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creation + working CPU

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new pair style dpd/charged which is the combination of dpd and coul/slater/long
Working on CPU, GPU in progress
This commit is contained in:
Eddy Barraud
2024-05-31 15:12:37 +02:00
parent 069919ddcd
commit fcdcf65995
8 changed files with 1978 additions and 0 deletions
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187
lib/gpu/lal_dpd_charged.cpp Normal file
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/***************************************************************************
dpd.cpp
-------------------
Trung Dac Nguyen (ORNL)
Class for acceleration of the dpd pair style.
__________________________________________________________________________
This file is part of the LAMMPS Accelerator Library (LAMMPS_AL)
__________________________________________________________________________
begin : Jan 15, 2014
email : nguyentd@ornl.gov
***************************************************************************/
#if defined(USE_OPENCL)
#include "dpd_cl.h"
#elif defined(USE_CUDART)
const char *dpd=0;
#else
#include "dpd_cubin.h"
#endif
#include "lal_dpd.h"
#include <cassert>
namespace LAMMPS_AL {
#define DPDT DPD<numtyp, acctyp>
extern Device<PRECISION,ACC_PRECISION> device;
template <class numtyp, class acctyp>
DPDT::DPD() : BaseDPD<numtyp,acctyp>(), _allocated(false) {
}
template <class numtyp, class acctyp>
DPDT::~DPD() {
clear();
}
template <class numtyp, class acctyp>
int DPDT::bytes_per_atom(const int max_nbors) const {
return this->bytes_per_atom_atomic(max_nbors);
}
template <class numtyp, class acctyp>
int DPDT::init(const int ntypes,
double **host_cutsq, double **host_a0,
double **host_gamma, double **host_sigma,
double **host_cut, double *host_special_lj,
const bool tstat_only,
const int nlocal, const int nall,
const int max_nbors, const int maxspecial,
const double cell_size,
const double gpu_split, FILE *_screen) {
const int max_shared_types=this->device->max_shared_types();
int onetype=0;
#ifdef USE_OPENCL
if (maxspecial==0)
for (int i=1; i<ntypes; i++)
for (int j=i; j<ntypes; j++)
if (host_cutsq[i][j]>0) {
if (onetype>0)
onetype=-1;
else if (onetype==0)
onetype=i*max_shared_types+j;
}
if (onetype<0) onetype=0;
#endif
int success;
success=this->init_atomic(nlocal,nall,max_nbors,maxspecial,cell_size,
gpu_split,_screen,dpd,"k_dpd",onetype);
if (success!=0)
return success;
// If atom type constants fit in shared memory use fast kernel
int lj_types=ntypes;
shared_types=false;
if (lj_types<=max_shared_types && this->_block_size>=max_shared_types) {
lj_types=max_shared_types;
shared_types=true;
}
_lj_types=lj_types;
// Allocate a host write buffer for data initialization
UCL_H_Vec<numtyp> host_write(lj_types*lj_types*32,*(this->ucl_device),
UCL_WRITE_ONLY);
for (int i=0; i<lj_types*lj_types; i++)
host_write[i]=0.0;
coeff.alloc(lj_types*lj_types,*(this->ucl_device),UCL_READ_ONLY);
this->atom->type_pack4(ntypes,lj_types,coeff,host_write,host_a0,host_gamma,
host_sigma,host_cut);
UCL_H_Vec<numtyp> host_rsq(lj_types*lj_types,*(this->ucl_device),
UCL_WRITE_ONLY);
cutsq.alloc(lj_types*lj_types,*(this->ucl_device),UCL_READ_ONLY);
this->atom->type_pack1(ntypes,lj_types,cutsq,host_rsq,host_cutsq);
double special_sqrt[4];
special_sqrt[0] = sqrt(host_special_lj[0]);
special_sqrt[1] = sqrt(host_special_lj[1]);
special_sqrt[2] = sqrt(host_special_lj[2]);
special_sqrt[3] = sqrt(host_special_lj[3]);
UCL_H_Vec<double> dview;
sp_lj.alloc(4,*(this->ucl_device),UCL_READ_ONLY);
dview.view(host_special_lj,4,*(this->ucl_device));
ucl_copy(sp_lj,dview,false);
sp_sqrt.alloc(4,*(this->ucl_device),UCL_READ_ONLY);
dview.view(special_sqrt,4,*(this->ucl_device));
ucl_copy(sp_sqrt,dview,false);
_tstat_only = 0;
if (tstat_only) _tstat_only=1;
_allocated=true;
this->_max_bytes=coeff.row_bytes()+cutsq.row_bytes()+sp_lj.row_bytes()+sp_sqrt.row_bytes();
return 0;
}
template <class numtyp, class acctyp>
void DPDT::clear() {
if (!_allocated)
return;
_allocated=false;
