CAMB: Transfer function at small k

[Steven Murray]

Hi everyone,

I am having an odd problem with my transfer function output using CAMB.

The Problem
At low-k I am getting an upturn in the transfer function, which happens at about [tex]k=10^{-4}[/tex]. Instead of having slope=0, I have a negative slope. This probably doesn't matter so much in many applications, but when I try to extrapolate this to integrate, it makes my extrapolation extremely bad.

My Setup
OS: OSX 10.7.5
CAMB version: This happens on the current version and also Oct2012 and Dec2011.
Makefile: The only modifications that I make to the makefile are to comment out the ifort compiler and to uncomment the gfortran compiler.
FFLAGS: -O3 -fopenmp -ffast-math -march=native -funroll-loops -mno-avx
USAGE: I just use the camb executable with an ini file to produce the function.
INI FILE: I'm not really sure what to report here. I think I leave everything as fairly normal - I mostly just change the cosmology (which doesn't affect the low-k rise).

My Question
Has anyone encountered this problem before? And if so, have they been able to fix it? At the moment I am post-processing the function and taking out the upturn but I would prefer not to have to!