reionization model in the .param file

[ming-jian]

Dear all,
I am currently working on a reionization study using Montepython 3.6 + CLASS 3.1.0. I have chosen the reio_many_tanh model to describe the reionization history and intend to split the process into 2 step. Specifically, I wish to treat the following parameters as free parameters to be constrained by data fitting:

many_tanh_z (redshift of reionization transition)

many_tanh_xe (corresponding ionization fraction)

many_tanh_width (width of the reionization transition)

However, I have encountered some difficulties in setting up the .param file. I am unsure how to properly define these parameters as free parameters and interface them with Montepython. I tried setting parameters using forms like many_tanh_z[0], many_tanh_z[1], but the run keeps failing with the error: Entry 'many_tanh_z' is required but not found!"

[brinckmann]

Hi Ming-Jian,

I'm not familiar with the parameters, but the notation in MontePython would be e.g.
many_tanh_z__1
many_tanh_z__2
many_tanh_z__3
Which would then be collected into a list (a string) with each entry in the variable many_tanh_z , which gets passed to CLASS.
You can see the behavior on line 1246-1261 of montepython/data.py in the default MontePython

I hope this helps!

Best,
Thejs

[ming-jian]

Dear Thejs,
Thanks very much for your kind help ! Your guidance has been very effective. After multiple attempts and debugging, the program can finally run. I have written down the relevant settings below, which may be helpful for others

data.experiments=['Planck20_Hillipop_TTTEEE','Planck_lowl_TT','Planck20_Lollipop_EE','desi_2025_gaussian_bao_all', 'sn_union3']
data.over_sampling=[1, 4]

data.parameters['omega_b'] = [0.0223, 0.017, 0.027, 0.0002, 1, 'cosmo']
data.parameters['omega_cdm'] = [0.1188, 0.09, 0.15, 0.002, 1, 'cosmo']
data.parameters['n_s'] = [ 0.968, 0.9, 1.1, 0.005, 1, 'cosmo']
data.parameters['ln10^{10}A_s'] = [ 3.040, 2.7, 3.4, 0.02, 1, 'cosmo']

data.parameters['100*theta_s'] = [1.0410, 1.03, 1.05, 0.0003, 1, 'cosmo']

data.parameters['many_tanh_z__1'] = [6.5, 4.5, 8.0, 0.01, 1, 'cosmo'] #Note：The last subscript is double underlined _ _1
data.parameters['many_tanh_z__2'] = [15.0, 10.0, 25.0, 0.01, 1, 'cosmo'] #Note：The last subscript is double underlined _ _2
data.parameters['many_tanh_xe__1'] = [0.99, 0.95, 1.02, 0.01, 1, 'cosmo']
data.parameters['many_tanh_xe__2'] = [0.08, 0.02, 0.25, 0.01, 1, 'cosmo']
data.parameters['many_tanh_width__1'] = [0.3, 0.1, 0.6, 0.01, 1, 'cosmo']
data.parameters['many_tanh_width__2'] = [4.0, 1.0, 6.0, 0.01, 1, 'cosmo']

data.parameters['tau_reio'] = [0, None, None, 0, 1, 'derived']
data.parameters['z_reio'] = [0, None, None, 0, 1, 'derived']

data.cosmo_arguments['reio_parametrization'] = 'reio_many_tanh'
data.cosmo_arguments['many_tanh_num'] = 2

[brinckmann]

Hi Ming-Jian,

Thank you for reporting back! A heads up that you can't have commented lines after parameters in your MontePython param file, or it will cause problems.

I.e. please use

#Note：The last subscript is double underlined _ _1
data.parameters['many_tanh_z__1'] = [6.5, 4.5, 8.0, 0.01, 1, 'cosmo']
#Note：The last subscript is double underlined _ _2
data.parameters['many_tanh_z__2'] = [15.0, 10.0, 25.0, 0.01, 1, 'cosmo'] 

instead of

data.parameters['many_tanh_z__1'] = [6.5, 4.5, 8.0, 0.01, 1, 'cosmo'] #Note：The last subscript is double underlined _ _1
data.parameters['many_tanh_z__2'] = [15.0, 10.0, 25.0, 0.01, 1, 'cosmo'] #Note：The last subscript is double underlined _ _2

Best,
Thejs