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lammps/src/USER-INTEL/angle_charmm_intel.cpp
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angle_charmm_intel.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.
------------------------------------------------------------------------- */
/* ----------------------------------------------------------------------
Contributing author: W. Michael Brown (Intel)
------------------------------------------------------------------------- */
#include <math.h>
#include <stdlib.h>
#include "angle_charmm_intel.h"
#include "atom.h"
#include "neighbor.h"
#include "domain.h"
#include "comm.h"
#include "force.h"
#include "math_const.h"
#include "memory.h"
#include "suffix.h"
#include "error.h"
using namespace LAMMPS_NS;
using namespace MathConst;
#define SMALL2 (flt_t)0.000001
#define INVSMALL (flt_t)1000.0
typedef struct { int a,b,c,t; } int4_t;
/* ---------------------------------------------------------------------- */
AngleCharmmIntel::AngleCharmmIntel(LAMMPS *lmp) : AngleCharmm(lmp)
{
suffix_flag |= Suffix::INTEL;
}
/* ---------------------------------------------------------------------- */
AngleCharmmIntel::~AngleCharmmIntel()
{
}
/* ---------------------------------------------------------------------- */
void AngleCharmmIntel::compute(int eflag, int vflag)
{
#ifdef _LMP_INTEL_OFFLOAD
if (_use_base) {
AngleCharmm::compute(eflag, vflag);
return;
}
#endif
if (fix->precision() == FixIntel::PREC_MODE_MIXED)
compute<float,double>(eflag, vflag, fix->get_mixed_buffers(),
force_const_single);
else if (fix->precision() == FixIntel::PREC_MODE_DOUBLE)
compute<double,double>(eflag, vflag, fix->get_double_buffers(),
force_const_double);
else
compute<float,float>(eflag, vflag, fix->get_single_buffers(),
force_const_single);
}
/* ---------------------------------------------------------------------- */
template <class flt_t, class acc_t>
void AngleCharmmIntel::compute(int eflag, int vflag,
IntelBuffers<flt_t,acc_t> *buffers,
const ForceConst<flt_t> &fc)
{
if (eflag || vflag) ev_setup(eflag,vflag);
else evflag = 0;
if (evflag) {
if (eflag) {
if (force->newton_bond)
eval<1,1,1>(vflag, buffers, fc);
else
eval<1,1,0>(vflag, buffers, fc);
} else {
if (force->newton_bond)
eval<1,0,1>(vflag, buffers, fc);
else
eval<1,0,0>(vflag, buffers, fc);
}
} else {
if (force->newton_bond)
eval<0,0,1>(vflag, buffers, fc);
else
eval<0,0,0>(vflag, buffers, fc);
}
}
/* ---------------------------------------------------------------------- */
template <int EVFLAG, int EFLAG, int NEWTON_BOND, class flt_t, class acc_t>
void AngleCharmmIntel::eval(const int vflag,
IntelBuffers<flt_t,acc_t> *buffers,
const ForceConst<flt_t> &fc)
{
const int inum = neighbor->nanglelist;
if (inum == 0) return;
ATOM_T * _noalias const x = buffers->get_x(0);
const int nlocal = atom->nlocal;
const int nall = nlocal + atom->nghost;
int f_stride;
if (NEWTON_BOND) f_stride = buffers->get_stride(nall);
else f_stride = buffers->get_stride(nlocal);
int tc;
FORCE_T * _noalias f_start;
acc_t * _noalias ev_global;
IP_PRE_get_buffers(0, buffers, fix, tc, f_start, ev_global);
const int nthreads = tc;
acc_t oeangle, ov0, ov1, ov2, ov3, ov4, ov5;
if (EVFLAG) {
if (EFLAG)
oeangle = (acc_t)0.0;
if (vflag) {
ov0 = ov1 = ov2 = ov3 = ov4 = ov5 = (acc_t)0.0;
}
}
#if defined(_OPENMP)
#pragma omp parallel default(none) \
shared(f_start,f_stride,fc) \
reduction(+:oeangle,ov0,ov1,ov2,ov3,ov4,ov5)
#endif
{
int nfrom, nto, tid;
IP_PRE_omp_range_id(nfrom, nto, tid, inum, nthreads);
FORCE_T * _noalias const f = f_start + (tid * f_stride);
if (fix->need_zero(tid))
memset(f, 0, f_stride * sizeof(FORCE_T));
const int4_t * _noalias const anglelist =
(int4_t *) neighbor->anglelist[0];
for (int n = nfrom; n < nto; n++) {
const int i1 = anglelist[n].a;
const int i2 = anglelist[n].b;
const int i3 = anglelist[n].c;
const int type = anglelist[n].t;
// 1st bond
const flt_t delx1 = x[i1].x - x[i2].x;
const flt_t dely1 = x[i1].y - x[i2].y;
const flt_t delz1 = x[i1].z - x[i2].z;
const flt_t rsq1 = delx1*delx1 + dely1*dely1 + delz1*delz1;
