lesgourg/class_public

Problems with Three parameter Dark energy models

Physics-16 opened this issue · 2 comments

Physics-16 commented

I am facing a problem while running MontePython with CLASS for a Three parameter model of Dark Energy. I have modified the files like- background.c, background.h and input.c in order to implement a new Three parameter model of Dark Energy (w1,w2,w3). The error I am facing, is the following:-

Error in Class: perturbations_init(L:1007) :error in perturbations_solve(ppr, pba, pth, ppt, index_md, index_ic, index_k, pppw[thread]);
=>perturbations_solve(L:3318) :error in generic_evolver(perturbations_derivs, interval_limit[index_interval], interval_limit[index_interval+1], ppw->pv->y, ppw->pv->used_in_sources, ppw->pv->pt_size, &ppaw, ppr->tol_perturbations_integration, ppr->smallest_allowed_variation, perturbations_timescale, ppr->perturbations_integration_stepsize, ppt->tau_sampling, tau_actual_size, perturbations_sources, perhaps_print_variables, ppt->error_message);
=>evolver_ndf15(L:466) :condition (absh <= hmin) is true; Step size too small: step:2.27188e-11, minimum:2.27188e-11, in interval: [2.48908:350.106]

In the .param file of the MontePython folder, I have used the following initial values for the Equation of State parameters of Dark Energy:-

data.parameters['w1_fld'] = [ -0.98, -3, -0.3, 0.15, 1, 'cosmo']
data.parameters['w2_fld'] = [ 0.0, -2.0, 0.6, 0.15, 1, 'cosmo']
data.parameters['w3_fld'] = [ 0.01, None, None, 0.15, 1, 'cosmo']

I don't know why am I facing this problem for a Three parameter model of DE. Since I have successfully ran all Two parameter models of DE (like- CLP) without any problem.
So it will be really helpful if anybody will suggest something for the resolution of this issue?

schoeneberg commented

Dear @Physics-16 , it looks to me like there is something broken with your implementation of the Three parameter model. Since that is related to how you changed the code, I am afraid we cannot help you without a look at your complete code base

Kshitizpandey123 commented

Hi, can you help me with a parametrized model?
I this model I am trying, I have one parameter, say "alpha". I don't have w0_fld or wa_fld in the equation of state expression. I have modified the background.c , included the "alpha" in the header file and also modified input.c.
(Though I am not sure I have done all the changes required in input.c)

I also included this parameter in the param file and ran it, but it says:
Cosmological Module Error:
/|\ Something went wrong when calling CLASS
/o\ Error in Class: Class did not read input parameter(s): alpha