[mpich-discuss] 32bit and 64bit system issues

[Samir Khanal]

Hi all

I have a code that has some problems while used in the 64bit system

it runs very well on 32bit system (single core) with mpich-1.2.7 / PBS

but the same thing when compiled for and ran for mpich-1.2.7 / PBS on a 64 bit system just hangs up. (Goes on for a while, This one is a quad core system)

#PBS -n nodes=4:ppn=4
I did 
mpiexec -n 4 -pernode ./a.out
to make it look like a single core system. (correct me if i am wrong...)

Both of the 32 and 64 bits systems are rocks clusters 5.1

Is there any drastic change moving from 32 to 64 bit system and from single core to quad core system?
Anything to be careful about?

Thanks
Samir