[Carpet] potential integer overflow in Grid setup

[Erik Schnetter]

On Mar 18, 2008, at 08:59:42, Thomas Radke wrote:

> 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


Interesting.  This test checks whether one edge of the box is longer  
than INTMAX/2.  Either this machine uses 4 bit integers, or the  
corresponding STL entries to determine the limits of data types are  
broken.

There is a bit of a complication since the minimum of an integer  
quantity is a large negative number (the smallest integer), whereas  
the minimum of a real quantity is a very small positive number (the  
smallest POSITIVE real).  It could thus be that the distinction  
between integers and reals doesn't work.  I don't assume there is a  
core file...?

-erik

-- 
Erik Schnetter <schnetter at cct.lsu.edu>   http://www.cct.lsu.edu/~eschnett/

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