alm_i2t
This IDL function turns an indexed list of alm (as generated by
fits2alm) into a tabular (real or complex) a(l,m) array for easier manipulation
Location in HEALPix directory tree: src/idl/misc/alm_i2t.pro
FORMAT
QUALIFIERS
-
Index
- Integer vector of size ni containing the index i of the
of alm coefficients, related to {l,m} by
i = l2 + l + m + 1
-
Alm_vec
- Array of alm coefficients, with dimension (ni, nalm [,nsig])
where
ni = number of i indices
nalm = 2 for real and imaginary parts of alm coefficients or
4 for above plus corresponding error values
nsig = number of signals (usually 1 for any of T E B
or 3 for T,E,B together)
KEYWORDS
-
/COMPLEX
- if set, the output array is complex with dimensions
(lmax+1, mmax+1, [nalm/2 , nsig]),
otherwise, the array is real with dimensions
(lmax+1, mmax+1, nalm [, nsig]).
lmax and mmax are determined from input Index values, unless set otherwise
by user.
-
/HELP
- if set, prints out the help header and exits
-
LMAX=
- lmax to be used in output array, regardless of
value found in input index
-
MMAX=
- mmax to be used in output array, regardless of
value found in input index
DESCRIPTION
alm_i2t returns a real or complex array, containing the alm with
and
. The negative m are
therefore ignored.
RELATED ROUTINES
This section lists the routines related to alm_i2t
-
idl
- version 6.4 or more is necessary to run alm_i2t.
-
alm_t2i
- turns tabular alm's such as those generated by
alm_i2t into indexed lists than can written to FITS files with
alm2fits
-
alm2fits, fits2alm
- routines to read and write alm indexed lists from and to FITS files.
EXAMPLE:
The example above reads 2 sets of alm from FITS files, puts the alm's with (l,m)
in tabular arrays, and then make a weighted sum of the alm's. The
resulting alm or put back into a indexed list in order to be written to FITS.
Version 3.30, 2015-10-08