[lammps-users] Got error: Failed to reallocate 1265040 bytes for array atom:x

Dear Friends,

I’m using the 30Mar10 version of lammps. I have a problem.

I got errors “Failed to reallocate %d bytes for array %s” when I was running an atomic system with more than 10 milllion atoms on 128 and 256 CPUs.

The lammps manual suggests it is a memory problem:
"Your LAMMPS simulation has run out of memory. You need to run a smaller simulation or on more processors. "

What surprised me is that the above system can be run normally on 64 CPUs. And the output memory usage information is as follows:
“Memory usage per processor = 195.239 Mbytes”

The actual situation is opposite to the suggestion from the manual. Why?


Haofei Zhou

If you can run on 64 procs with 195 Mb/proc, you should not
run out of memory on 128 procs. Something else must be going
on. How big the the allocation is says failed?