*** Full-sky, Cosmic-variance only 1-sigma Error on the Local-form fNL ***
December 13, 2010: E.Komatsu
Refs: Komatsu & Spergel, PRD 63, 063002 (2001)

Here we provide a program for computing the the full-sky, cosmic-variance 
only 1-sigma error on the local-form fNL. This code reads in alpha_l(r)
and beta_l(r) calculated from the "compute_alphabeta" code, which is also 
available on Cosmology Routine Library. The error is given by

Error = 1/sqrt(F),

where 

F = sum_{2<=l1<=l2<=l3} B(l1,l2,l3)^2/[C(l1)C(l2)C(l3)Delta(l1,l2,l3)].

See Eq.(51) of Komatsu & Spergel (2001).

To calculate the errors, we need the angular power spectrum of CMB, C(l).
We provide the data for C(l), "wmap5baosn_max_likelihood_scalCls.dat," 
which was generated using CAMB code for the maximum likelihood parameters
given in Table I of Komatsu et al.(2008) [WMAP 5-year interpretation paper] 
with "WMAP5+BAO+SN". The input file for CAMB is also provided 
(wmap5baosn_max_likelihood_params.ini). 

- To compile and use the  program, edit Makefile and simply "./make"
- It will generate an executable called "compute_fNLerror"
- Run "./compute_fNLerror", which will generate a data file 
"lmax_fNLerror.txt", which contains lmax and 1-sigma errors.

For your convenience, the result of the calculation using the 
WMAP5+BAO+SN parameters is included as "wmap5baosn_max_likelihood_lmax=1500_fNLerror.txt".