ismoothing

This IDL facility provides an interface to F90 'smoothing' facility. It can be used to smooth a HEALPix map by an arbitrary circular 'beam' defined by its Legendre window function (or its FWHM if it is assumed Gaussian)

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

FORMAT

IDL> ISMOOTHING, map1_in, map2_out,[ beam_file=, binpath=, /double, fwhm_arcmin=, /help, iter_order=, keep_tmp_files=, lmax=, nlmax=, /nested, ordering=, plmfile=, regression=, /ring, simul_type=, /silent, theta_cut_deg=, tmpdir=, /won, w8file=, w8dir=]

QUALIFIERS

map1_in

required input: input map, can be a FITS file, or a memory array containing the map to smooth

map2_out

required output: output smoothed map, can be a FITS file, or a memory array

KEYWORDS

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/smoothing, then $HEALPIX/bin/smoothing
– 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 Full Width Half Maximum in arc-minutes default:0

/help

if set, prints extended help

iter_order=

order of iteration in the analysis default:0

/keep_tmp_files

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

lmax=, nlmax=

maximum multipole of smoothing default:determined by back-end routine (ie, smoothing)

/nested

if set, signals that *all* maps and mask read online are in NESTED scheme (does not apply to FITS file), /ring and Ordering

ordering=

either 'RING' or 'NESTED', ordering of online maps and masks, see /ring and /nested

plmfile=

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

regression=

0, 1 or 2, regress out best fit monopole and/or dipole before alm analysis default:0, analyze raw map

/ring

see /nested and Ordering above

simul_type=

1 or 2, analyze temperature only or temperature + polarization

/silent

if set, works silently

theta_cut_deg=

cut around the equatorial plane

tmpdir=

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

won=

if set to 0, no weighting applied, if set to 1, a ring-based quadrature weighting scheme is applied, if set to 2, a pixel-based quadrature weighting scheme is applied. default:1: apply ring-based weighting

w8file=

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

w8dir=

directory where the weights are to be found default:determined automatically by back-end routine

DESCRIPTION

ismoothing is an interface to 'smoothing' 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 ismoothing

idl

version 6.4 or more is necessary to run ismoothing.

smoothing

F90 facility called by ismoothing.

beam2bl

This IDL facility computes a transfer (or window) function b(l) (such as the ones required by ismoothing) for a given circular beam profile $b(\theta)$

ialteralm

IDL Interface to F90 alteralm

ianafast

IDL Interface to F90 anafast and C++ anafast_cxx

iprocess_mask

IDL Interface to F90 process_mask

isynfast

IDL Interface to F90 synfast

EXAMPLE:

whitenoise = randomn(seed, nside2npix(256))

ismoothing, whitenoise, rednoise, fwhm=120, /ring, simul=1,/silent

mollview, whitenoise,title='White noise'

mollview, rednoise, title='Smoothed white Noise'

will generate and plot a white noise map and its smoothed version