KineticGas is available on PyPi as the pykingas package, for python versions 3.8-3.11, compiled for MacOS running on Apple Silicon, Linux and Windows.

For MacOS running on Intel, or other operating systems, KineticGas must currently be built from source.

Dependencies

The Python package dependencies are listed in the setup.py file in the root directory of the package.

To compile the binary that is called from the python wrapper, pybind11 is required.

A standalone C++ module, that works without the python wrapper is currently under development. See branches under pure_cpp/ for the most up-to-date version there.

Building from source

A build system using cmake and make is set up to support Mac, Linux and Windows. For Mac machines running on intel chips, one compiler flag must be modified.

First Try - For Mac/Linux

If all goes well, running

bash cpp/build.sh
pip install .

From the top level directory should provide you with an installation of the KineticGas python package pykingas.

For Mac’s running on an intel chip, the compiler flag -arch arm64 which is set in cpp/CMakeLists.txt must be removed or changed to -arch x86_64.

Short explanation

The bash script cpp/build_kingas.sh uses cmake and make to compile the binary that is called from the python module. Then it moves the binary to the pykingas directory.

When something goes wrong

• The variable PYBIND11_ROOT, set in cpp/CMakeLists.txt must contain the path to the root directory of your pybind11 installation.
  • If you don’t have pybind11:
    • Run git clone https://github.com/pybind/pybind11.git
    • Set PYBIND11_ROOT in cpp/CMakeLists.txt to the resulting directory.
• The system arcitecture to compile for, and the python version, are specified in cpp/CMakeLists.txt, modify these as needed.
• The bash script cpp/build.sh sets the environment variables CC and CXX, these may also need to be modified for your system.
• The python installation to build against can be specified with
  • bash cpp/build.sh -DPYTHON_EXECUTABLE=<path/to/python>
  • Where <path/to/python> can (usually) be replaced by $(which python).
  • Alternatively, add the line set(PYBIND11_PYTHON_VERSION 3) to the top of the file cpp/CMakeLists.txt
  • Or: add the line set(PYTHON_EXECUTABLE "<path/to/python>)"
• If cmake starts looping infinitely:
  • You may be getting a message of the type :

    You have changed variables that require your cache to be deleted.
    Configure will be re-run and you may have to reset some variables.
    The following variables have changed:
    CMAKE_C_COMPILER= /Library/Developer/CommandLineTools/usr/bin/cc
    CMAKE_CXX_COMPILER= /Library/Developer/CommandLineTools/usr/bin/c++
    CMAKE_CXX_COMPILER= /Library/Developer/CommandLineTools/usr/bin/c++
    

  • To fix this: Ensure that there are no set(CMAKE_CXX_COMPILER <path/to/compiler>) or set(CMAKE_C_COMPILER <path/to/compiler>) statements in cpp/CMakeLists.txt. If you need to specify a compiler, do so by using the export CC=<path/to/compiler> and export CXX=<path/to/compiler> statements in cpp/build.sh.
    • It appears that everything works fine as long as the environment variables CC and CXX match the variables CMAKE_C_COMPILER and CMAKE_CXX_COMPILER.
    • NOTE : You may need to delete the file cpp/release/CMakeCache.txt for changes to take effect.
• If you get an error message when the file bindings.cpp is compiling, that originates from the pybind11 headers:
  • You are likely getting an error of the type

     error: address of overloaded function '<some_func>' does not match required type 'pybind11::overload_cast<some stuff>'
    

    and

    error: static_assert failed due to requirement 'detail::integral_constant<bool, false>::value' "pybind11::overload_cast<...> requires compiling in C++14 mode"
    

  • and you are likely using clang compiled for the C++-11 standard. (The compiler located in /usr/... on Mac is likely clang, even though it is called gcc)
  • To fix the issue:
    • Install gcc with homebrew.
    • Locate the compilers you’ve installed (which gcc-13 and which g++-13 should work if you installed gcc version 13.x.x)
    • Set the environment variables CC and CXX in cpp/build.sh to the path to these compilers by modifying the export statements. For example

      export CC=/opt/homebrew/bin/gcc-13
      export CXX=/opt/homebrew/bin/g++-13
      

  • NOTE: You may need to delete the file cpp/release/CMakeCache.txt for changes to take effect.
• If none of the above works, please feel free to leave an issue.

For Windows

Running cmake from the cpp directory should produce an MSVC solution file. Building this solution should generate the file KineticGas_r.cp<python-version>-win_amd64.pyd which will be displayed as a “python extension module”. Copy this file to the pykingas directory, and run pip install . from the top-level directory (where setup.py) is found.