This IDL facility provides an interface to F90 'synfast' facility. It can be used to generate sky maps and/or a_lm from power spectra (C(l)), synthesize maps from a_lm or simulate maps from C(l) and constraining a_lm.

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(l), 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: map synthetised from the power spectrum or from constraining alm

KEYWORDS

alm_in=: optional input (constraining) alm default:no alm
alm_out=: contains on output the effective alm
/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
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 binpathes 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* $N_{\rm side}$
nside=, nsmax=: Healpix resolution parameter $N_{\rm side}$
plmfile=: FITS file containing precomputed Spherical Harmonics 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 6.1 or more is necessary to run isynfast.
synfast: F90 facility called by isynfast.
ismoothing: IDL Interface to F90 smoothing
ianafast: IDL Interface to F90 anafast and C++ anafast_cxx

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 constistent with WMAP-1yr best fit power spectrum and observed with a circular gaussian 30 arcmin beam.

Eric Hivon 2010-06-18

Contact:

Site Manager:
Webmaster:
CL 03-2650

This IDL facility provides an interface to F90 'synfast' facility. It can be used to generate sky maps and/or alm from power spectra (C(l)), synthesize maps from alm or simulate maps from C(l) and constraining alm.