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lesgourg / class_public

Public repository of the Cosmic Linear Anisotropy Solving System (master for the most recent version of the standard code; GW_CLASS to include Cosmic Gravitational Wave Background anisotropies; classnet branch for acceleration with neutral networks; ExoCLASS branch for exotic energy injection; class_matter branch for FFTlog)
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Running CLASS without Ultra-relativistic species? #323

Open avishekdusoye opened 4 years ago

avishekdusoye commented 4 years ago

Hello,

I wanted to run CLASS without Ultra-relativistic species by setting N_ur =0, Is it possible to do that?

Because im having the error

Error in thermodynamics_init =>thermodynamics_init(L:302) :error in thermodynamics_helium_from_bbn(ppr,pba,pth); =>thermodynamics_helium_from_bbn(L:1206) :condition (DeltaNeff < deltaN[0]) is true; You have asked for an unrealistic small value of Delta N_eff = -3.046000e+00. The corresponding value of the primordial helium fraction cannot be found in the interpolation table. If you really want this value, you should fix YHe to a given value rather than to BBN

lesgourg commented 4 years ago

The message you quote gives the explanation of the error, _You have asked for an unrealistic small value of Delta Neff = -3.046000e+00. The corresponding value of the primordial helium fraction cannot be found in the interpolation table. as well as the solution, If you really want this value, you should fix YHe to a given value rather than to BBN. Thus you can add e.g. 'YHe=0.25' to your input parameter list.