Shooting Stops before reaching Target for Omega_scf

[HengamehB]

Hello,

I modified class at the background level to add a coupling between DM and DE ( of the form m(DM) = exp(-scf_beta*phi)). In doing so, I

• introduce a new parameter (i.e. scf_beta)
• modified the definition of rho_scf in background_functions()
• modified EOM for scf in backgorounds_derivs()
• modified the scalar field potential to be of the form scf_A exp(-lambda * phi)
• modified dxdy in input_get_guess() to exp(-lambda * phi)

The code almost works, except that the shooting never really kicks in. It seems to stop before reaching the target value. Here is what I get (any help is much appreciated):

Reading input parameters
Computing unknown input parameter 'scf_shooting_parameter' using input parameter 'Omega_scf'
-> matched budget equations by adjusting Omega_scf = 0.688047
scf_beta = 0.05
-> matched budget equations by adjusting Omega_scf = 0.688047
scf_beta = 0.05
Stage 1: background
Not using attractor initial conditions
-> found 'scf_shooting_parameter = 1.50000000000000000000e+00'
Shooting completed using 1 function evaluations
-> matched budget equations by adjusting Omega_scf = 0.688047
scf_beta = 0.05
Running CLASS version v3.3.3
Computing background
Not using attractor initial conditions
Chose ndf15 as generic_evolver
-> age = 13.781126 Gyr
-> conformal age = 14177.166842 Mpc
-> N_eff = 3.044 (summed over all species that are non-relativistic at early times)
Scalar field details:
-> Omega_scf = 0.672963, wished 0.688047
-> parameters: [lambda, alpha, A, B] =
[1.000, 0.000, 1.500, 0.000, 0.000, 0.000]
-> radiation/matter equality at z = 3374.624883
corresponding to conformal time = 113.756826 Mpc
---------------------------- Budget equation -----------------------
---> Nonrelativistic Species
-> Bayrons Omega = 0.04959 , omega = 0.0224607
-> Cold Dark Matter Omega = 0.262271 , omega = 0.11879
---> Relativistic Species
-> Photons Omega = 5.45997e-05 , omega = 2.47298e-05
-> Ultra-relativistic relics Omega = 3.77456e-05 , omega = 1.70961e-05
---> Other Content
-> Scalar Field Omega = 0.688047 , omega = 0.311636
---> Total budgets
Radiation Omega = 9.23453e-05 , omega = 4.18259e-05
Non-relativistic Omega = 0.311861 , omega = 0.141251
Other Content Omega = 0.688047 , omega = 0.311636
TOTAL Omega = 1 , omega = 0.452929

Computing thermodynamics using HyRec 2020
-> with primordial helium mass fraction Y_He = 0.2453
-> recombination (maximum of visibility function) at z = 1088.588446
corresponding to conformal time = 281.325686 Mpc
with comoving sound horizon = 144.797936 Mpc
angular diameter distance = 12.753293 Mpc
sound horizon angle 100theta_s = 1.042024
Thomson optical depth crosses one at z_ = 1084.874033
giving an angle 100theta_ = 1.044418
-> baryon drag stops at z = 1059.991051
corresponding to conformal time = 286.961486 Mpc
with comoving sound horizon rs = 147.343741 Mpc
-> reionization with optical depth = 0.054639
corresponding to conformal time = 5152.133183 Mpc
No sources requested. Perturbation module skipped.
No perturbations requested. Primordial module skipped.
No harmonic space transfer functions to compute. Transfer module skipped.
No lensing requested. Lensing module skipped.

[adriantee625]

I believe this behaviour may share the same root cause as reported in my new issue: #646. I traced it to an early-exit condition in input.c, which can be temporarily bypassed by commenting out the relevant lines.

Cheers,
Adrian