I am new to CAMB and as a test I am just trying to reproduce the WMAP3 results for lcdm+tens model using the parameters given here.
When I plot the totCls.dat file output by CAMB along with the one given on the LAMBDA website I see a large difference around l<100. Can anyone explain whether this is normal or suggest a fix?
I have changed both k0_scalar and k0_tensor to 0.002 in power_tilt.f90. I am taking nT = -r / 8.
Here is my params.ini file:
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#Parameters for CAMB #output_root is prefixed to output file names output_root = test_lcdm_tens #What to do get_scalar_cls = T get_vector_cls = F get_tensor_cls = T get_transfer = F #if do_lensing then scalar_output_file contains additional columns of l4 Cl&#123;pp} and l3 Cl&#123;pT} #where p is the projected potential. Output lensed CMB Cls (without tensors) are in lensed_output_file below. do_lensing = F # 0: linear, 1: non-linear matter power (HALOFIT), 2: non-linear CMB lensing (HALOFIT) do_nonlinear = 0 #Maximum multipole and k*eta. # Note that Cls near lmax are inaccurate (about 5%), go to 50 more than you need # Lensed power spectra are computed to lmax_scalar−250 where accurate at %-level # For high accuracy lensed spectra set lmax_scalar = (l you need) + 500 # To get accurate lensed BB need to have lmax_scalar>2000, k_eta_max_scalar > 10000 # Otherwise k_eta_max_scalar=2*lmax_scalar usually suffices lmax_scalar = 2000 k_eta_max_scalar = 4000 # Tensor settings should be less than or equal to the above lmax_tensor = 1500 k_eta_max_tensor = 3000 #Main cosmological parameters, neutrino masses are assumed degenerate # If use_phyical set phyiscal densities in baryone, CDM and neutrinos + Omega_k use_physical = T ombh2 = 0.0233 omch2 = 0.0962 omnuh2 = 0 omk = 0 hubble = 78.7 #effective equation of state parameter for dark energy, assumed constant w = −1 #constant comoving sound speed of the dark energy (1=quintessence) cs2_lam = 1 #if use_physical = F set parameters as here #omega_baryon = 0.0376 #omega_cdm = 0.1594 #omega_lambda = 0.803 #omega_neutrino = 0 #massless_neutrinos is the effective number (for QED + non-instantaneous decoupling) temp_cmb = 2.726 helium_fraction = 0.24 massless_neutrinos = 3.04 massive_neutrinos = 0 #Neutrino mass splittings nu_mass_eigenstates = 1 #nu_mass_degeneracies = 0 sets nu_mass_degeneracies = massive_neutrinos #otherwise should be an array #e.g. for 3 neutrinos with 2 non-degenerate eigenstates, nu_mass_degeneracies = 2 1 nu_mass_degeneracies = 0 #Fraction of total omega_nu h2 accounted for by each eigenstate, eg. 0.5 0.5 nu_mass_fractions = 1 #Reionization (assumed sharp), ignored unless reionization = T reionization = T re_use_optical_depth = T re_optical_depth = 0.090 #If re_use_optical_depth = F then use following, otherwise ignored re_redshift = 10.5 re_ionization_frac = 1 #Initial power spectrum, amplitude, spectral index and running initial_power_num = 1 scalar_amp(1) = 21.0e−10 scalar_spectral_index(1) = 0.984 scalar_nrun(1) = 0 tensor_spectral_index(1) = −0.081 #ratio is that of the initial tens/scal power spectrum amplitudes initial_ratio(1) = 0.65 #note vector modes use the scalar settings above #Initial scalar perturbation mode (adiabatic=1, CDM iso=2, Baryon iso=3, # neutrino density iso =4, neutrino velocity iso = 5) initial_condition = 1 #If above is zero, use modes in the following (totally correlated) proportions #Note: we assume all modes have the same initial power spectrum initial_vector = −1 0 0 0 0 #For vector modes: 0 for regular (neutrino vorticity mode), 1 for magnetic vector_mode = 0 #Normalization COBE_normalize = F ##CMB_outputscale scales the output Cls #To get MuK2 set realistic initial amplitude (e.g. scalar_amp(1) = 2.3e−9 above) and #otherwise for dimensionless transfer functions set scalar_amp(1)=1 and use #CMB_outputscale = 1 CMB_outputscale = 7.4311e12 #Transfer function settings, transfer_kmax=0.5 is enough for sigma_8 #transfer_kper_logint=0 sets sensible non-even sampling; #transfer_kper_logint=5 samples fixed spacing in log-k transfer_high_precision = F transfer_kmax = 2 transfer_kper_logint = 0 transfer_num_redshifts = 1 transfer_redshift(1) = 0 transfer_filename(1) = transfer_out.dat #Matter power spectrum output against k/h in units of h&#123;−3} Mpc3 transfer_matterpower(1) = matterpower.dat #Output files not produced if blank. make camb_fits to use use the FITS setting. scalar_output_file = scalCls.dat vector_output_file = vecCls.dat tensor_output_file = tensCls.dat total_output_file = totCls.dat lensed_output_file = lensedCls.dat FITS_filename = scalCls.fits ##Optional parameters to control the computation speed,accuracy and feedback #If feedback_level > 0 print out useful information computed about the model feedback_level = 1 # 1: curved correlation function, 2: flat correlation function, 3: inaccurate harmonic method lensing_method = 1 accurate_BB = F #Recombination calculation: 1: RECFAST, 2: RECFAST+astro-ph/0501672 corrections recombination = 1 #massive_nu_approx: 0 - integrate distribution function # 1 - switch to series in velocity weight once non-relativistic # 2 - use fast approximate scheme (CMB only- accurate for light neutrinos) # 3 - intelligently use the best accurate method massive_nu_approx = 3 #Whether you are bothered about polarization. accurate_polarization = T #Whether you are bothered about percent accuracy on EE from reionization accurate_reionization = F #whether or not to include neutrinos in the tensor evolution equations do_tensor_neutrinos = F #Whether to turn off small-scale late time radiation hierarchies (save time,v. accurate) do_late_rad_truncation = T #Computation parameters #if number_of_threads=0 assigned automatically number_of_threads = 0 #Default scalar accuracy is about 0.3% (except lensed BB). #For 0.1%-level try accuracy_boost=2, l_accuracy_boost=2. #Increase accuracy_boost to decrease time steps, use more k values, etc. #Decrease to speed up at cost of worse accuracy. Suggest 0.8 to 3. accuracy_boost = 2 #Larger to keep more terms in the hierarchy evolution. l_accuracy_boost = 2 #Increase to use more Cl values for interpolation. #Increasing a bit will improve the polarization accuracy at l up to 200 - #interpolation errors may be up to 3% #Decrease to speed up non-flat models a bit l_sample_boost = 1