### Cobaya and CLASS: comparing to Planck 2018 tables

Posted:

**April 10 2020**I am running cobaya with CLASS, trying to match parameters and output of 2.20 on pg 29 of the Planck 2018 baseline parameters tables here.

I used the cobaya-cosmo-generator to build a basic input .yaml file which I modified to run on H0, point to installations, use the evaluate sampler and pass nuisance parameter values for Planck.

Here are the input parameters I am passing through cobaya under the evaluate sampler using the override option:

logA = 3.0476

n_s = 0.96822

H0 = 67.742

omega_b = 0.022436

omega_cdm = 0.11914

tau_reio = 0.0566

A_planck = 1.00068

calib_100T = 0.99973

calib_217T = 0.99817

A_cib_217 = 46.3

xi_sz_cib = 0.595

A_sz = 7.15

ksz_norm = 0.01

gal545_A_100 = 8.83

gal545_A_143 = 11.02

gal545_A_143_217 = 20.07

gal545_A_217 = 95.3

ps_A_100_100 = 248.3

ps_A_143_143 = 49.4

ps_A_143_217 = 51.4

ps_A_217_217 = 121.1

galf_TE_A_100 = 0.1139

galf_TE_A_100_143 = 0.1339

galf_TE_A_100_217 = 0.479

galf_TE_A_143 = 0.224

galf_TE_A_143_217 = 0.666

galf_TE_A_217 = 2.08

Here’s the output I get:

2020-04-10 10:44:34,176 [evaluate] log-posterior = -1939.61

2020-04-10 10:44:34,177 [evaluate] log-prior = -21.7161

2020-04-10 10:44:34,177 [evaluate] logprior_0 = -19.4873

2020-04-10 10:44:34,177 [evaluate] logprior_SZ = -2.2288

2020-04-10 10:44:34,177 [evaluate] log-likelihood = -1917.89

2020-04-10 10:44:34,177 [evaluate] chi2_planck_2018_lowl.TT = 22.835

2020-04-10 10:44:34,177 [evaluate] chi2_planck_2018_lowl.EE = 396.477

2020-04-10 10:44:34,177 [evaluate] chi2_planck_2018_highl_plik.TTTEEE = 2344.93

2020-04-10 10:44:34,177 [evaluate] chi2_planck_2018_lensing.clik = 8.81844

2020-04-10 10:44:34,177 [evaluate] chi2_bao.sixdf_2011_bao = 0.0229754

2020-04-10 10:44:34,177 [evaluate] chi2_bao.sdss_dr7_mgs = 1.29716

2020-04-10 10:44:34,177 [evaluate] chi2_bao.sdss_dr12_consensus_bao = 4.26967

2020-04-10 10:44:34,177 [evaluate] chi2_sn.pantheon = 1034.98

2020-04-10 10:44:34,177 [evaluate] chi2_my_H0 = 22.1479

2020-04-10 10:44:34,177 [evaluate] Derived params:

2020-04-10 10:44:34,177 [evaluate] A_s = 2.10647e-09

2020-04-10 10:44:34,177 [evaluate] Omega_m = 0.309917

2020-04-10 10:44:34,177 [evaluate] omegamh2 = 0.14222

2020-04-10 10:44:34,177 [evaluate] Omega_Lambda = 0.690004

2020-04-10 10:44:34,177 [evaluate] YHe = 0.245421

2020-04-10 10:44:34,177 [evaluate] z_reio = 7.88554

2020-04-10 10:44:34,177 [evaluate] sigma8 = 0.809922

2020-04-10 10:44:34,177 [evaluate] s8h5 = 0.984043

2020-04-10 10:44:34,177 [evaluate] s8omegamp5 = 0.450885

2020-04-10 10:44:34,177 [evaluate] s8omegamp25 = 0.604302

2020-04-10 10:44:34,177 [evaluate] A = 2.10647

2020-04-10 10:44:34,177 [evaluate] clamp = 1.88102

2020-04-10 10:44:34,177 [evaluate] age = 13.7846

2020-04-10 10:44:34,177 [evaluate] rs_drag = 147.25

2020-04-10 10:44:34,177 [evaluate] chi2__CMB = 2773.07

2020-04-10 10:44:34,178 [evaluate] chi2__BAO = 5.58981

I have a few questions about this and would appreciate any help:

I used the cobaya-cosmo-generator to build a basic input .yaml file which I modified to run on H0, point to installations, use the evaluate sampler and pass nuisance parameter values for Planck.

