[Carpet] Carpet scheduling at evol

[Erik Schnetter]

On Sep 7, 2007, at 13:40:29, Yosef Zlochower wrote:

> Hi,
>
>   I have a question on the scheduling of routines at CCTK_EVOL when
> using carpet.
>
> Suppose I were to setup my thorn such that the three routines
>
> sub_local_1
> sub_level_2
> sub_local_3
>
> were executed in that order with PUGH (This is not necessarily
> accomplished in a straightforward way. The routines may be
> scheduled in different groups). I further specified the
> options: LOCAL for *_local_* routines, and LEVEL for the *_level_*  
> routines.
> Now suppose that I have two levels of refinement (level 0,1) with  
> level
> 1 having
> 2 components. Are the routines called in this order?

The scheduler calls all routines in level mode.  If a routine is  
scheduled in local mode, there will be a loop just around this  
routine, looping over all components.

> cctk_iteration = 1;
>
> sub_local_1 (level=0, component=0)
> sub_level_2 (level=0)
> sub_local_3 (level=0, component=0)
>
> sub_local_1 (level=1, component=0)
> sub_level_2 (level=1)
> sub_local_3 (level=0, component=0)
> sub_local_1 (level=1, component=1)
> sub_local_3 (level=0, component=1)
>
> End of cctk_iteration = 1

No, this order looks incorrect.  It should be instead

cctk_iteration = 1;

sub_local_1 (level=0, component=0)
sub_level_2 (level=0)
sub_local_3 (level=0, component=0)

sub_local_1 (level=1, component=0)
sub_local_1 (level=1, component=1)
sub_level_2 (level=1)
sub_local_3 (level=0, component=0)
sub_local_3 (level=0, component=1)

End of cctk_iteration = 1

Note that this assumes that all 3 routines are either called before  
the fine grid recursion or after.  If not, the order in which the  
levels are called can differ.  The loops over components are not  
affected.

> Does the order depend on which groups the individual routines are
> scheduled in? Does it matter if a schedule group is controlled by
> a "while" expression?

No, the order does not depend on schedule groups.  The schedule is  
decided at startup and then kept fixed; the loops over components are  
added later, at run time, when it is clear how many components there  
are.

While loops are executed by the scheduler in level mode.

-erik

-- 
Erik Schnetter <schnetter at cct.lsu.edu>

My email is as private as my paper mail.  I therefore support encrypting
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