Installation

The following instructions for installing QSym² from source are specific to Linux operating systems. On Microsoft Windows platforms, Windows Subsystem for Linux is recommended.

There are two main ways of installing QSym²:

• as a binary named qsym2 providing the command-line interface, or
• as a Python library named qsym2 providing the exposed Python bindings.

Both methods can be configured via Rust features.

Binary compilation

The following instructions assume that the full feature is to be installed on a Linux operating system to make available the qsym2 binary.

1. Install the basic dependencies by running the following commands (sudo privileges required):

   Debian/UbuntuRocky/Fedora/RHEL

   Bash

   sudo apt-get update
   sudo apt-get install curl git libssl-dev pkg-config
   

   Bash

   sudo dnf update
   sudo dnf install curl git-all openssl-devel pkgconfig
   

2. Install the Rust compiler by running the command below and following the on-screen instructions:

   Bash

   curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
   

   The default configurations should suffice in most cases. Ensure that the current shell is restarted or the command source "$HOME/.cargo/env" is run upon installation completion so that the Rust compiler and the cargo package manager can be found.

3. Install the feature-specific dependencies by running the following command (sudo privileges required):

   Debian/UbuntuRocky/Fedora/RHEL

   Bash

   sudo apt-get install build-essential gfortran cmake
   

   Bash

   sudo dnf install make automake gcc gcc-c++ kernel-devel gfortran cmake
   

4. Obtain the source code of QSym² either via git:

   Bash

   git clone https://gitlab.com/bangconghuynh/qsym2.git
   

   or by downloading a compressed tarball release and extracting it.

5. Inside the source code directory, install QSym² by running the following command:

   Bash

   cargo install --features full --path .
   

   which will compile and install the qsym2 binary into $HOME/.cargo/bin to allow for system-wide availability.

   Note that the --features option in the command above specifies that the full feature is to be installed. This option accepts a comma-separated list of features listed in the Rust features section and can be modified to select other features to be installed as appropriate.

   It is possible to install the qsym2 binary into a different path by running

   Bash

   cargo install --features full --path . --root custom/install/path/for/qsym2
   

   instead. The custom path /custom/install/path/for/qsym2 must then be added to the $PATH environment variable to make qsym2 discoverable by the operating system.

Python-library compilation

The following instructions assume that the openblas-static, integrals, and python features are to be compiled on a Linux operating system and then installed as a Python library inside a conda environment. These features are specified in the pyproject.toml file.

1. Follow steps 1 to 4 under the Binary compilation section above to install the required prerequisites.
2. Make sure that the Anaconda package manager is available on your system. Instructions for installing Anaconda on a Linux system can be found here.
3. Create a new conda environment named qsym2-python (or a different name of your choice) running Python 3.13 (or a different version of your choice):
   Bash

   conda create -n qsym2-python python="3.13"
   

   and then activate this environment:
   Bash

   conda activate qsym2-python
   

4. From inside the source code directory, execute

   Bash

   pip install .
   

   This command calls pip which automatically acquires the build tool maturin to compile and install QSym² as a Python library into the qsym2-python conda environment. This library has the openblas-static, integrals, and python features enabled due to the specification in the pyproject.toml file.

   The Python library qsym2 can now be imported by any Python scripts running inside the qsym2-python conda environment.