[Users] #1070: EOS_Omni::poly_gamma_ini should default to poly_gamma

[Frank Loeffler]

Hi

I forward this ticket to the users mailing list such that there can be
a wider circle of people coming to an agreement.

Frank


#1070: EOS_Omni::poly_gamma_ini  should default to poly_gamma
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 Reporter:  knarf                  |       Owner:                     
     Type:  enhancement            |      Status:  new                
 Priority:  minor                  |   Milestone:                     
Component:  EinsteinToolkit thorn  |     Version:  development version
 Keywords:                         |  
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 At the moment, EOS_Omni::poly_gamma and EOS_Omni::poly_gamma_ini are two
 parameters for the adiabatic exponent, one used only for initial data, the
 other for evolutions. Both default to 2.0. This means that if someone,
 unaware of poly_gamma_ini, changes only poly_gamma the result is usually
 catastrophic (wrong results or c2p failures). I myself didn't notice today
 and had to debug my way down to find my mistake.

 I propose to make the default of EOS_Omni::poly_gamma_ini to be whatever
 EOS_Omni::poly_gamma is. One way to achieve that would be to use some
 special value for EOS_Omni::poly_gamma_ini which would usually not being
 used to indicate that behavior and to make that default. However, this
 being an exponent, at least in theory, all real values are allowed.
 Another approach would be to introduce a new boolean parameter which would
 allow users to use an initial value for gamma which is different from the
 one of the initial data. This would be 'saver', but has the drawback of a
 new parameter. Nevertheless, I favor the second approach.

-- 
Ticket URL: <https://trac.einsteintoolkit.org/ticket/1070>
Einstein Toolkit <http://einsteintoolkit.org>
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