C Installation Instructions

Requirements

Before compiling the C API of qiskit-fermions you need to compile Qiskit’s C API. You may do this in any location but to get your started quickly, these steps can get you started quickly:

$ cd path/to/qiskit-fermions
$ git clone git@github.com:Qiskit/qiskit.git build/qiskit
$ cd build/qiskit
$ make c

Hint

On Windows only, you will need to copy additional library files:

Windows

$ cp target/release/qiskit_cext.dll dist/c/lib/qiskit_cext.dll
$ cp target/release/qiskit_cext.dll.lib dist/c/lib/qiskit_cext.dll.lib
$ cp target/release/qiskit_cext.dll.lib dist/c/lib/qiskit.dll.lib

At this point, you should have successfully compiled Qiskit’s C API. You can now move on to the steps of compiling qiskit-fermions C API below.

If you want to test your installation, you will need to install the following dependencies:

• CMake

Steps

1. Ensure that you are in the right directory:

   $ cd path/to/qiskit-fermions
   

2. Configure your shell environment with the locations of your compiled Qiskit C API library and include directory.

   Hint

   Here we assume the build/qiskit path from the quickstart example at the top, you need to adjust the paths according to your setup.

   UNIX

   $ export QISKIT_LIB=$(find $(pwd)/build/qiskit/dist/c/lib -name "libqiskit.*")
   $ export QISKIT_INCLUDE=$(pwd)/build/qiskit/dist/c/include
   

   Windows

   $ export QISKIT_LIB=$(find $(pwd)/build/qiskit/dist/c/lib -name "qiskit_cext.dll.lib")
   $ export QISKIT_INCLUDE=$(pwd)/build/qiskit/dist/c/include
   

3. Compile the C API of qiskit-fermions:

   $ make cext
   

3. (optional) Verify the installation by running the C unittests:

   $ make testc
   

You should now find these relevant files:

• dist/c/lib/libqiskit_fermions.so (the suffix can vary depending on your OS)

• dist/c/include/qiskit_fermions.h