[ET Trac] [Einstein Toolkit] #620: Simplify timelevel handling for Cactus thorn writers

[Einstein Toolkit]

#620: Simplify timelevel handling for Cactus thorn writers
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  Reporter:  hinder       |       Owner:     
      Type:  enhancement  |      Status:  new
  Priority:  major        |   Milestone:     
 Component:  Cactus       |     Version:     
Resolution:               |    Keywords:     
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Comment (by eschnett):

 Each timelevel is stored in its own variable, e.g. gxx, gxx_p, gxx_p_p,
 etc. The number of timelevels declared in interface.ccl defines how many
 of these variables will be passed into each subroutine, and thus needs to
 be known at build time.

 The number of timelevels that is allocated is much more flexible; this is
 the number specified in the schedule.ccl file.

 There is, in principle, nothing wrong with allocating more timelevels than
 there are variables. The additional timelevels could not be accessed in
 "straightforward" code, but are still visible e.g. via CCTK_VarDataPtr.

 That is, it should be fairly easy to do away with the maximum number of
 timelevels. The number of timelevels declared in the interface.ccl becomes
 the number of timelevels directly accessible in the code -- typically only
 1 is necessary, except if past timelvels are initialised explicitly, which
 is rarely a convenient way to do so.

-- 
Ticket URL: <https://trac.einsteintoolkit.org/ticket/620#comment:1>
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