Hi Nichols,
The grid used for the calculation of the two center integrals
(calculated in matel.f) is fixed to 2000Ry,
while the one used for the three center integrals is set by the user
using MeshCutoff. They are
completely independent.
My question is about SIESTA and how the MeshCutoff is used. The
charge density
is on a grid and Fourier contributions of the *density* up to
E_cutoff are represented.
This is equal to four times the E_cutoff used in the PW codes to
represent the
*basis* functions (i.e. planewaves).
In Siesta the density is written as a combination of pseudo atomic
orbitals (squared!) which are projected
into that grid, so i think the comparison is misleading. In the main
Siesta paper you have
a comparison which I think is more fair.
Regards,
Eduardo
