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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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a very small quantity of Dark Matter ( given by omega_cdm into CLASS and Hi-CLASS). #576

Open AndreV84 opened 3 months ago

AndreV84 commented 3 months ago

Could you suggest how to resolve the error, please? from devs:

Error in Class: background_init(L:746) :error in background_solve(ppr,pba);
=>background_solve(L:2282) :condition (pba->min_cs2_smg < -fabs(pba->cs2_safe_smg)) is true; Gradient instability for scalar field perturbations with minimum c_s^2=-1092.93

input:

params = {
'Omega_Lambda' : '0.0',
'Omega_fld' : '0.0',
A_planck = 1.0

params = {
'Omega_Lambda' : '0.0',
'Omega_fld' : '0.0',
'Omega_smg' : '-1.0',
'gravity_model' : 'brans dicke',
'lensing': 'yes',
'l_max_scalars': str(lmax),
'a_min_stability_test_smg' : '3e-13',
'output_background_smg': '10',
'write parameters': 'no',
'write background': 'no',
'write thermodynamics': 'no',
'input_verbose' : '0',
'background_verbose' : '0',
'output_verbose' : '0',
'thermodynamics_verbose' : '0',
'perturbations_verbose' : '0',
'spectra_verbose' : '0',
'omega_b' : '0.022032',
#'omega_cdm' : '1e-3',
'omega_cdm' : '1e-6',
'gauge' : 'Synchronous',
'YHe': '0.245',
'H0' : '67.4',
#'pert_ic_tolerance_smg': '1e-6', # Exemple d'ajustement
}

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