# Inteqp code overview

This code takes the eqp_co.dat file from Sigma and interpolates it from the coarse to the fine grid using wavefunction projections (to resolve band crossings) and linear interpolation in the Brillouin zone.

## Summary of input and output files

### Required input files:

• inteqp.inp : Input parameters.

• WFN_fi : Wavefunctions in unshifted fine grid.

• WFN_co : Wavefunctions on coarse grid.

• eqp_co.dat : A list of quasiparticle energy corrections for the bands in WFN_co.

• WFNq_fi : Wavefunctions in shifted fine grid (used for valence bands if use_velocity is selected)

### Auxiliary Files

The files are output files from previous runs - used as input to speed up calculation.

• dtmat : Transformation matrices, dcc/dvv use for interpolation between coarse and fine grid. This file must be consistent with your bsedmat and bsexmat files and corresponding coarse and fine wavefunctions. NOTE: the file format for dtmat was changed in BerkeleyGW 1.1.0 (r5961)

### Output Files

• bandstructure.dat : The GW bandstructure on the fine grid.

• eqp.dat : Quasiparticle energy corrections for the bands in WFN_fi.

• eqp_q.dat : Quasiparticle energy corrections for the bands in WFNq_fi (if use_velocity).

• dvmat_norm.dat : The norms of the dvv overlap matrices between the valence band k on the fine grid and the closest k-point on the coarse grid.

• dcmat_norm.dat : The norms of the dcc overlap matrices between the conduction band k on the fine grid and the closest k-point on the coarse grid