Cpp2Py is the Python-C++ interfacing tool of the TRIQS project, provided here as a standalone project.

Installation

To install Cpp2Py, follow the installation steps:

git clone  https://github.com/TRIQS/cpp2py.git cpp2py
mkdir build && cd build
cmake -DCMAKE_INSTALL_PREFIX=INSTALL_DIR ../cpp2py
make && make install

This installs the library in INSTALL_DIR. In order to make Cpp2Py available in your current environment you should run

source INSTALL_DIR/share/cpp2pyvars.sh

Example

Make sure that you have loaded Cpp2Py into your environment as instructed above. Created a C++ source file mymodule.hpp in a folder SRC:

///A wonderful little class
class myclass{
  int a, b;

  public:
    myclass(int a_, int b_) : a(a_), b(b_) {}

    ///getter for member a
    int get_a() const { return a;}
};

In the same folder, create a file CMakeLists.txt:

cmake_minimum_required(VERSION 3.0.2)
find_package(Cpp2Py REQUIRED)

add_cpp2py_module(mymodule)
target_compile_options(mymodule PRIVATE -std=c++17)
target_include_directories(mymodule PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})

Then, in the SRC folder, issue the command

c++2py mymodule.hpp

This creates a file mymodule_desc.py.

Exit the SRC folder and create a BUILD folder. Then, issue the following commands:

cd BUILD
cmake ../SRC
make

In the BUILD dir, you should see a mymodule.so file. You can now use your c++ class in Python:

import mymodule
A = mymodule.Myclass(4,5)
print(A.get_a())

By convention, c++ classes of the type my_little_class are converted in python classes of the type MyLittleClass.

License

Before you proceed, make sure you have read the LICENSE.txt file.

Enjoy!

The TRIQS team