Cantera 2.4.0

Cantera 2.4.0

We are pleased to announce the release of Cantera 2.4.0. Cantera 2.4.0 includes more than 380 commits to the code since 2.3.0, merges more than 70 pull requests, and closes almost 60 issues. In this release, we improved the maintainability of Cantera by removing or deprecating old, untested code, moving the website and Mixmaster to separate repositories, and automating more of the build/testing process. We also added new features to the 1-D reactor code (among other areas), including adding an ionized gas transport class and the IonFlow and BurnerIonFlame classes, providing better accessing to callbacks during 1-D solutions, and automatically detecting certain common failure conditions of the 1-D solver. This release of Cantera was made possible by contributions from 14 developers: @speth, @bryanwweber, @BangShiuh, @decaluwe, @wandadars, @jsantner, @arghdos, @rwest, @g3bk47, @awehrfritz, @band-a-prend, @vdevgan, @KyleLinevitchJr, and @MarcDuQuesne.

For installation and compilation instructions for Cantera 2.4.0, please see the directions on the Cantera website. In addition to Conda packages, Windows installers, and Ubuntu packages, this release also features the addition of a pre-compiled Matlab toolbox for macOS users, replacing Homebrew as the prefered method of installing Cantera for Matlab on macOS.

Thanks to a small development grant from NumFOCUS (see more about NumFOCUS below), @bryanwweber and @decaluwe reorganized and restyled the Cantera website. The website has moved to a separate repository, allowing the website content to be updated without modifications to the main Cantera source code. We also tried to make it easy for all of our users to find what they're looking for quickly, from installation instructions and tutorials for beginners, to advanced examples and API documentation for experienced Cantera programmers. The new website also redirects all traffic to HTTPS, ensuring a secure experience for everyone.

Cantera is now officially part of NumFOCUS. NumFOCUS is a 501(c)3 nonprofit dedicated to supporting the open source scientific computing community. If you are interested in learning more about NumFOCUS, please visit their website at, or our website at

Cantera 2.4.0 is the last release that will be compatible with Python 2.7. Support for Python 2.7 from the Python Software Foundation will end January 1, 2020. Given the recent release cadence of Cantera, the next major version of Cantera will probably be released very close to that date, so we have made the decision to drop Python 2.7 support for Cantera 2.5.0 and higher.

One notable change to the build requirements for Cantera 2.4.0 is that SCons 3.0.0 or higher must be used to compile the source code. This means that either Python 2 or Python 3 can be used to run SCons. In addition, there are now three options to handle building the Python interface, depending on whether the user wants to build for Python 2 or Python 3. Please check the documentation or run scons help for more information.

Summary of changes in Cantera 2.4.0

For a complete changelog, see the Github release page. Major changes are summarized below.

Bugs fixed

  • Fix inconstencies and bugs in several ThermoPhase derived classes, including PDSS_IdealGas, IonsFromNeutralVPSSTP, PDSS_IonsFromNeutral, PDSS_HKFT, LatticePhase, PDSS_SSVol, ConstDensityThermo, and PureFluidPhase
  • Preserve constant property pair when multiplying Quantity objects
  • Fix using pure fluids in reactors
  • Add temperature dependence of rotational relaxation in transport calculations
  • Disable linking to external SUNDIALS libraries when building the Matlab toolbox

Changes to existing capabilities

  • Allow instantiation of ThermoPhase derived classes without XML
  • set_equivalence_ratio now supports sulfur oxidation
  • Make all complex object types (ThermoPhase, Kinetics, Transport, Reactor, Domain1D, etc.) objects non-copyable
  • Deprecate FreeFlow and AxiStagnFlow classes by moving the relevant functions into the StFlow class
  • Allow convertMech function to be called multiple times
  • Remove the requirement for users to have Boost headers installed when building against the Cantera library
  • Change the options to build the Python interface, since SCons can be run by Python 3
  • Update GTest, fmtlib, SUNDIALS, and Eigen submodule versions


  • Add ion gas transport model, and IonFlow and BurnerIonFlame flame classes
  • Add C++ OpenMP, Non-Ideal Shock Tube, PSR/WSR, and time-dependent mass flow rate examples
  • Add class AnyMap
  • Allow negative reaction orders
  • Add unity Lewis number transport model
  • Add electron to the built-in elements
  • Add get_equivalence_ratio function