/Cantera/cantera/pull/1200), [#1227](https://github.com/Cantera/cantera/pull/1227), [#1231](https://github.com/Cantera/cantera/pull/1231), [#1234](https://github.com/Cantera/cantera/pull/1234), [#1249](https://github.com/Cantera/cantera/pull/1249), [#1255](https://github.com/Cantera/cantera/pull/1255), [#1264](https://github.com/Cantera/cantera/pull/1264)

Bugs fixed
- Fix Redlich-Kwong partial molar properties [1218](https://github.com/Cantera/cantera/pull/1218)
- Fix pressure dependence in IdealSolidSolnPhase::getPartialMolarEnthalpies [1087](https://github.com/Cantera/cantera/pull/1087)
- Fix evaluation of delta-star polynomials [1125](https://github.com/Cantera/cantera/pull/1125)
- Consistently use physical concentrations when calculating third body and falloff reaction rates, for both specifically enumerated efficiencies and generic third body colliders [968](https://github.com/Cantera/cantera/pull/968)
- Add check for sticking coefficient more than 1 [1038](https://github.com/Cantera/cantera/pull/1038)
- Fix typo in equivalenceRatio.py that resulted in printing wrong results [1173](https://github.com/Cantera/cantera/pull/1173)
- Fix memory error when deallocating Python reaction rate wrappers [1030](https://github.com/Cantera/cantera/pull/1030)
- Prevent segmentation fault when initializing standalone Reactor objects [1063](https://github.com/Cantera/cantera/pull/1063)
- Fix extinction temperature definition in diffusion_flame_extinction.py example [1066](https://github.com/Cantera/cantera/pull/1066)
- Fix handling of 'CK_Multi' transport model in flame simulations [1069](https://github.com/Cantera/cantera/pull/1069)
- Fix issues with import of SolutionArray from CSV [1074](https://github.com/Cantera/cantera/pull/1074)
- Fix SolutionArray.append [1086](https://github.com/Cantera/cantera/pull/1086)
- Fix 1D solver errors when reporting singular Jacobian and use of non-default tolerances after automatic grid expansion [1103](https://github.com/Cantera/cantera/pull/1103)
- Suppress output from setEnergy.m [1106](https://github.com/Cantera/cantera/pull/1106)
- Fix using reactors with both surface and gas phase chemistry with YAML input [981](https://github.com/Cantera/cantera/pull/981)
- Fix saving 1D output when radiative_heat_loss is enabled [993](https://github.com/Cantera/cantera/pull/993)
- Fix CTI to YAML conversion for transport='None' [997](https://github.com/Cantera/cantera/pull/997)
- Fix handling of CK mechanisms with '+M' in PLOG reaction equations [1252](https://github.com/Cantera/cantera/pull/1252)
- Fix detection of skipped/undeclared species in three body reactions [1027](https://github.com/Cantera/cantera/pull/1027)
- Fix invalid unchecked cast to StFlow [1226](https://github.com/Cantera/cantera/pull/1226)
- Fix `SolutionArray` extra slice [1204](https://github.com/Cantera/cantera/pull/1204)
- Check for valid component name when setting reactor advance limits [1215](https://github.com/Cantera/cantera/pull/1215)
- Fix incorrect temperature bounds and missing entries in NASA_condensed.yaml [1248](https://github.com/Cantera/cantera/pull/1248), [#1250](https://github.com/Cantera/cantera/pull/1250)
- Fix logic error in CanteraTest.assertNear [1120](https://github.com/Cantera/cantera/pull/1120)
- Fix various compilation / installation issues [980](https://github.com/Cantera/cantera/pull/980), [#1011](https://github.com/Cantera/cantera/pull/1011), [#1052](https://github.com/Cantera/cantera/pull/1052), [#1057](https://github.com/Cantera/cantera/pull/1057), [#1100](https://github.com/Cantera/cantera/pull/1100), [#1105](https://github.com/Cantera/cantera/pull/1105), [#1107](https://github.com/Cantera/cantera/pull/1107), [#1110](https://github.com/Cantera/cantera/pull/1110), [#1116](https://github.com/Cantera/cantera/pull/1116), [#1123](https://github.com/Cantera/cantera/pull/1123), [#1148](https://github.com/Cantera/cantera/pull/1148), [#1161](https://github.com/Cantera/cantera/pull/1161), [#1168](https://github.com/Cantera/cantera/pull/1168), [#1171](https://github.com/Cantera/cantera/pull/1171), [#1265](https://github.com/Cantera/cantera/pull/1265)
</details>

The complete list of changes can be found on the Cantera Wiki page: https://github.com/Cantera/cantera/wiki/Cantera-2.6.0-Changelog

Installation

Instructions for installing Cantera 2.6 are available on the [Cantera website](https://cantera.org/install/index.html). Available options include Conda; pip; native installers for Windows and macOS; packages for Ubuntu, Fedora/Enterprise Linux, Gentoo, and FreeBSD; and compiling from source.

