note: so just want to avoid that numeric probem?

------------------------------------------------------------------------- */

/* ----------------------------------------------------------------------

   atom to processor assignments have changed,

     so acquire ghost bodies and setup atom2body

   remap xcm of each rigid body back into periodic simulation box

   done during pre_neighbor so will be after call to pbc()

     and after fix_deform::pre_exchange() may have flipped box

   use domain->remap() in case xcm is far away from box

     due to 1st definition of rigid body or due to box flip

   if don't do this, then atoms of a body which drifts far away

     from a triclinic box will be remapped back into box

     with huge displacements when the box tilt changes via set_x()

   adjust image flag of body and image flags of all atoms in body

------------------------------------------------------------------------- */

void FixRigidSmall::pre_neighbor()

{

  // acquire ghost bodies via forward comm

  // check for regrow of vatom

  // must be done whether per-atom virial is accumulated on this step or not

  //   b/c this is only time grow_array() may be called

  // since vatom is calculated before and after atom migration

  // need to regrow b/c vatom is calculated before and after atom migration

  if (nmax > maxvatom) {

    maxvatom = atom->nmax;