NAME

   fnl_mapmaking

   Generating non-Gaussian simulations of the Cosmic Microwave
   Background (CMB)

DESCRIPTION

   The purpose of this algorithm is to simulate temperature and
   polarization realizations of the CMB that contain non-Gaussianity
   of local type in the Healpix pixelization scheme. For a full
   description, see https://arxiv.org/abs/0909.0009. The code is
   written in Fortran and hybrid MPI/OpenMP parallelized for an
   efficient execution on computer clusters.

INSTALLATION

   Prerequisites: - Healpix
                  - Intel Math Kernel Library
                  - CFITSIO library

   Prior to compilation, please edit the 'Makefile' to reflect
   your MPI compiler wrapper. The path to all relevant components
   of the Intel MKL, including lapack95 and blas95, should be
   adapted. Additionally, the Healpix and CFITSIO libraries must
   be available for linking.

USAGE

   The algorithm reads keyword - keyvalue pairs from a namelist in
   the configuration file located at './config/input.cfg'. Here,
   the user is asked to specify

   NR_SIMS:
      The number of simulations to generate.

   NR_SHELLS:
      The number of radial nodes used in the line of sight
	  integration of curvature perturbations.

   NSIDE:
      Resolution parameter of Healpix maps.

   LMAX:
      Maximum multipole moment of the simulated maps.

   INCLUDE_POL:
      Boolean flag indicating if simulations should also include
	  polarization.

   DIR_IN_W8RING:
      Directory of the Healpix pixel weights, typically
      $HEALPIX/data. Only the directory should be specified, the
      file name itself will be appended according to the Healpix
      naming convention.

   FILE_PREFIX_COSMO:
      Abbreviation describing the cosmology assumed in the
	  simulation.

   FILE_PREFIX_NG_AUX:
      Directory containing all auxiliary input files specified 
	  below.

   FILE_IN_WEIGHTS:
      File containing the numerical quadrature weights used in
	  the line of sight integration of curvature perturbations.
	  The string given by 'NR_SHELLS.fits' will be automatically
	  appended.

   FILE_IN_WEIGHTS_MU:
      File prefix containing the numerical quadrature weights that
	  can be used to compute mu perturbations. The string given
	  by 'NR_SHELLS.fits' will be automatically appended.

   FILE_IN_COV:
      File prefix for the covariance matrices of primordial 
	  curvature perturbations. The string given by
	  'NR_SHELLS.fits' will be automatically appended.

   FILE_IN_COV_MU:
      File prefix for the covariance matrices of mu perturbations. 
	  The string given by 'NR_SHELLS.fits' will be automatically 
	  appended.

   FILE_OUT_SIGNAL_L:
      File naming convention for output files containing the linear
	  (Gaussian) component of the CMB realization. The
	  placeholder '%MCNUMBER%' will be replaced by the simulation
	  number.

   FILE_OUT_SIGNAL_NL:
      File naming convention for output files containing the
	  non-Gaussian CMB map of local type. The placeholder
	  '%MCNUMBER%' will be replaced by the current simulation 
	  number.

   FILE_OUT_SIGNAL_NNL:
      File naming convention for output files containing the
	  CMB maps for the cubic term. The placeholder '%MCNUMBER%'
	  will be replaced by the current simulation number.

   FILE_OUT_SIGNAL_MU:
      File naming convention for output files containing maps of
	  mu perturbations. The placeholder '%MCNUMBER%' will be
	  replaced by the current simulation number.

RESTRICTIONS

   Example files to compute non-Gaussian maps for Planck cosmology
   are provided in the 'data' directory.

   We do not provide inputs to generate mu perturbations!
   Corresponding code sections have to be commented out in the
   source code prior to compilation.

   Please cite https://arxiv.org/abs/0909.0009 if you make use of
   this algorithm in scientific publications.