ianafast


This IDL facility provides an interface to 'anafast' F90 and 'anafast_cxx' C++ facilities. It can be used to produce the Spherical Harmonics coefficients (alm of a HEALPix map (or pair of maps) and/or the resulting auto (or cross) power spectra C(l).

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


FORMAT

IDL> IANAFAST, map1_in[, cl_out, alm1_out=, alm2_out=, binpath=, cxx=, double=, help=, healpix_data=, iter_order=, keep_tmp_files=, map2_in=, maskfile=, nested=, nlmax=, nmmax=, ordering=, plmfile=, polarisation=, regression=, ring=, show_cl=, simul_type=, silent=, theta_cut_deg=, tmpdir=, weighted=, won=, w8file=, w8dir=]


QUALIFIERS

map1_in
required input: 1st input map, can be a FITS file, or a memory array containing the map to analyze
cl_out
optional output: auto or cross power spectrum C(l), can be a FITS file or a memory array


KEYWORDS

alm1_out=
output alm of 1st map, must be a FITS file default:alm not kept

alm2_out=
output alm of 2nd map (if any, must be a FITS file) default:alm not kept

binpath=
full path to back-end routine default:$HEXE/anafast, then $HEALPIX/bin/anafast or $HEALPIX/src/cxx/$HEALPIX_TARGET/bin/anafast_cxx, then $HEALPIX/src/cxx/generic_gcc/bin/anafast_cxx if cxx is set
- 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

/cxx
if set, the C++ back-end anafast_cxx is invoked instead of F90 anafast, AND the parameter file is written accordingly

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

/help
if set, prints extended help

healpix_data=
directory with Healpix precomputed files (only for C++ back_end when weighted=1) default:$HEALPIX/data

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

map2_in=
2nd input map (FITS file or array), if provided, Cl_out will contain the cross power spectra of the 2 maps default:no 2nd map

maskfile=
pixel mask (FITS file or array) default:no mask

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

nlmax=
maximum multipole of analysis, *required* for C++ anafast_cxx, optional for F90 anafast

nmmax=
maximum degree m, only valid for C++ anafast_cxx default:nlmax

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

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

/polarisation
if set analyze temperature + polarization (same as simul_type = 2)

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

/show_cl
if set, and cl_out is defined, the produced $l(l+1)C(l)/2\pi$ will be plotted

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)

/weighted
same as won default:apply weighting

/won
if set, a weighting scheme is used to improve the quadrature default:apply 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

ianafast is an interface to 'anafast' F90 and 'anafast_cxx' C++ facilities. 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 ianafast

idl
version 6.4 or more is necessary to run ianafast.
anafast
F90 facility called by ianafast.
anafast_cxx
C++ called by ianafast.
ialteralm
IDL Interface to F90 alteralm
iprocess_mask
IDL Interface to F90 process_mask
ismoothing
IDL Interface to F90 smoothing
isynfast
IDL Interface to F90 synfast


EXAMPLE:

whitenoise = randomn(seed, nside2npix(256))
ianafast, whitenoise, cl, /ring, /silent
plot, cl[*,0]
will plot the power spectrum of a white noise map

Version 3.31, 2017-01-06