[Carpet] potential integer overflow in Grid setup

[Thomas Radke]

Hi Erik,

yesterday I fixed the CarpetIOHDF5 testsuites, and during the last 
night's integration tests they passed on all machines - except on 
Pelican.lsu.edu (an IBM SP5). Running the testsuite 
CarpetWaveToyNewRecover_test_1proc.par I get the following error:

> INFO (Carpet): Base grid specification for map 0:
>    number of grid points : [20,20,20]
>    number of ghost points: [[2,2,2],[2,2,2]]
> WARNING level 0 in thorn CarpetLib processor 0 host peg304.hpc.lsu.edu
>   (line 31 of /scratch/tradke/Cactus/configs/PublicThorns/build/CarpetLib/bbox.cc): 
>   -> Tried to create a very large bbox -- it is likely that this would lead to an integer overflow
> WARNING level 0 in thorn CarpetLib processor 0 host peg304.hpc.lsu.edu
>   (line 31 of /scratch/tradke/Cactus/configs/PublicThorns/build/CarpetLib/bbox.cc): 
>   -> Tried to create a very large bbox -- it is likely that this would lead to an integer overflow
> The assert subroutine failed: 0, file /scratch/tradke/Cactus/configs/PublicThorns/build/Carpet/helpers.cc, line 150

-- 
Cheers, Thomas.