Files
lammps/src/LEPTON/pair_lepton.cpp
2024-02-28 15:37:13 -05:00

459 lines
14 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.
------------------------------------------------------------------------- */
/* ----------------------------------------------------------------------
Contributing author: Axel Kohlmeyer (Temple U)
------------------------------------------------------------------------- */
#include "pair_lepton.h"
#include "atom.h"
#include "comm.h"
#include "error.h"
#include "force.h"
#include "memory.h"
#include "neigh_list.h"
#include "Lepton.h"
#include "lepton_utils.h"
#include <cmath>
#include <exception>
#include <map>
using namespace LAMMPS_NS;
/* ---------------------------------------------------------------------- */
PairLepton::PairLepton(LAMMPS *lmp) :
Pair(lmp), cut(nullptr), type2expression(nullptr), offset(nullptr)
{
respa_enable = 0;
single_enable = 1;
writedata = 1;
restartinfo = 1;
reinitflag = 0;
cut_global = 0.0;
centroidstressflag = CENTROID_SAME;
functions["zbl"] = new Lepton::ZBLFunction(force->qqr2e, force->angstrom, force->qelectron);
}
/* ---------------------------------------------------------------------- */
PairLepton::~PairLepton()
{
for (auto &f : functions) delete f.second;
if (allocated) {
memory->destroy(cut);
memory->destroy(cutsq);
memory->destroy(setflag);
memory->destroy(type2expression);
memory->destroy(offset);
}
}
/* ---------------------------------------------------------------------- */
void PairLepton::compute(int eflag, int vflag)
{
ev_init(eflag, vflag);
if (evflag) {
if (eflag) {
if (force->newton_pair)
eval<1, 1, 1>();
else
eval<1, 1, 0>();
} else {
if (force->newton_pair)
eval<1, 0, 1>();
else
eval<1, 0, 0>();
}
} else {
if (force->newton_pair)
eval<0, 0, 1>();
else
eval<0, 0, 0>();
}
if (vflag_fdotr) virial_fdotr_compute();
}
/* ---------------------------------------------------------------------- */
template <int EVFLAG, int EFLAG, int NEWTON_PAIR> void PairLepton::eval()
{
const double *const *const x = atom->x;
double *const *const f = atom->f;
const int *const type = atom->type;
const int nlocal = atom->nlocal;
const double *const special_lj = force->special_lj;
const int inum = list->inum;
const int *const ilist = list->ilist;
const int *const numneigh = list->numneigh;
const int *const *const firstneigh = list->firstneigh;
double fxtmp, fytmp, fztmp;
std::vector<Lepton::CompiledExpression> pairforce;
std::vector<Lepton::CompiledExpression> pairpot;
std::vector<bool> has_ref;
try {
for (const auto &expr : expressions) {
auto parsed = Lepton::Parser::parse(LeptonUtils::substitute(expr, lmp), functions);
pairforce.emplace_back(parsed.differentiate("r").createCompiledExpression());
has_ref.push_back(true);
try {
pairforce.back().getVariableReference("r");
} catch (Lepton::Exception &) {
has_ref.back() = false;
}
if (EFLAG) pairpot.emplace_back(parsed.createCompiledExpression());
}
} catch (std::exception &e) {
error->all(FLERR, e.what());
}
// loop over neighbors of my atoms
for (int ii = 0; ii < inum; ii++) {
const int i = ilist[ii];
const double xtmp = x[i][0];
const double ytmp = x[i][1];
const double ztmp = x[i][2];
const int itype = type[i];
const int *jlist = firstneigh[i];
const int jnum = numneigh[i];
fxtmp = fytmp = fztmp = 0.0;
for (int jj = 0; jj < jnum; jj++) {
int j = jlist[jj];
const double factor_lj = special_lj[sbmask(j)];
j &= NEIGHMASK;
const int jtype = type[j];
const double delx = xtmp - x[j][0];
const double dely = ytmp - x[j][1];
const double delz = ztmp - x[j][2];
const double rsq = delx * delx + dely * dely + delz * delz;
if (rsq < cutsq[itype][jtype]) {
const double r = sqrt(rsq);
const int idx = type2expression[itype][jtype];
if (has_ref[idx]) pairforce[idx].getVariableReference("r") = r;
const double fpair = -pairforce[idx].evaluate() / r * factor_lj;
fxtmp += delx * fpair;
fytmp += dely * fpair;
fztmp += delz * fpair;
if (NEWTON_PAIR || (j < nlocal)) {
f[j][0] -= delx * fpair;
f[j][1] -= dely * fpair;
f[j][2] -= delz * fpair;
}
double evdwl = 0.0;
if (EFLAG) {
try {
pairpot[idx].getVariableReference("r") = r;
} catch (Lepton::Exception &) {
; // ignore -> constant potential
}
evdwl = pairpot[idx].evaluate() - offset[itype][jtype];
evdwl *= factor_lj;
}
if (EVFLAG) ev_tally(i, j, nlocal, NEWTON_PAIR, evdwl, 0.0, fpair, delx, dely, delz);
}
}
