$EWALD group       (relevant for all-EFP runs with PBC)
 
   This group controls evaluation of the electrostatic
energy of EFP calculations by means of the Ewald sum
formulae.  This gives a more accurate evaluation of these
long range interactions than the minimum image convention,
which sums only up to a distance of one box, centered on
each particle.  Ewald sum formulae are not used for the
other, shorter range interactions in the EFP model, such as
exchange repulsion and polarization, which are always
evaluated by the minimum image convention.  This group is
relevant if and only if a periodic box is defined in the
$EFRAG input group.
 
IFEWLD = a flag to activate Ewald sums for electrostatics
         The default is .FALSE.
 
LEVEL  = 1 means Ewald sum charge-charge interactions only,
           which is the default if IFEWLD is turned on.
       = 2 charge-charge, charge-dipole, dipole-dipole
       = 3 charge-charge, charge-dipole, dipole-dipole, and
           charge-quadrupole terms should be Ewald summed.
 
TNFOIL = a flag to select tin foil boundary conditions,
         which uses a metallic continuum past the cutoffs,
         instead of a vacuum.  The default is .TRUE.
 
BETA   = parameter for the direct summation, in 1/Bohr.
         It should be 1.7/cutoff.  Cutoffs are specified
         in $EFRAG, with the periodic box sizes, use a
         cutoff in units Angstrom in this formula, as the
         value 1.7 includes the conversion factor.
         The default=0.2
 
KMAX   = number of reciprocal vectors in each direction.
         This should be kmax >= 3.2L/cutoff, where the
         radial cutoff, and box side L are both given in
         your $EFRAG.  The default=10