fits2alms*

This routine reads $a_{\ell m}$ values from a binary FITS file. Each FITS file extension is supposed to contain one integer column with $index=\ell^2+\ell+m+1$ and 2 or 4 single (or double) precision columns with real/imaginary $a_{\ell m}$ values and real/imaginary standard deviation. One can read temperature $a_{\ell m}$ or temperature and polarisation, $a^T_{\ell m}$, $a^E_{\ell m}$ and $a^B_{\ell m}$.

Location in HEALPix directory tree: src/f90/mod/fitstools.F90 

FORMAT

call fits2alms*( filename, nalms, alms, ncl, header, nlheader, next )

ARGUMENTS

name & dimensionality	kind	in/out	description
filename(LEN=filenamelen)	CHR	IN	filename of the FITS-file to read the $a_{\ell m}$ from.
nalms	I4B	IN	number of $a_{\ell m}$ to read.
ncl	I4B	IN	number of columns to read in the FITS file. If an standard deviation is to be read, this number is 5, otherwise it is 3.
next	I4B	IN	the number of extensions to read. 1 for temperature only, 3 for temperature and polarisation.

alms(1:nalms,1:(ncl+1),1:next)	SP/ DP	OUT	the $a_{\ell m}$ to read from the file. alms(i,1,j) and alms(i,2,j) contain the $\ell$ and $m$ values for the ith $a_{\ell m}$ (j=1,2,3 for (T,E,B)). alms(i,3,j) and alms(i,4,j) contain the real and imaginary value of the ith $a_{\ell m}$. Finally, the standard deviation for the ith $a_{\ell m}$ is contained in alms(i,5,j) (real) and alms(i,6,j) (imaginary).
nlheader	I4B	IN	number of header lines to read from the file.
header(LEN=80) (1:nlheader, 1:next)	CHR	OUT	the header(s) read from the FITS-file.

EXAMPLE:

call fits2alms ('alms.fits', 65*66/2, alms, 3, header, 80, 3)

Reads a FITS file with the $a_{\ell m}^T$, $a_{\ell m}^E$ and $a_{\ell m}^B$ values read into alms(1:65*66/2,1:4,1:3). The last index specifies (T,E,B). The second index gives l, m, real( $a_{\ell m}$ ), imaginary( $a_{\ell m}$ ) for each of the $a_{\ell m}$. The number 65*66/2 is the number of $a_{\ell m}$ values up to an $\ell$ value of 64. 80 lines is read from the header in each extension and returned in header(1:80,1:3).

MODULES & ROUTINES

This section lists the modules and routines used by fits2alms*.

read_alms

routine called by fits2alms* for each extension.

fitstools

module, containing:

printerror

routine for printing FITS error messages.

cfitsio

library for FITS file handling.

RELATED ROUTINES

This section lists the routines related to fits2alms*

alms2fits, dump_alms

routines to store $a_{\ell m}$ in a FITS-file

read_conbintab

has the same function as fits2alms* but with parameters passed differently.

number_of_alms, getsize_fits

can be used to find out the number of $a_{\ell m}$ available in the file.