taskGNU Astronomy Utilities - Tasks: task #14689, faster ageofuniverse in cosmology...


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task #14689: faster ageofuniverse in cosmology library + other cosmo extensions

Submitted by:  Boud Roukema <boud>
Submitted on:  Tue 03 Oct 2017 02:53:24 PM UTC  
Should Start On:  Tue 03 Oct 2017 12:00:00 AM UTC Should be Finished on:  Wed 03 Oct 2018 12:00:00 AM UTC
Category:  Libraries Priority:  5 - Normal
Item Group:  Enhancement Status:  In Progress
Privacy:  Public Percent Complete:  20%
Assigned to:  Boud Roukema <boud> Open/Closed:  Open
Effort:  0.00

Tue 03 Oct 2017 02:53:24 PM UTC, original submission:

See https://bitbucket.org/broukema/gnuastro/branch/cosmo-dev
for a proof-of-concept of a 100x speed up for Universe ages.
It's a bit hacked but enough to get started on
improving the cosmo functions, I think.

I get the output from commit dd4443a :

ageofuniverse benchmark: old 1.81705  new 0.013959, old/new 130.17

I don't think we'll get much of a speed-up in proper distances
compared to https://arxiv.org/abs/1702.0886 (ignore the comments
there about luminosity distance being the main distance; it's
main in terms of observational analysis, but proper distance
is simpler in terms of the FLRW models.)

We would need an analytical integral of (sinh x)^(-2/3), because
d_{radial_comoving} = \int c dt/a(t) - see

The best that https://en.wikipedia.org/wiki/List_of_integrals_of_hyperbolic_functions suggests
would be to rewrite it in terms of \int (sinh x)^(4/3) , which
wouldn't help much. :P

We can implement what looks best for proper distances after re-reading 1702.0886.

The non-flat cases should be added too.

Boud Roukema <boud>
Project MemberIn charge of this item.


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