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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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Problem in perturbation evolution #446

Open SafaeCosmology opened 3 years ago

SafaeCosmology commented 3 years ago

Hi everyone, please, I have a problem in CLASS, If anyone can help me. in fact I work on the interaction between dark matter and dark energy (phantom dark energy model) model, I made modifications only in input.c, background.h /.c, and perturbations.c, but when I use use_ppf = no in my input file (.ini) I get the following error :

_Computing sources Error in perturbations_init =>perturbations_init(L:583) :condition ((w_fld_0 == -1.) && (dw_over_da_fld == 0.)) is true; Your choice of a fluid with (w0,wa)=(-1,0) is not valid due to instabilities in the unphysical perturbations of such a fluid. Try instead with a plain cosmological constant or with PPF scheme: useppf = yes

but when I use use_ppf = yes I get the following error :

Computing sources Segmentation fault (core dumped).

thanks in advance

msabogal commented 2 years ago

Hi SafaeCosmology,

I don't know if you still need the answer, if you do:

It seems that in your model w takes values under -1 (phantom zone), that provoke instabilities in the perturbations equations. You should change the implemation of your model (on perturbations.c) for ppf, or only consider w values over -1.

Good luck.