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lammps/src/SNAP/compute_snad_atom.cpp
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compute_snad_atom.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 "sna.h"
#include "string.h"
#include "stdlib.h"
#include "compute_snad_atom.h"
#include "atom.h"
#include "update.h"
#include "modify.h"
#include "neighbor.h"
#include "neigh_list.h"
#include "neigh_request.h"
#include "force.h"
#include "pair.h"
#include "comm.h"
#include "memory.h"
#include "error.h"
#include "openmp_snap.h"
using namespace LAMMPS_NS;
ComputeSNADAtom::ComputeSNADAtom(LAMMPS *lmp, int narg, char **arg) :
Compute(lmp, narg, arg)
{
double rfac0, rmin0;
int twojmax, switchflag;
radelem = NULL;
wjelem = NULL;
int ntypes = atom->ntypes;
int nargmin = 6+2*ntypes;
if (narg < nargmin) error->all(FLERR,"Illegal compute snad/atom command");
// default values
diagonalstyle = 0;
rmin0 = 0.0;
switchflag = 1;
// process required arguments
memory->create(radelem,ntypes+1,"sna/atom:radelem"); // offset by 1 to match up with types
memory->create(wjelem,ntypes+1,"sna/atom:wjelem");
rcutfac = atof(arg[3]);
rfac0 = atof(arg[4]);
twojmax = atoi(arg[5]);
for(int i = 0; i < ntypes; i++)
radelem[i+1] = atof(arg[6+i]);
for(int i = 0; i < ntypes; i++)
wjelem[i+1] = atof(arg[6+ntypes+i]);
// construct cutsq
double cut;
memory->create(cutsq,ntypes+1,ntypes+1,"sna/atom:cutsq");
for(int i = 1; i <= ntypes; i++) {
cut = 2.0*radelem[i]*rcutfac;
cutsq[i][i] = cut*cut;
for(int j = i+1; j <= ntypes; j++) {
cut = (radelem[i]+radelem[j])*rcutfac;
cutsq[i][j] = cutsq[j][i] = cut*cut;
}
}
// process optional args
int iarg = nargmin;
while (iarg < narg) {
if (strcmp(arg[iarg],"diagonal") == 0) {
if (iarg+2 > narg)
error->all(FLERR,"Illegal compute snad/atom command");
diagonalstyle = atof(arg[iarg+1]);
if (diagonalstyle < 0 || diagonalstyle > 3)
error->all(FLERR,"Illegal compute snad/atom command");
iarg += 2;
} else if (strcmp(arg[iarg],"rmin0") == 0) {
if (iarg+2 > narg)
error->all(FLERR,"Illegal compute snad/atom command");
rmin0 = atof(arg[iarg+1]);
iarg += 2;
} else if (strcmp(arg[iarg],"switchflag") == 0) {
if (iarg+2 > narg)
error->all(FLERR,"Illegal compute snad/atom command");
switchflag = atoi(arg[iarg+1]);
iarg += 2;
} else error->all(FLERR,"Illegal compute snad/atom command");
}
snaptr = new SNA*[comm->nthreads];
#if defined(_OPENMP)
#pragma omp parallel default(none) shared(lmp,rfac0,twojmax,rmin0,switchflag)
#endif
{
int tid = omp_get_thread_num();
// always unset use_shared_arrays since it does not work with computes
snaptr[tid] = new SNA(lmp,rfac0,twojmax,diagonalstyle,
0 /*use_shared_arrays*/, rmin0,switchflag);
}
ncoeff = snaptr[0]->ncoeff;
peratom_flag = 1;
size_peratom_cols = 3*ncoeff*atom->ntypes;
comm_reverse = size_peratom_cols;
nmax = 0;
njmax = 0;
snad = NULL;
}
/* ---------------------------------------------------------------------- */
ComputeSNADAtom::~ComputeSNADAtom()
{
memory->destroy(snad);
memory->destroy(radelem);
memory->destroy(wjelem);
memory->destroy(cutsq);
delete [] snaptr;
}
/* ---------------------------------------------------------------------- */
void ComputeSNADAtom::init()
{
if (force->pair == NULL)
error->all(FLERR,"Compute snad/atom requires a pair style be defined");
// TODO: Not sure what to do with this error check since cutoff radius is not
// a single number
//if (sqrt(cutsq) > force->pair->cutforce)
//error->all(FLERR,"Compute snad/atom cutoff is longer than pairwise cutoff");
// need an occasional full neighbor list
int irequest = neighbor->request((void *) this);
neighbor->requests[irequest]->pair = 0;
neighbor->requests[irequest]->compute = 1;
neighbor->requests[irequest]->half = 0;
neighbor->requests[irequest]->full = 1;
neighbor->requests[irequest]->occasional = 1;
int count = 0;
for (int i = 0; i < modify->ncompute; i++)
if (strcmp(modify->compute[i]->style,"snad/atom") == 0) count++;
if (count > 1 && comm->me == 0)
error->warning(FLERR,"More than one compute snad/atom");
#if defined(_OPENMP)
#pragma omp parallel default(none)
#endif
{
int tid = omp_get_thread_num();
snaptr[tid]->init();
}
}
/* ---------------------------------------------------------------------- */
void ComputeSNADAtom::init_list(int id, NeighList *ptr)
{
list = ptr;
}