f[i][0] += fxtmp;
f[i][1] += fytmp;
f[i][2] += fztmp;
}
}
/* ----------------------------------------------------------------------
allocate all arrays
------------------------------------------------------------------------- */
void PairLepton::allocate()
{
allocated = 1;
int np1 = atom->ntypes + 1;
memory->create(setflag, np1, np1, "pair:setflag");
for (int i = 1; i < np1; i++)
for (int j = i; j < np1; j++) setflag[i][j] = 0;
memory->create(cut, np1, np1, "pair:cut");
memory->create(cutsq, np1, np1, "pair:cutsq");
memory->create(type2expression, np1, np1, "pair:type2expression");
memory->create(offset, np1, np1, "pair:offset");
}
/* ----------------------------------------------------------------------
global settings
------------------------------------------------------------------------- */
void PairLepton::settings(int narg, char **arg)
{
if (narg != 1) error->all(FLERR, "Incorrect number of arguments for pair_style lepton command");
cut_global = utils::numeric(FLERR, arg[0], false, lmp);
}
/* ----------------------------------------------------------------------
set coeffs for all type pairs
------------------------------------------------------------------------- */
void PairLepton::coeff(int narg, char **arg)
{
if (narg < 3 || narg > 4) error->all(FLERR, "Incorrect number of args for pair coefficients");
if (!allocated) allocate();
int ilo, ihi, jlo, jhi;
utils::bounds(FLERR, arg[0], 1, atom->ntypes, ilo, ihi, error);
utils::bounds(FLERR, arg[1], 1, atom->ntypes, jlo, jhi, error);
double cut_one = cut_global;
if (narg == 4) {
if (pppmflag || ewaldflag || msmflag || dispersionflag || tip4pflag) {
error->all(FLERR, "Only a global cutoff is allowed with Kspace compatibility enabled");
} else {
cut_one = utils::numeric(FLERR, arg[3], false, lmp);
}
}
// remove whitespace and quotes from expression string and then
// check if the expression can be parsed and evaluated without error
auto exp_one = LeptonUtils::condense(arg[2]);
try {
auto parsed = Lepton::Parser::parse(LeptonUtils::substitute(exp_one, lmp), functions);
auto pairforce = parsed.differentiate("r").createCompiledExpression();
auto pairpot = parsed.createCompiledExpression();
try {
pairpot.getVariableReference("r") = 1.0;
pairforce.getVariableReference("r") = 1.0;
} catch (Lepton::Exception &) {
; // ignore -> constant potential or force
}
pairpot.evaluate();
pairforce.evaluate();
} catch (std::exception &e) {
error->all(FLERR, e.what());
}
std::size_t idx = 0;
for (const auto &exp : expressions) {
if (exp == exp_one) break;
++idx;
}
// not found, add to list
if ((expressions.size() == 0) || (idx == expressions.size())) expressions.push_back(exp_one);
int count = 0;
for (int i = ilo; i <= ihi; i++) {
for (int j = MAX(jlo, i); j <= jhi; j++) {
cut[i][j] = cut_one;
setflag[i][j] = 1;
type2expression[i][j] = idx;
count++;
}
}
if (count == 0) error->all(FLERR, "Incorrect args for pair coefficients");
}
/* ---------------------------------------------------------------------- */
double PairLepton::init_one(int i, int j)
{
if (setflag[i][j] == 0) error->all(FLERR, "All pair coeffs are not set");
offset[i][j] = 0.0;
if (offset_flag) {
try {
auto expr = LeptonUtils::substitute(expressions[type2expression[i][j]], lmp);
auto pairpot = Lepton::Parser::parse(expr, functions).createCompiledExpression();
try {
pairpot.getVariableReference("r") = cut[i][j];
} catch (Lepton::Exception &) {
; // ignore -> constant potential
}
offset[i][j] = pairpot.evaluate();
} catch (std::exception &) {
}
}
cut[j][i] = cut[i][j];
type2expression[j][i] = type2expression[i][j];
offset[j][i] = offset[i][j];
return cut[i][j];
}
/* ----------------------------------------------------------------------
proc 0 writes to restart file
------------------------------------------------------------------------- */
void PairLepton::write_restart(FILE *fp)
{
write_restart_settings(fp);
for (int i = 1; i <= atom->ntypes; i++)
for (int j = i; j <= atom->ntypes; j++) {
fwrite(&setflag[i][j], sizeof(int), 1, fp);
if (setflag[i][j]) {
fwrite(&cut[i][j], sizeof(double), 1, fp);
fwrite(&type2expression[i][j], sizeof(int), 1, fp);
}
}
int num = expressions.size();
int maxlen = 0;
for (const auto &exp : expressions) maxlen = MAX(maxlen, (int) exp.size());
++maxlen;
fwrite(&num, sizeof(int), 1, fp);
fwrite(&maxlen, sizeof(int), 1, fp);
