alm_t2i
This IDL facility turns a tabular (real or complex) a(l,m) array into an
indexed list of alm that can be written into a FITS file with alm2fits
Location in HEALPix directory tree: src/idl/misc/alm_t2i.pro
FORMAT
QUALIFIERS

Alm_table
 Input real or complex array, containing all the a^{s}_{lm} for l
in [0,] and m in [0,]
(and s in [0,] if applicable)
if REAL it has 3 (or 4) dimensions,
if COMPLEX is has 2 (or 3) dimensions

Index
 Output integer vector of size ni containing the index i of the
of a_{lm} coefficients, related to {l,m} by
i = l^{2} + l + m + 1

Alm_vec
 Output array of a_{lm} coefficients, with dimension (ni, 2 [,])
where
ni = number of i indices
2 for real and imaginary parts of alm coefficients
= number of signals (usually 1 for any of T E B
or 3 for T,E,B together)
KEYWORDS

/HELP
 if set, prints out the help header and exits

/MFIRST
 if set, the input array is a(m,l) instead of a(l,m)
DESCRIPTION
alm_t2i turns a real or complex tabular array of a(l,m) (or a(m,l) is MFIRST is
set) into a real list of a_{lm} (with the real and imaginary parts separated)
and its index i=l^{2}+l+m+1. The unphysical m>l elements of the input
table are dropped from the output list.
RELATED ROUTINES
This section lists the routines related to alm_t2i

idl
 version 6.4 or more is necessary to run alm_t2i.

alm_i2t
 this function is complementary to
alm_t2i and
turns an indexed list of alm (as generated by
fits2alm) into a tabular (real or complex) a(l,m) array
for easier manipulation

alm2fits, fits2alm
 routines to read and write a_{lm} indexed lists from and to FITS files.
EXAMPLE:
See alm_i2t example
Version 3.31, 20170106