[Feature Req] Direct calculation of growth factor for alternative dark energy models

[steven-murray]

Is your feature request related to a problem? Please describe.
It would be good to not have to have CAMB available to compute growth factors for dark energy models (plus it's slower for this since the calculation is to compute the transfer functions).

Describe the solution you'd like
Implement DE.

[camarman]

Dear Steven Murray,

I am a M.Sc. Physics student in Istanbul Technical University. For my masters studies, I have tried to implement different DE parametrizations via astropy modules. In some cases I am getting errors that claims I cannot implement any other DE model then LCDM and wCDM (depending on the growth_model and transfer_model). Is it really the case ?

Sincerely,
Arman

[steven-murray]

Yeah, this is the case. I'd be willing to accept PRs that expand the capabilities though!

[camarman]

Yeah, this is the case. I'd be willing to accept PRs that expand the capabilities though!

I would like to help but I am not sure where to start...But I'll try to look in my free tlmes.

I also wonder, is it possible to obtain the DE information from CAMB and later on add it to hmf so that I can produce plots?

PS: In the transfer_models there are FromArray and FromFile options. Is it possible to use them for different type of DE parametrizations ? Or I should use CAMB or maybe some other program to produce HMF/Stellar Mass Density plots ?

Thanks

[steven-murray]

I think the main thing you need to do is make sure your transfer function and the growth factor calculation are correct. You can do that however you like, either using in-built classes in hmf or adding your own. The FromArray and FromFile options might be an easy patch for now, if you can get the info from camb.

[camarman]

I see your point. Thanks for the help. I will try to perform both approaches, but first, I am going to try to add the equations in the hmf.