for (const auto &exp : expressions) {
int n = exp.size() + 1;
fwrite(&n, sizeof(int), 1, fp);
fwrite(exp.c_str(), sizeof(char), n, fp);
}
}
/* ----------------------------------------------------------------------
proc 0 reads from restart file, bcasts
------------------------------------------------------------------------- */
void PairLepton::read_restart(FILE *fp)
{
read_restart_settings(fp);
allocate();
expressions.clear();
const int me = comm->me;
for (int i = 1; i <= atom->ntypes; i++)
for (int j = i; j <= atom->ntypes; j++) {
if (me == 0) utils::sfread(FLERR, &setflag[i][j], sizeof(int), 1, fp, nullptr, error);
MPI_Bcast(&setflag[i][j], 1, MPI_INT, 0, world);
if (setflag[i][j]) {
if (me == 0) {
utils::sfread(FLERR, &cut[i][j], sizeof(double), 1, fp, nullptr, error);
utils::sfread(FLERR, &type2expression[i][j], sizeof(int), 1, fp, nullptr, error);
}
MPI_Bcast(&cut[i][j], 1, MPI_DOUBLE, 0, world);
MPI_Bcast(&type2expression[i][j], 1, MPI_INT, 0, world);
}
}
int num, maxlen, len;
if (me == 0) {
utils::sfread(FLERR, &num, sizeof(int), 1, fp, nullptr, error);
utils::sfread(FLERR, &maxlen, sizeof(int), 1, fp, nullptr, error);
}
MPI_Bcast(&num, 1, MPI_INT, 0, world);
MPI_Bcast(&maxlen, 1, MPI_INT, 0, world);
char *buf = new char[maxlen];
for (int i = 0; i < num; ++i) {
if (me == 0) {
utils::sfread(FLERR, &len, sizeof(int), 1, fp, nullptr, error);
utils::sfread(FLERR, buf, sizeof(char), len, fp, nullptr, error);
}
MPI_Bcast(buf, maxlen, MPI_CHAR, 0, world);
expressions.emplace_back(buf);
}
delete[] buf;
}
/* ----------------------------------------------------------------------
proc 0 writes to restart file
------------------------------------------------------------------------- */
void PairLepton::write_restart_settings(FILE *fp)
{
fwrite(&cut_global, sizeof(double), 1, fp);
fwrite(&offset_flag, sizeof(int), 1, fp);
}
/* ----------------------------------------------------------------------
proc 0 reads from restart file, bcasts
------------------------------------------------------------------------- */
void PairLepton::read_restart_settings(FILE *fp)
{
if (comm->me == 0) {
utils::sfread(FLERR, &cut_global, sizeof(double), 1, fp, nullptr, error);
utils::sfread(FLERR, &offset_flag, sizeof(int), 1, fp, nullptr, error);
}
MPI_Bcast(&cut_global, 1, MPI_DOUBLE, 0, world);
MPI_Bcast(&offset_flag, 1, MPI_INT, 0, world);
}
/* ----------------------------------------------------------------------
proc 0 writes to data file
------------------------------------------------------------------------- */
void PairLepton::write_data(FILE *fp)
{
if (pppmflag || ewaldflag || msmflag || dispersionflag || tip4pflag) {
for (int i = 1; i <= atom->ntypes; i++)
fprintf(fp, "%d %s\n", i, expressions[type2expression[i][i]].c_str());
} else {
for (int i = 1; i <= atom->ntypes; i++)
fprintf(fp, "%d %s %g\n", i, expressions[type2expression[i][i]].c_str(), cut[i][i]);
}
}
/* ----------------------------------------------------------------------
proc 0 writes all pairs to data file
------------------------------------------------------------------------- */
void PairLepton::write_data_all(FILE *fp)
{
if (pppmflag || ewaldflag || msmflag || dispersionflag || tip4pflag) {
for (int i = 1; i <= atom->ntypes; i++)
for (int j = i; j <= atom->ntypes; j++)
fprintf(fp, "%d %d %s\n", i, j, expressions[type2expression[i][j]].c_str());
} else {
for (int i = 1; i <= atom->ntypes; i++)
for (int j = i; j <= atom->ntypes; j++)
fprintf(fp, "%d %d %s %g\n", i, j, expressions[type2expression[i][j]].c_str(), cut[i][j]);
}
}
/* ---------------------------------------------------------------------- */
double PairLepton::single(int /* i */, int /* j */, int itype, int jtype, double rsq,
double /* factor_coul */, double factor_lj, double &fforce)
{
const auto &expr = expressions[type2expression[itype][jtype]];
auto parsed = Lepton::Parser::parse(LeptonUtils::substitute(expr, lmp), functions);
auto pairpot = parsed.createCompiledExpression();
auto pairforce = parsed.differentiate("r").createCompiledExpression();
const double r = sqrt(rsq);
try {
pairpot.getVariableReference("r") = r;
pairforce.getVariableReference("r") = r;
} catch (Lepton::Exception &) {
; // ignore -> constant potential or force
}
fforce = -pairforce.evaluate() / r * factor_lj;
return (pairpot.evaluate() - offset[itype][jtype]) * factor_lj;
}