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imbalance_neigh.cpp
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Thu, Nov 7, 19:14

imbalance_neigh.cpp
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/* ----------------------------------------------------------------------
LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
http://lammps.sandia.gov, Sandia National Laboratories
Steve Plimpton, sjplimp@sandia.gov
Copyright (2003) Sandia Corporation. Under the terms of Contract
DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
certain rights in this software. This software is distributed under
the GNU General Public License.
See the README file in the top-level LAMMPS directory.
------------------------------------------------------------------------- */
#include <mpi.h>
#include "imbalance_neigh.h"
#include "atom.h"
#include "comm.h"
#include "force.h"
#include "neighbor.h"
#include "neigh_request.h"
#include "neigh_list.h"
#include "error.h"
using namespace LAMMPS_NS;
/* -------------------------------------------------------------------- */
ImbalanceNeigh::ImbalanceNeigh(LAMMPS *lmp) : Imbalance(lmp)
{
did_warn = 0;
}
/* -------------------------------------------------------------------- */
int ImbalanceNeigh::options(int narg, char **arg)
{
if (narg < 1) error->all(FLERR,"Illegal balance weight command");
factor = force->numeric(FLERR,arg[0]);
if (factor < 0.0) error->all(FLERR,"Illegal balance weight command");
return 1;
}
/* -------------------------------------------------------------------- */
void ImbalanceNeigh::compute(double *weight)
{
int req;
if (factor == 0.0) return;
// find suitable neighbor list
// we can only make use of certain (conventional) neighbor lists
for (req = 0; req < neighbor->old_nrequest; ++req) {
if ((neighbor->old_requests[req]->half ||
neighbor->old_requests[req]->gran ||
neighbor->old_requests[req]->respaouter ||
neighbor->old_requests[req]->half_from_full) &&
neighbor->old_requests[req]->skip == 0 &&
neighbor->lists[req] && neighbor->lists[req]->numneigh) break;
}
if (req >= neighbor->old_nrequest || neighbor->ago < 0) {
if (comm->me == 0 && !did_warn)
error->warning(FLERR,"No suitable neighbor list found. "
"Neighbor weighted balancing skipped");
did_warn = 1;
return;
}
NeighList *list = neighbor->lists[req];
bigint neighsum = 0;
const int inum = list->inum;
const int * const ilist = list->ilist;
const int * const numneigh = list->numneigh;
// first pass: get local number of neighbors
for (int i = 0; i < inum; ++i) neighsum += numneigh[ilist[i]];
double allatoms = static_cast <double>(atom->natoms);
if (allatoms == 0.0) allatoms = 1.0;
double allavg;
double myavg = static_cast<double>(neighsum)/allatoms;
MPI_Allreduce(&myavg,&allavg,1,MPI_DOUBLE,MPI_SUM,world);
// second pass: compute and apply weights
double scale = 1.0/allavg;
for (int ii = 0; ii < inum; ++ii) {
const int i = ilist[ii];
weight[i] *= (1.0-factor) + factor*scale*numneigh[i];
}
}
/* -------------------------------------------------------------------- */
void ImbalanceNeigh::info(FILE *fp)
{
fprintf(fp," neigh weight factor: %g\n",factor);
}

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