README.rst

koopmans

For performing Koopmans spectral functional calculations with Quantum ESPRESSO

Directories

This repository contains...

bin/ executables (N.B. this directory does not need to be added to $PATH)

docs/ documentation (see https://koopmans-functionals.org/)

src/ source code

quantum_espresso/ modified versions of Quantum ESPRESSO that contain implementations of the Koopmans functionals

pseudos/ pseudopotentials

requirements/ python dependencies

tests/ test suite

tutorials/ tutorials

Installation

Quick installation

For a quick installation one can simply run make; sudo make install

Detailed installation

Setting up a virtual environment

You are encouraged (but it is not necessary) to first create and activate a virtual environment as follows:

sudo apt-get install python3-pip
pip3 install virtualenv
virtualenv ~/venvs/koopmans
source ~/venvs/koopmans/bin/activate

Note that koopmans requires python v3.7 or later. If your computer's version of python3 corresponds to an earlier version, install python v3.7 or later, and then direct virtualenv to create the virtual environment using that specific installation of python via

virtualenv ~/venvs/koopmans -p /usr/bin/python3.x

Fetching the submodules

Now, ensure you have downloaded the various git submodules. To do so, run make submodules, or equivalently

git submodule init
git submodule update

Compiling Quantum ESPRESSO

Then you need to compile the copies of Quantum ESPRESSO. To do this, run

make espresso MPIF90=<mpif90>

where <mpif90> should be replaced by the name of your chosen MPI Fortran90 compiler e.g. MPIF90=mpiifort. The code should automatically detect and link the requisite libraries. (If this fails you may need to manually compile the two versions of Quantum ESPRESSO contained in the quantum_espresso/ directory.)

Adding Quantum ESPRESSO to your path

To add all of the Quantum ESPRESSO binaries to your path, run

sudo make install

By default this will copy the Quantum ESPRESSO binaries to /usr/local/bin. This requires sudo privileges. If you do not have sudo privileges, you can either (a) install the codes in a different location by running make install PREFIX=/path/to/bin/ (substitute /path/to/bin/ with any directory of your choosing that is on your path) or (b) append bin/ from the current directory to your path.

Installing the workflow manager

Finally, install the python workflow manager, either via make workflow, or

python3 -m pip install --upgrade pip
python3 -m pip install -e .

Running

Calculations are run with the command

koopmans <seed>.json

where <seed>.json is the koopmans input file. For more details, refer to the online documentation.

Parallelism

In order to run the code in parallel, define the environment variables PARA_PREFIX and PARA_POSTFIX. These are defined in the same way as in Quantum ESPRESSO, e.g.

export PARA_PREFIX="srun"
export PARA_POSTFIX="-npool 4"

Pseudopotentials

Currently, Koopmans functionals only works with norm-conserving pseudopotentials. We suggest you use optimized norm-conserving Vanderbilt pseudopotentials, such as

• the SG15 library
• the Pseudo Dojo library

For convenience, koopmans already ships with both of these pseudopotential libraries and you can simply select the one you want to use using the pseudo_library keyword.

If you prefer to use your own pseudopotentials, add them to src/koopmans/pseudopotentials/<my_pseudos>/<functional>, where <my_pseudos> is a name of your choosing and <functional> is the functional used to generate your pseudopotentials. You can then direct koopmans to use these pseudopotentials by setting the keywords pseudo_library and base_functional to <my_pseudos> and <functional> respectively.

Alternatively, you can direct the code to always use your personal pseudopotentials directory by defining the variable

export ESPRESSO_PSEUDO="/path/to/pseudopotential/folder/"

Contact

Written and maintained by Edward Linscott, Riccardo De Gennaro, and Nicola Colonna (2020-)

For help and feedback email [email protected]