[Carpet] cctk_{origin, delta}_space not set properly in singlemap mode

[Jonathan Thornburg]

Hi, Erik,

[[recent changes to Carpet]]
> make delta_space undefined in global mode, which proved  
> to be inconvenient for many people.  It is now defined again in  
> global mode as long as only one map is used.  In your case it is  
> still undefined in global mode.  The origin and spacing were always  
> defined in singlemap mode.

Perhaps they were always _supposed_ to be defined, but my test thorn
(based on a fresh darcs checkout of Carpet-devel from 3.Jul.2006) finds
that they're defined in singlemap mode not when multiple maps are present.

That is, I schedule a routine in level mode which then calls
  Carpet::enter_singlemap_mode(GH, map_number)
inside a loop over  map_number  so as to walk through each map in
succession.  The result is that in the singlemap-mode code, origin and
delta are correct for map_number==0, but have incorrect values for all
the other maps.

Moreover, if (in singlemap mode) I do a
  BEGIN_LOCAL_COMPONENT_LOOP(GH, CCTK_GF) ... END_LOCAL_COMPONENT_LOOP
to walk over all grid components of each map, origin and delta are the
same in local mode, i.e. they're correct for map_number==0, and wrong
for all the other maps.

To me this seems like a bug in Carpet.

Do you agree (that it's a bug), or is this a feature (whose "featureness"
I don't yet understand)?

ciao,

-- 
-- Jonathan Thornburg <jthorn at aei.mpg.de>      
   Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut),
   Golm, Germany, "Old Europe"     http://www.aei.mpg.de/~jthorn/home.html      
   "Washing one's hands of the conflict between the powerful and the
    powerless means to side with the powerful, not to be neutral."
                                      -- quote by Freire / poster by Oxfam