# Typical workflow

In order to to compute GW quasiparticle energies and optical absorption spectra including excitonic effects with BerkeleyGW, one is required to run the following steps:

• A mean-field program of their choice, such as Quantum ESPRESSO, PARATEC, Abinit, PARSEC, OCTOPUS, and SIESTA, and generate a set of files;
• The epsilon executable from the BerkeleyGW package, to generate the dielectric matrix;
• The sigma executable from the BerkeleyGW package, to compute the GW quasiparticle energies;
• The kernel executable from the BerkeleyGW package, to compute the BSE kernel matrix elements on a coarse k-point grid; and
• The absorption executable from the BerkeleyGW package, to interpolate the BSE kernel matrix elements to a fine k-point grid, diagonalize the BSE Hamiltonian, and compute the optical absorption spectrum.

A typical workflow for this set of calculations with BerkeleyGW, including input and output files, is summarized in the diagram below:

In addition, there is a package to automate these workflows and simply calculations using the high-level Python language, BGWpy.