Whether to calculate dipole matrix elements, to be written in vmtxel. This should be done when calculating WFN_fi for Bethe-Salpeter calculations with light polarization in a finite direction. In that case, a shifted grid WFNq_fi cannot be calculated, but we can instead use matrix elements of $r$ in a more exact scheme. In absorption.inp, set read_vmtxel and use_momentum. Specify the number of conduction and valence bands you will use in BSE here with BerkeleyGW_VmtxelNumCondBands and BerkeleyGW_VmtxelNumValBands.