# 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`

.