Note on GCMC and dump sorted by atom id

Where exactly am I supposed to define LAMMPS_QSORT and
how can I be sure to have the qsort-sorting activated?

For now I compiled LAMMPS (single thread) with
     CCFLAGS = -g -O3 -DLAMMPS_QSORT
*and*
     LMP_INC = -DLAMMPS_QSORT -DLAMMPS_GZIP ...

Is there a quick test to see if qsort is being used?

BTW: I got a toy example showing the error within 3h on
my desktop machine (will post after soting out the qsort
issue).

M.

This sounds like you have found a hard to reproduce bug with the sorting
method. I cannot easily check the source right now, but you should be
able to revert to a (slower) sort method when compiling with
-DLAMMPS_QSORT or something similar.

Please let me know if that makes a difference.

Where exactly am I supposed to define LAMMPS_QSORT and
how can I be sure to have the qsort-sorting activated?

i just checked with the source code. i have misremembered the exact name of the define. it has to be -DLMP_QSORT

For now I compiled LAMMPS (single thread) with
CCFLAGS = -g -O3 -DLAMMPS_QSORT
and
LMP_INC = -DLAMMPS_QSORT -DLAMMPS_GZIP …

just adding -DLMP_QSORT to LMP_INC should suffice.

Is there a quick test to see if qsort is being used?

nm lmp_ | grep qsort

on my machine i get with -DLMP_QSORT enabled.

nm lmp_mpi | grep qsort U [email protected]@GLIBC_2.2.5

and without:

nm lmp_mpi | grep qsort

axel.