isynfast

This IDL facility provides an interface to F90 'synfast' facility. It can be used to generate sky maps and/or $a_{\ell m}$ from power spectra ($C(\ell)$), synthesize maps from $a_{\ell m}$ or simulate maps from $C(\ell)$ and constraining $a_{\ell m}$.

Location in HEALPix directory tree: src/idl/interfaces/isynfast.pro 

FORMAT

IDL> ISYNFAST, cl_in[, map_out, alm_in=, alm_out=, apply_windows=, beam_file=, binpath=, double=, fwhm_arcmin=, help=, iseed=, keep_tmp_files=, lmax=, nlmax=, nside=, nsmax=, plmfile=, simul_type=, silent=, tmpdir=, windowfile=, winfiledir=]

QUALIFIERS

cl_in

input power spectrum, can be a FITS file, or a memory array containing the $C(\ell)$, used to generate a map or a set of gaussian alm
If empty quotes (”) or a zero (0) are provided, it will be interpreted as "No input C(l)", in which case some input alm's (alm_in) are required.

map_out

optional output: RING ordered map synthetised from the power spectrum or from constraining alm

KEYWORDS

alm_in=

optional input (constraining) alm (must be a FITS file) default:no alm

alm_out=

contains on output the effective alm (must be a FITS file)

/apply_windows

if set, beam and pixel windows are applied to input alm_in (if any)

beam_file=

beam window function, either a FITS file or an array (see ”Beam window function files” section in the HEALPix Fortran Facilities document)

binpath=

full path to back-end routine default:$HEXE/synfast, then $HEALPIX/bin/synfast
– a binpath starting with / (or $\backslash$),   or $ is interpreted as absolute
– a binpath starting with ./ is interpreted as relative to current directory
– all other binpaths are relative to $HEALPIX

/double

if set, I/O is done in double precision default:single precision I/O

fwhm_arcmin=

gaussian beam FWHM in arcmin default:0

/help

if set, prints extended help

iseed=

integer seed of radom sequence default:0

/keep_tmp_files

if set, temporary files are not discarded at the end of the run

lmax=, nlmax=

maximum multipole simulation default:2* N_side

nside=, nsmax=

Healpix resolution parameter N_side

plmfile=

FITS file containing precomputed Spherical Harmonics (deprecated) default:no file

simul_type=

1) Temperature only
2) Temperature + polarisation
3) Temperature + 1st derivatives
4) Temperature + 1st & 2nd derivatives
5) T+P + 1st derivatives
6) T+P + 1st & 2nd derivates default:2: T+P

/silent

if set, works silently

tmpdir=

directory in which are written temporary files default:IDL_TMPDIR (see IDL documentation)

windowfile=

FITS file containing pixel window default:determined automatically by back-end routine. Do not set this keyword unless you really know what you are doing

winfiledir=

directory where the pixel windows are to be found default:determined automatically by back-end routine. Do not set this keyword unless you really know what you are doing

DESCRIPTION

isynfast is an interface to F90 'synfast' F90 facility. It requires some disk space on which to write the parameter file and the other temporary files. Most data can be provided/generated as an external FITS file, or as a memory array.

RELATED ROUTINES

This section lists the routines related to isynfast

idl

version 6.4 or more is necessary to run isynfast.

synfast

F90 facility called by isynfast.

ialteralm

IDL Interface to F90 alteralm

ianafast

IDL Interface to F90 anafast and C++ anafast_cxx

iprocess_mask

IDL Interface to F90 process_mask

ismoothing

IDL Interface to F90 smoothing

EXAMPLE:

isynfast, '$HEALPIX/test/cl.fits', map, fwhm=30, nside=256, /silent

mollview, map, 1, title='I'

mollview, map, 2, title='Q'

will synthetize and plot I and Q maps consistent with WMAP-1yr best fit power spectrum and observed with a circular gaussian 30 arcmin beam.