/* ---------------------------------------------------------------------- */
void ComputeSNADAtom::compute_peratom()
{
int ntotal = atom->nlocal + atom->nghost;
invoked_peratom = update->ntimestep;
// grow snad array if necessary
if (ntotal > nmax) {
memory->destroy(snad);
nmax = atom->nmax;
memory->create(snad,nmax,size_peratom_cols,
"snad/atom:snad");
array_atom = snad;
}
// clear local array
for (int i = 0; i < ntotal; i++)
for (int icoeff = 0; icoeff < size_peratom_cols; icoeff++) {
snad[i][icoeff] = 0.0;
}
// invoke full neighbor list (will copy or build if necessary)
neighbor->build_one(list);
const int inum = list->inum;
const int* const ilist = list->ilist;
const int* const numneigh = list->numneigh;
int** const firstneigh = list->firstneigh;
int * const type = atom->type;
// compute sna derivatives for each atom in group
// use full neighbor list to count atoms less than cutoff
double** const x = atom->x;
const int* const mask = atom->mask;
#if defined(_OPENMP)
#pragma omp parallel for default(none)
#endif
for (int ii = 0; ii < inum; ii++) {
const int tid = omp_get_thread_num();
const int i = ilist[ii];
if (mask[i] & groupbit) {
const double xtmp = x[i][0];
const double ytmp = x[i][1];
const double ztmp = x[i][2];
const int itype = type[i];
const double radi = radelem[itype];
const int* const jlist = firstneigh[i];
const int jnum = numneigh[i];
const int typeoffset = 3*ncoeff*(atom->type[i]-1);
// insure rij, inside, and typej are of size jnum
snaptr[tid]->grow_rij(jnum);
// rij[][3] = displacements between atom I and those neighbors
// inside = indices of neighbors of I within cutoff
// typej = types of neighbors of I within cutoff
// note Rij sign convention => dU/dRij = dU/dRj = -dU/dRi
int ninside = 0;
for (int jj = 0; jj < jnum; jj++) {
int j = jlist[jj];
j &= NEIGHMASK;
const double delx = x[j][0] - xtmp;
const double dely = x[j][1] - ytmp;
const double delz = x[j][2] - ztmp;
const double rsq = delx*delx + dely*dely + delz*delz;
int jtype = type[j];
if (rsq < cutsq[itype][jtype]&&rsq>1e-20) {
snaptr[tid]->rij[ninside][0] = delx;
snaptr[tid]->rij[ninside][1] = dely;
snaptr[tid]->rij[ninside][2] = delz;
snaptr[tid]->inside[ninside] = j;
snaptr[tid]->wj[ninside] = wjelem[jtype];
snaptr[tid]->rcutij[ninside] = (radi+radelem[jtype])*rcutfac;
ninside++;
}
}
snaptr[tid]->compute_ui(ninside);
snaptr[tid]->compute_zi();
for (int jj = 0; jj < ninside; jj++) {
const int j = snaptr[tid]->inside[jj];
snaptr[tid]->compute_duidrj(snaptr[tid]->rij[jj],
snaptr[tid]->wj[jj],
snaptr[tid]->rcutij[jj]);
snaptr[tid]->compute_dbidrj();
snaptr[tid]->copy_dbi2dbvec();
// Accumulate -dBi/dRi, -dBi/dRj
double *snadi = snad[i]+typeoffset;
double *snadj = snad[j]+typeoffset;
for (int icoeff = 0; icoeff < ncoeff; icoeff++) {
snadi[icoeff] += snaptr[tid]->dbvec[icoeff][0];
snadi[icoeff+ncoeff] += snaptr[tid]->dbvec[icoeff][1];
snadi[icoeff+2*ncoeff] += snaptr[tid]->dbvec[icoeff][2];
snadj[icoeff] -= snaptr[tid]->dbvec[icoeff][0];
snadj[icoeff+ncoeff] -= snaptr[tid]->dbvec[icoeff][1];
snadj[icoeff+2*ncoeff] -= snaptr[tid]->dbvec[icoeff][2];
}
}
}
}
// communicate snad contributions between neighbor procs
comm->reverse_comm_compute(this);
}
/* ---------------------------------------------------------------------- */
int ComputeSNADAtom::pack_reverse_comm(int n, int first, double *buf)
{
int i,m,last,icoeff;
m = 0;
last = first + n;
for (i = first; i < last; i++)
for (icoeff = 0; icoeff < size_peratom_cols; icoeff++)
buf[m++] = snad[i][icoeff];
return comm_reverse;
}
/* ---------------------------------------------------------------------- */
void ComputeSNADAtom::unpack_reverse_comm(int n, int *list, double *buf)
{
int i,j,m,icoeff;
m = 0;
for (i = 0; i < n; i++) {
j = list[i];
for (icoeff = 0; icoeff < size_peratom_cols; icoeff++)
snad[j][icoeff] += buf[m++];
}
}
/* ----------------------------------------------------------------------
memory usage
------------------------------------------------------------------------- */
double ComputeSNADAtom::memory_usage()
{
double bytes = nmax*size_peratom_cols * sizeof(double);
bytes += 3*njmax*sizeof(double);
bytes += njmax*sizeof(int);
bytes += ncoeff*3;
bytes += snaptr[0]->memory_usage()*comm->nthreads;
return bytes;
}
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