Contributors
This release was made possible by the following contributors: [anthony-walker](https://github.com/anthony-walker), [band-a-prend](https://github.com/band-a-prend), [BangShiuh](https://github.com/BangShiuh), [blackrabbit17](https://github.com/blackrabbit17), [bryanwweber](https://github.com/bryanwweber), [12Chao](https://github.com/12Chao), [chinahg](https://github.com/chinahg), [DavidAkinpelu](https://github.com/DavidAkinpelu), [d-e-t](https://github.com/d-e-t), [decaluwe](https://github.com/decaluwe), [dschmider-HSOG](https://github.com/Cantera/cantera/commits?author=dschmider-HSOG), [g3bk47](https://github.com/g3bk47), [gkogekar](https://github.com/gkogekar), [ischoegl](https://github.com/ischoegl), [jongyoonbae](https://github.com/jongyoonbae), [lavdwall](https://github.com/lavdwall), [leesharma](https://github.com/leesharma), [mefuller](https://github.com/mefuller), [paulblum](https://github.com/paulblum), [santoshshanbhogue](https://github.com/santoshshanbhogue), [speth](https://github.com/speth), [stijn76](https://github.com/stijn76), [tpg2114](https://github.com/tpg2114)

The Cantera development team is pleased to announce the general availability of the second beta for the next release of Cantera, v2.6.0. There have been over 1300 commits to Cantera since the last version, 2.5.1, which was released in February 2021. We have closed or merged [143 pull requests](https://github.com/Cantera/cantera/pulls?q=is%3Apr+merged%3A2021-02-13..2022-04-10+is%3Aclosed) and closed [90 issues](https://github.com/Cantera/cantera/issues?q=is%3Aissue+closed%3A2021-02-13..2022-04-10+is%3Aclosed). Some of the highlights for this release are:
- Major redesign of how reaction rates are handled internally to improve extensibility and enable new capabilities ([E63](https://github.com/Cantera/enhancements/issues/63), [E#87](https://github.com/Cantera/enhancements/issues/87))
- Enable delegation of reactor implementation to user-provided Python classes ([`custom2.py`](https://github.com/Cantera/cantera/blob/main/interfaces/cython/cantera/examples/reactors/custom2.py))
- Enable serialization of Cantera objects to YAML ([`mechanism_reduction.py`](https://github.com/Cantera/cantera/blob/main/interfaces/cython/cantera/examples/kinetics/mechanism_reduction.py))
- Implement pickling of Python Solution objects
- Add [PyPI](https://pypi.org/project/Cantera/) package for Cantera, installable with `pip`
- Implement Peng-Robinson equation of state for real gases
- Add Blowers-Masel reaction rate parameterization for gas phase and interface kinetics ([`blowers-masel.py`](https://github.com/Cantera/cantera/blob/main/interfaces/cython/cantera/examples/kinetics/blowers_masel.py))
- Add calculation of sparse, analytical Jacobians for gas kinetics ([`derivative_speed.cpp`](https://github.com/Cantera/cantera/blob/main/samples/cxx/jacobian/derivative_speed.cpp))
- Add reaction rate parameterizations for plasmas with independent electron temperature

The complete list of changes can be found on the Cantera Wiki page: https://github.com/Cantera/cantera/wiki/Cantera-2.6.0-Changelog

Installation

Installation instructions for the Python module, Matlab toolbox, C++ interface, and Fortran 90 module on supported platforms are available at https://testing.cantera.org/install/index.html. Please note that as of 2022-04-11, installers for the beta are available via [PyPI](https://pypi.org/project/Cantera/) (using `pip`), the `cantera` conda channel, the [`cantera-team/cantera-unstable`](https://launchpad.net/~cantera-team/+archive/ubuntu/cantera-unstable) Ubuntu PPA, and the installers below. Additional installers will be available soon.

