[ET Trac] [Einstein Toolkit] #1070: EOS_Omni::poly_gamma_ini should default to poly_gamma
Einstein Toolkit
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Tue Sep 4 09:47:09 CDT 2012
#1070: EOS_Omni::poly_gamma_ini should default to poly_gamma
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Reporter: knarf | Owner:
Type: enhancement | Status: review
Priority: minor | Milestone:
Component: EinsteinToolkit thorn | Version: development version
Resolution: | Keywords:
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Comment (by knarf):
Right. I also find it a bit confusing to have cgs units used for constants
in the code but then transforming back and forth all the time to cancel
them out again. At the moment, a polytrope is calculated as p = K *
rho^poly_gamma * magic_number^(poly_gamma_ini - poly_gamma) where
magic_number is defined in EOS_Omni_Module.F90 with the comment:
> Magic numbers in convenient units, calculated by someone whom we trust
to have worked very carefully
I think there are two separate issues here. The first is the question why
these units are used in the first place - why converting poly_k to
poly_k_cgs if inside the EOS we use p_gf and rho_gf to reverse it again.
The second issue is that at the moment poly_gamma_ini isn't really doing
what it is supposed to be doing. It would be correct if poly_k_cgs would
be reset to poly_k * rho_gf^poly_gamma / p_gf after it has been used for
initial data.
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Ticket URL: <https://trac.einsteintoolkit.org/ticket/1070#comment:6>
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