Here are the input parameters I am passing through cobaya under the evaluate sampler using the override option:

logA = 3.0476

n_s = 0.96822

H0 = 67.742

omega_b = 0.022436

omega_cdm = 0.11914

tau_reio = 0.0566

A_planck = 1.00068

calib_100T = 0.99973

calib_217T = 0.99817

A_cib_217 = 46.3

xi_sz_cib = 0.595

A_sz = 7.15

ksz_norm = 0.01

gal545_A_100 = 8.83

gal545_A_143 = 11.02

gal545_A_143_217 = 20.07

gal545_A_217 = 95.3

ps_A_100_100 = 248.3

ps_A_143_143 = 49.4

ps_A_143_217 = 51.4

ps_A_217_217 = 121.1

galf_TE_A_100 = 0.1139

galf_TE_A_100_143 = 0.1339

galf_TE_A_100_217 = 0.479

galf_TE_A_143 = 0.224

galf_TE_A_143_217 = 0.666

galf_TE_A_217 = 2.08

Here’s the output I get:

2020-04-10 10:44:34,176 [evaluate] log-posterior = -1939.61

2020-04-10 10:44:34,177 [evaluate] log-prior = -21.7161

2020-04-10 10:44:34,177 [evaluate] logprior_0 = -19.4873

2020-04-10 10:44:34,177 [evaluate] logprior_SZ = -2.2288

2020-04-10 10:44:34,177 [evaluate] log-likelihood = -1917.89

2020-04-10 10:44:34,177 [evaluate] chi2_planck_2018_lowl.TT = 22.835

2020-04-10 10:44:34,177 [evaluate] chi2_planck_2018_lowl.EE = 396.477

2020-04-10 10:44:34,177 [evaluate] chi2_planck_2018_highl_plik.TTTEEE = 2344.93

2020-04-10 10:44:34,177 [evaluate] chi2_planck_2018_lensing.clik = 8.81844

2020-04-10 10:44:34,177 [evaluate] chi2_bao.sixdf_2011_bao = 0.0229754

2020-04-10 10:44:34,177 [evaluate] chi2_bao.sdss_dr7_mgs = 1.29716

2020-04-10 10:44:34,177 [evaluate] chi2_bao.sdss_dr12_consensus_bao = 4.26967

2020-04-10 10:44:34,177 [evaluate] chi2_sn.pantheon = 1034.98

2020-04-10 10:44:34,177 [evaluate] chi2_my_H0 = 22.1479

2020-04-10 10:44:34,177 [evaluate] Derived params:

2020-04-10 10:44:34,177 [evaluate] A_s = 2.10647e-09

2020-04-10 10:44:34,177 [evaluate] Omega_m = 0.309917

2020-04-10 10:44:34,177 [evaluate] omegamh2 = 0.14222

2020-04-10 10:44:34,177 [evaluate] Omega_Lambda = 0.690004

2020-04-10 10:44:34,177 [evaluate] YHe = 0.245421

2020-04-10 10:44:34,177 [evaluate] z_reio = 7.88554

2020-04-10 10:44:34,177 [evaluate] sigma8 = 0.809922

2020-04-10 10:44:34,177 [evaluate] s8h5 = 0.984043

2020-04-10 10:44:34,177 [evaluate] s8omegamp5 = 0.450885

2020-04-10 10:44:34,177 [evaluate] s8omegamp25 = 0.604302

2020-04-10 10:44:34,177 [evaluate] A = 2.10647

2020-04-10 10:44:34,177 [evaluate] clamp = 1.88102

2020-04-10 10:44:34,177 [evaluate] age = 13.7846

2020-04-10 10:44:34,177 [evaluate] rs_drag = 147.25

2020-04-10 10:44:34,177 [evaluate] chi2__CMB = 2773.07

2020-04-10 10:44:34,178 [evaluate] chi2__BAO = 5.58981

I have a few questions about this and would appreciate any help:

- the outputs for \sigma_8 and S8 don’t match the Planck tables, but everything else does. The Planck tables use CAMB, are CLASS and CAMB is disagreement about S8 values? I am using an older version of CLASS, and that might be it. I'll run tests myself to eliminate that possibility, but asking incase someone already had the answer!
- I am not getting the same value for the Pantheon likelihood as in the Planck tables (10362.26). Moreover, I don’t see in cobaya output any nuisance parameter for Pantheon - is cobaya varying Pantheon nuisance params?
- Lastly, the BAO likelihood code under _bao_prototype.py mentions that BAO likelihoods are not yet compatible with CLASS? Has this issue been resolved? As I’m seeing nearly identical BAO chi^2’s between the Planck tables and my cobaya output.