Files
lammps/src/compute_com_chunk.cpp

151 lines
4.3 KiB
C++

/* ----------------------------------------------------------------------
LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
https://www.lammps.org/, Sandia National Laboratories
LAMMPS development team: developers@lammps.org
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 "compute_com_chunk.h"
#include "atom.h"
#include "compute_chunk_atom.h"
#include "domain.h"
#include "error.h"
#include "memory.h"
using namespace LAMMPS_NS;
enum { ONCE, NFREQ, EVERY };
/* ---------------------------------------------------------------------- */
ComputeCOMChunk::ComputeCOMChunk(LAMMPS *lmp, int narg, char **arg) :
ComputeChunk(lmp, narg, arg), masstotal(nullptr), massproc(nullptr), com(nullptr),
comall(nullptr)
{
if (narg != 4) error->all(FLERR, "Illegal compute com/chunk command");
array_flag = 1;
size_array_cols = 3;
size_array_rows = 0;
size_array_rows_variable = 1;
extarray = 0;
ComputeCOMChunk::init();
ComputeCOMChunk::allocate();
}
/* ---------------------------------------------------------------------- */
ComputeCOMChunk::~ComputeCOMChunk()
{
memory->destroy(massproc);
memory->destroy(masstotal);
memory->destroy(com);
memory->destroy(comall);
}
/* ---------------------------------------------------------------------- */
void ComputeCOMChunk::setup()
{
// one-time calculation of per-chunk mass
// done in setup, so that ComputeChunkAtom::setup() is already called
if (firstflag && cchunk->idsflag == ONCE) {
compute_array();
firstflag = massneed = 0;
}
}
/* ---------------------------------------------------------------------- */
void ComputeCOMChunk::compute_array()
{
int index;
double massone;
double unwrap[3];
ComputeChunk::compute_array();
int *ichunk = cchunk->ichunk;
// zero local per-chunk values
for (int i = 0; i < nchunk; i++) com[i][0] = com[i][1] = com[i][2] = 0.0;
if (massneed)
for (int i = 0; i < nchunk; i++) massproc[i] = 0.0;
// compute COM for each chunk
double **x = atom->x;
int *mask = atom->mask;
int *type = atom->type;
imageint *image = atom->image;
double *mass = atom->mass;
double *rmass = atom->rmass;
int nlocal = atom->nlocal;
for (int i = 0; i < nlocal; i++)
if (mask[i] & groupbit) {
index = ichunk[i] - 1;
if (index < 0) continue;
if (rmass)
massone = rmass[i];
else
massone = mass[type[i]];
domain->unmap(x[i], image[i], unwrap);
com[index][0] += unwrap[0] * massone;
com[index][1] += unwrap[1] * massone;
com[index][2] += unwrap[2] * massone;
if (massneed) massproc[index] += massone;
}
MPI_Allreduce(&com[0][0], &comall[0][0], 3 * nchunk, MPI_DOUBLE, MPI_SUM, world);
if (massneed) MPI_Allreduce(massproc, masstotal, nchunk, MPI_DOUBLE, MPI_SUM, world);
for (int i = 0; i < nchunk; i++) {
if (masstotal[i] > 0.0) {
comall[i][0] /= masstotal[i];
comall[i][1] /= masstotal[i];
comall[i][2] /= masstotal[i];
} else
comall[i][0] = comall[i][1] = comall[i][2] = 0.0;
}
}
/* ----------------------------------------------------------------------
free and reallocate per-chunk arrays
------------------------------------------------------------------------- */
void ComputeCOMChunk::allocate()
{
memory->destroy(massproc);
memory->destroy(masstotal);
memory->destroy(com);
memory->destroy(comall);
maxchunk = nchunk;
memory->create(massproc, maxchunk, "com/chunk:massproc");
memory->create(masstotal, maxchunk, "com/chunk:masstotal");
memory->create(com, maxchunk, 3, "com/chunk:com");
memory->create(comall, maxchunk, 3, "com/chunk:comall");
array = comall;
}
/* ----------------------------------------------------------------------
memory usage of local data
------------------------------------------------------------------------- */
double ComputeCOMChunk::memory_usage()
{
double bytes = ComputeChunk::memory_usage();
bytes += (bigint) maxchunk * 2 * sizeof(double);
bytes += (double) maxchunk * 2 * 3 * sizeof(double);
return bytes;
}