CosmoCoffee Forum Index CosmoCoffee

 
 FAQFAQ   SearchSearch  MemberlistSmartFeed   MemberlistMemberlist    RegisterRegister 
   ProfileProfile   Log inLog in 
Arxiv New Filter | Bookmarks & clubs | Arxiv ref/author:

CAMB: calculating derivatives of Cl's wrt parameters
 
Post new topic   Reply to topic    CosmoCoffee Forum Index -> Computers and software
View previous topic :: View next topic  
Author Message
Graeme Addison



Joined: 17 Jul 2014
Posts: 16
Affiliation: Johns Hopkins University

PostPosted: August 08 2017  Reply with quote

Is there any way to have CAMB calculate derivatives of CMB power spectra with respect to cosmological parameters? I.e. quantities like \frac{\partial C_{\ell}}{\partial(\Omega_ch^2)}

I can numerically estimate derivatives by perturbing parameters and re-running but wanted to check if there's some better / more efficient way.

Thanks
Back to top
View user's profile  
Antony Lewis



Joined: 23 Sep 2004
Posts: 1300
Affiliation: University of Sussex

PostPosted: August 09 2017  Reply with quote

That's usually the best way. (unless you really want parameter errors/forecasts - in which case run CosmoMC).
Back to top
View user's profile [ Hidden ] Visit poster's website
Graeme Addison



Joined: 17 Jul 2014
Posts: 16
Affiliation: Johns Hopkins University

PostPosted: August 10 2017  Reply with quote

OK. How about if I want to evaluate these derivatives at each step of a CosmoMC chain? Can I have CAMB called multiple times at each step with slightly different parameters?
Back to top
View user's profile  
Antony Lewis



Joined: 23 Sep 2004
Posts: 1300
Affiliation: University of Sussex

PostPosted: August 10 2017  Reply with quote

You probably could, but it might take some thought on how to code it.
Back to top
View user's profile [ Hidden ] Visit poster's website
Graeme Addison



Joined: 17 Jul 2014
Posts: 16
Affiliation: Johns Hopkins University

PostPosted: August 10 2017  Reply with quote

Hmm OK. I think I'll start with figuring out how much the derivatives are really varying in case I don't need to do the recalculation each step. Thanks.
Back to top
View user's profile  
Display posts from previous:   
Post new topic   Reply to topic    CosmoCoffee Forum Index -> Computers and software All times are GMT + 5 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group. Sponsored by WordWeb online dictionary and dictionary software.