## E/B separation paper extra material

See the Harmonic E/B separation example maps.
Also powerpoint file for Paris talk on E/B separation (2004).

## CMB polarization codes

### Spin-weight spherical harmonics

There is an F90 module for computing spin-weight
spherical harmonics. There are thread-safe routines, routines for computing
arrays of harmonics, and routines for computing inner products of spherical
harmonics over azimuthal cuts. Most basic usage is
lambda = SH_lambdaslm(s,l,m,x)

where sYlm = lambda*e^{i*m*phi}, s is the spin, and x is cos(theta). Sign
conventions and documentation in astro-ph/0106536.
### Large scale B-mode extraction for asymmetric cuts

In astro-ph/0305545
I presented a method for extracting large scale pure B modes from general
cuts (without smoothing). This download has routines
for computing coupling matrices from the a_lm of a sky cut, and a sample program
to construct the projection matrix into the well supported nearly-pure B
modes. Requires BLAS and LAPACK, and (for larger lmax), a 64-bit compiler.
Includes Matric_utils module which provides a conventient wrapper around some
commonly used BLAS and LAPACK routines.
### Exact E/B separation for azimuthal cuts

In astro-ph/0106536
we explain a harmonic method for separating E and B polarization modes on
an incomplete sky.

You can download a simple demonstration program.
This includes SpinHarmonics.f90, a module for computing spin-weight harmonics
and their inner products over an azimuthally symmetric patch of sky.

The sample program itself (dopolar.f90) is very basic and extracts the
E or B modes from a file of cut sky a_lms. It reads in a file of parameters
(supplied params.ini), which includes a FITS file of the assumed power spectrum.
The output is the 'number of sigmas' away from zero, assuming the given isotropic
noise. The program is not designed to be realistically useful, but may make
a useful starting point.

The program processes a file of a_lms in FITS
format, as produced by HEALPIX.
You will need FITSIO, HEALPIX and LAPACK
installed to compile. You will need to edit the supplied Makefile with the
correct location of these files.

The input power spectrum FITS file can be produced by CMBFAST or CAMB.

Antony Lewis May 2003.