flt_t ir12 = (flt_t)1.0/sqrt(rsq1);
// 2nd bond
const flt_t delx2 = x[i3].x - x[i2].x;
const flt_t dely2 = x[i3].y - x[i2].y;
const flt_t delz2 = x[i3].z - x[i2].z;
const flt_t rsq2 = delx2*delx2 + dely2*dely2 + delz2*delz2;
ir12 *= (flt_t)1.0/sqrt(rsq2);
// Urey-Bradley bond
const flt_t delxUB = x[i3].x - x[i1].x;
const flt_t delyUB = x[i3].y - x[i1].y;
const flt_t delzUB = x[i3].z - x[i1].z;
const flt_t rsqUB = delxUB*delxUB + delyUB*delyUB + delzUB*delzUB;
const flt_t irUB = (flt_t)1.0/sqrt(rsqUB);
// Urey-Bradley force & energy
const flt_t dr = (flt_t)1.0/irUB - fc.fc[type].r_ub;
const flt_t rk = fc.fc[type].k_ub * dr;
flt_t forceUB;
if (rsqUB > (flt_t)0.0) forceUB = (flt_t)-2.0*rk*irUB;
else forceUB = 0.0;
flt_t eangle;
if (EFLAG) eangle = rk*dr;
// angle (cos and sin)
flt_t c = delx1*delx2 + dely1*dely2 + delz1*delz2;
c *= ir12;
if (c > (flt_t)1.0) c = (flt_t)1.0;
if (c < (flt_t)-1.0) c = (flt_t)-1.0;
const flt_t sd = (flt_t)1.0 - c * c;
flt_t s = (flt_t)1.0 / sqrt(sd);
if (sd < SMALL2) s = INVSMALL;
// harmonic force & energy
const flt_t dtheta = acos(c) - fc.fc[type].theta0;
const flt_t tk = fc.fc[type].k * dtheta;
if (EFLAG) eangle += tk*dtheta;
const flt_t a = (flt_t)-2.0 * tk * s;
const flt_t a11 = a*c / rsq1;
const flt_t a12 = -a * ir12;
const flt_t a22 = a*c / rsq2;
const flt_t f1x = a11*delx1 + a12*delx2 - delxUB*forceUB;
const flt_t f1y = a11*dely1 + a12*dely2 - delyUB*forceUB;
const flt_t f1z = a11*delz1 + a12*delz2 - delzUB*forceUB;
const flt_t f3x = a22*delx2 + a12*delx1 + delxUB*forceUB;
const flt_t f3y = a22*dely2 + a12*dely1 + delyUB*forceUB;
const flt_t f3z = a22*delz2 + a12*delz1 + delzUB*forceUB;
// apply force to each of 3 atoms
if (NEWTON_BOND || i1 < nlocal) {
f[i1].x += f1x;
f[i1].y += f1y;
f[i1].z += f1z;
}
if (NEWTON_BOND || i2 < nlocal) {
f[i2].x -= f1x + f3x;
f[i2].y -= f1y + f3y;
f[i2].z -= f1z + f3z;
}
if (NEWTON_BOND || i3 < nlocal) {
f[i3].x += f3x;
f[i3].y += f3y;
f[i3].z += f3z;
}
if (EVFLAG) {
IP_PRE_ev_tally_angle(EFLAG, eatom, vflag, eangle, i1, i2, i3,f1x,
f1y, f1z, f3x, f3y, f3z, delx1, dely1, delz1,
delx2, dely2, delz2, oeangle, f, NEWTON_BOND,
nlocal, ov0, ov1, ov2, ov3, ov4, ov5);
}
} // for n
} // omp parallel
if (EVFLAG) {
if (EFLAG)
energy += oeangle;
if (vflag) {
virial[0] += ov0; virial[1] += ov1; virial[2] += ov2;
virial[3] += ov3; virial[4] += ov4; virial[5] += ov5;
}
}
fix->set_reduce_flag();
}
/* ---------------------------------------------------------------------- */
void AngleCharmmIntel::init_style()
{
AngleCharmm::init_style();
int ifix = modify->find_fix("package_intel");
if (ifix < 0)
error->all(FLERR,
"The 'package intel' command is required for /intel styles");
fix = static_cast<FixIntel *>(modify->fix[ifix]);
#ifdef _LMP_INTEL_OFFLOAD
_use_base = 0;
if (fix->offload_balance() != 0.0) {
_use_base = 1;
return;
}
#endif
fix->bond_init_check();
if (fix->precision() == FixIntel::PREC_MODE_MIXED)
pack_force_const(force_const_single, fix->get_mixed_buffers());
else if (fix->precision() == FixIntel::PREC_MODE_DOUBLE)
pack_force_const(force_const_double, fix->get_double_buffers());
else
pack_force_const(force_const_single, fix->get_single_buffers());
}
/* ---------------------------------------------------------------------- */
template <class flt_t, class acc_t>
void AngleCharmmIntel::pack_force_const(ForceConst<flt_t> &fc,
IntelBuffers<flt_t,acc_t> *buffers)
{
const int bp1 = atom->nangletypes + 1;
fc.set_ntypes(bp1,memory);
for (int i = 0; i < bp1; i++) {
fc.fc[i].k = k[i];
fc.fc[i].theta0 = theta0[i];
fc.fc[i].k_ub = k_ub[i];
fc.fc[i].r_ub = r_ub[i];
}
}
/* ---------------------------------------------------------------------- */
template <class flt_t>
void AngleCharmmIntel::ForceConst<flt_t>::set_ntypes(const int nangletypes,
Memory *memory) {
if (nangletypes != _nangletypes) {
if (_nangletypes > 0)
_memory->destroy(fc);
if (nangletypes > 0)
_memory->create(fc,nangletypes,"anglecharmmintel.fc");
}
_nangletypes = nangletypes;
_memory = memory;
}
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