CAMB, unable to perform complicated calculations

 Posts: 7
 Joined: August 19 2018
 Affiliation: IAUCTB
CAMB, unable to perform complicated calculations
I have written equations of a holographic dark energy model with interaction in CAMB. (w_de rho_de which are ODE and must be solved numerically).
I have tested the CAMB with simple code and it printed list of numbers so fast and plotted it using Gnuplot.
But, as I replace the equations with my model, CAMB takes more than 10 hours to print just half of that list while saying rombint failed to converge...
I do not know how should I do, the equation I wrote for my model is ODE which works properly. I use RungeKutta 45 for solving that (w_de)
this is my w_de
w_de =1(1/(3 * rkomgd(a))) * (3 * wa_ppf * (rkomgd(a) + rkomgd(a)**2/((3 * rkomgd(a)/w_lam**2)  2)) + 3 + rkomgd(a) * (2  3/(w_lam**2))) * (3 * (2 + rkomgd(a) * ((3/w_lam**2)  1)) + 3 * wa_ppf * (rkomgd(a) + rkomgd(a)**2/((3 * rkomgd(a)/w_lam**2)  2)))/(rkomgd(a) * ((3/w_lam**2)  1)  w_lam**2  1)
in which rkomgd(a) is solving another fuction using runge kutta
also my qrho_de is rkomgd(a)
I have tested the CAMB with simple code and it printed list of numbers so fast and plotted it using Gnuplot.
But, as I replace the equations with my model, CAMB takes more than 10 hours to print just half of that list while saying rombint failed to converge...
I do not know how should I do, the equation I wrote for my model is ODE which works properly. I use RungeKutta 45 for solving that (w_de)
this is my w_de
w_de =1(1/(3 * rkomgd(a))) * (3 * wa_ppf * (rkomgd(a) + rkomgd(a)**2/((3 * rkomgd(a)/w_lam**2)  2)) + 3 + rkomgd(a) * (2  3/(w_lam**2))) * (3 * (2 + rkomgd(a) * ((3/w_lam**2)  1)) + 3 * wa_ppf * (rkomgd(a) + rkomgd(a)**2/((3 * rkomgd(a)/w_lam**2)  2)))/(rkomgd(a) * ((3/w_lam**2)  1)  w_lam**2  1)
in which rkomgd(a) is solving another fuction using runge kutta
also my qrho_de is rkomgd(a)

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 Joined: September 23 2004
 Affiliation: University of Sussex
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Re: CAMB, unable to perform complicated calculations
For the background evolution you should precompute and interpolate the functions, like what use_tabulated_w option does for equations_ppf or the improved devel branch.

 Posts: 7
 Joined: August 19 2018
 Affiliation: IAUCTB
Re: CAMB, unable to perform complicated calculations
Thank you. my rho_de is ODE. If I use w_de from table, solving rho_de gets error again?Antony Lewis wrote: ↑August 24 2018For the background evolution you should precompute and interpolate the functions, like what use_tabulated_w option does for equations_ppf or the improved devel branch.

 Posts: 7
 Joined: August 19 2018
 Affiliation: IAUCTB
Re: CAMB, unable to perform complicated calculations
Nope, it works properly using table and rungekutta simultaneously.ehsan sadri wrote: ↑August 24 2018Thank you. my rho_de is ODE. If I use w_de from table, solving rho_de gets error again?Antony Lewis wrote: ↑August 24 2018For the background evolution you should precompute and interpolate the functions, like what use_tabulated_w option does for equations_ppf or the improved devel branch.