## [memory] pdos calculations and eigenvalue array

There is an unnecessary memory usage in PDOS calculations when using very high PDOS kpoints.

The PDOS calculations only *ever* require 1 array of eigenvalues corresponding to the number of states.
This is because we don't store the values subsequently.

A simple fix would be to have a local array in each of the routines `pdos*.F`

with this and omit all use of `eo`

in `pdos.F`

.

Additionally it might be nice to have an additional file `siesta.PDOS.EIG`

which contains the full eigenvalue spectrum? Currently `.EIG`

is a bit bad to use for DOS since it contains the SCF eigenvalues which are typically not having the same precision as what is required for accurate DOS calculations. In master we have `kpoint_dos.F90`

which is the *default* for LDOS+PDOS. So perhaps we should have additional files: `siesta.[PL]DOS.EIG`

for the explicit calculations.

Note, the same won't apply to LDOS since that requires the full set of eigenvalues, on the other hand `eo`

does not contain SCF eigenvalues.