Contributors

This release was made possible by the following contributors: [12Chao](https://github.com/12Chao), [BangShiuh](https://github.com/BangShiuh), [blackrabbit17](https://github.com/blackrabbit17), [DavidAkinpelu](https://github.com/DavidAkinpelu), [anthony-walker](https://github.com/anthony-walker), [band-a-prend](https://github.com/band-a-prend), [bryanwweber](https://github.com/bryanwweber), [chinahg](https://github.com/chinahg), [d-e-t](https://github.com/d-e-t), [decaluwe](https://github.com/decaluwe), [g3bk47](https://github.com/g3bk47), [gkogekar](https://github.com/gkogekar), [ischoegl](https://github.com/ischoegl), [jongyoonbae](https://github.com/jongyoonbae), [lavdwall](https://github.com/lavdwall), [leesharma](https://github.com/leesharma), [mefuller](https://github.com/mefuller), [paulblum](https://github.com/paulblum), [speth](https://github.com/speth), [stijn76](https://github.com/stijn76), [tpg2114](https://github.com/tpg2114)

The Cantera development team is pleased to announce the general availability of the first beta for the next release of Cantera, v2.6.0. There have been over 1300 commits to Cantera since the last version, 2.5.1, which was released in February 2021. We have closed or merged [136 pull requests](https://github.com/Cantera/cantera/pulls?q=is%3Apr+merged%3A2021-02-13..2022-03-26+is%3Aclosed) and closed [87 issues](https://github.com/Cantera/cantera/issues?page=4&q=is%3Aissue+closed%3A2021-02-13..2022-03-26+is%3Aclosed). Some of the highlights for this release are:
- Major redesign of how reaction rates are handled internally to improve extensibility and enable new capabilities ([E63](https://github.com/Cantera/enhancements/issues/63), [E#87](https://github.com/Cantera/enhancements/issues/87))
- Enable delegation of reactor implementation to user-provided Python classes ([`custom2.py`](https://github.com/Cantera/cantera/blob/main/interfaces/cython/cantera/examples/reactors/custom2.py))
- Enable serialization of Cantera objects to YAML ([`mechanism_reduction.py`](https://github.com/Cantera/cantera/blob/main/interfaces/cython/cantera/examples/kinetics/mechanism_reduction.py))
- Implement pickling of Python Solution objects
- Add [PyPI](https://pypi.org/project/Cantera/) package for Cantera, installable with `pip`
- Implement Peng-Robinson equation of state for real gases
- Add Blowers-Masel reaction rate parameterization for gas phase and interface kinetics ([`blowers-masel.py`](https://github.com/Cantera/cantera/blob/main/interfaces/cython/cantera/examples/kinetics/blowers_masel.py))
- Add calculation of sparse, analytical Jacobians for gas kinetics ([`derivative_speed.cpp`](https://github.com/Cantera/cantera/blob/main/samples/cxx/jacobian/derivative_speed.cpp))
- Add reaction rate parameterizations for plasmas with independent electron temperature

The complete list of changes can be found on the Cantera Wiki page: https://github.com/Cantera/cantera/wiki/Cantera-2.6.0-Changelog

This release was made possible by the following contributors: [12Chao](https://github.com/12Chao), [BangShiuh](https://github.com/BangShiuh), [blackrabbit17](https://github.com/blackrabbit17), [DavidAkinpelu](https://github.com/DavidAkinpelu), [anthony-walker](https://github.com/anthony-walker), [band-a-prend](https://github.com/band-a-prend), [bryanwweber](https://github.com/bryanwweber), [chinahg](https://github.com/chinahg), [d-e-t](https://github.com/d-e-t), [decaluwe](https://github.com/decaluwe), [g3bk47](https://github.com/g3bk47), [gkogekar](https://github.com/gkogekar), [ischoegl](https://github.com/ischoegl), [jongyoonbae](https://github.com/jongyoonbae), [lavdwall](https://github.com/lavdwall), [leesharma](https://github.com/leesharma), [mefuller](https://github.com/mefuller), [paulblum](https://github.com/paulblum), [speth](https://github.com/speth), [stijn76](https://github.com/stijn76), [tpg2114](https://github.com/tpg2114)