Parameters read by mult_alm:

infile (string):
  input file containing the a_lm

outfile (string):
  output file name for the calculated a_lm

fwhm_arcmin_in (real, default=0):
  FWHM (in arcmin) of a Gaussian beam, which will be _removed_ from the
  input a_lm

fwhm_arcmin_out (real, default=0):
  FWHM (in arcmin) of a Gaussian beam, which will be used to smoothe the
  output a_lm

nside_pixwin_in (integer, default=0):
  If this is different from 0, the corresponding pixel window function
  will be _removed_ from the input a_lm

nside_pixwin_out (integer, default=0):
  If this is different from 0, the corresponding pixel window function
  will be applied to the output a_lm

if ((nside_pixwin_in>0)||(nside_pixwin_out>0))
  healpix_data (string):
    directory containing the Healpix data files
endif

double_precision (bool, default=false):
  if false, the a_lm are read/written in single precision,
  otherwise in double precision.