coeff.clear();
cutsq.clear();
sp_lj.clear();
sp_sqrt.clear();
this->clear_atomic();
}
template <class numtyp, class acctyp>
double DPDT::host_memory_usage() const {
return this->host_memory_usage_atomic()+sizeof(DPD<numtyp,acctyp>);
}
// ---------------------------------------------------------------------------
// Calculate energies, forces, and torques
// ---------------------------------------------------------------------------
template <class numtyp, class acctyp>
int DPDT::loop(const int eflag, const int vflag) {
// Compute the block size and grid size to keep all cores busy
const int BX=this->block_size();
int GX=static_cast<int>(ceil(static_cast<double>(this->ans->inum())/
(BX/this->_threads_per_atom)));
int ainum=this->ans->inum();
int nbor_pitch=this->nbor->nbor_pitch();
this->time_pair.start();
if (shared_types) {
this->k_pair_sel->set_size(GX,BX);
this->k_pair_sel->run(&this->atom->x, &coeff, &sp_lj, &sp_sqrt,
&this->nbor->dev_nbor, &this->_nbor_data->begin(),
&this->ans->force, &this->ans->engv, &eflag,
&vflag, &ainum, &nbor_pitch, &this->atom->v, &cutsq,
&this->_dtinvsqrt, &this->_seed, &this->_timestep,
&this->_tstat_only, &this->_threads_per_atom);
} else {
this->k_pair.set_size(GX,BX);
this->k_pair.run(&this->atom->x, &coeff, &_lj_types, &sp_lj, &sp_sqrt,
&this->nbor->dev_nbor, &this->_nbor_data->begin(),
&this->ans->force, &this->ans->engv, &eflag, &vflag,
&ainum, &nbor_pitch, &this->atom->v, &cutsq, &this->_dtinvsqrt,
&this->_seed, &this->_timestep, &this->_tstat_only,
&this->_threads_per_atom);
}
this->time_pair.stop();
return GX;
}
template <class numtyp, class acctyp>
void DPDT::update_coeff(int ntypes, double **host_a0, double **host_gamma,
double **host_sigma, double **host_cut)
{
UCL_H_Vec<numtyp> host_write(_lj_types*_lj_types*32,*(this->ucl_device),
UCL_WRITE_ONLY);
this->atom->type_pack4(ntypes,_lj_types,coeff,host_write,host_a0,host_gamma,
host_sigma,host_cut);
}
template class DPD<PRECISION,ACC_PRECISION>;
}

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lib/gpu/lal_dpd_charged.cu Normal file
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// **************************************************************************
// dpd.cu
// -------------------
// Trung Dac Nguyen (ORNL)
//
// Device code for acceleration of the dpd pair style
//
// __________________________________________________________________________
// This file is part of the LAMMPS Accelerator Library (LAMMPS_AL)
// __________________________________________________________________________
//
// begin : Jan 15, 2014
// email : nguyentd@ornl.gov
// ***************************************************************************
#if defined(NV_KERNEL) || defined(USE_HIP)
#include "lal_aux_fun1.h"
#ifndef _DOUBLE_DOUBLE
_texture( pos_tex,float4);
_texture( vel_tex,float4);
#else
_texture_2d( pos_tex,int4);
_texture_2d( vel_tex,int4);
#endif
#else
#define pos_tex x_
#define vel_tex v_
#endif
#define EPSILON (numtyp)1.0e-10
//#define _USE_UNIFORM_SARU_LCG
//#define _USE_UNIFORM_SARU_TEA8
//#define _USE_GAUSSIAN_SARU_LCG
#if !defined(_USE_UNIFORM_SARU_LCG) && !defined(_USE_UNIFORM_SARU_TEA8) && !defined(_USE_GAUSSIAN_SARU_LCG)
#define _USE_UNIFORM_SARU_LCG
#endif
// References:
// 1. Y. Afshar, F. Schmid, A. Pishevar, S. Worley, Comput. Phys. Comm. 184 (2013), 1119–1128.
// 2. C. L. Phillips, J. A. Anderson, S. C. Glotzer, Comput. Phys. Comm. 230 (2011), 7191-7201.
// PRNG period = 3666320093*2^32 ~ 2^64 ~ 10^19
#define LCGA 0x4beb5d59 /* Full period 32 bit LCG */
#define LCGC 0x2600e1f7
#define oWeylPeriod 0xda879add /* Prime period 3666320093 */
#define oWeylOffset 0x8009d14b
#define TWO_N32 0.232830643653869628906250e-9f /* 2^-32 */
// specifically implemented for steps = 1; high = 1.0; low = -1.0
// returns uniformly distributed random numbers u in [-1.0;1.0]
// using the inherent LCG, then multiply u with sqrt(3) to "match"
// with a normal random distribution.
// Afshar et al. mutlplies u in [-0.5;0.5] with sqrt(12)
// Curly brackets to make variables local to the scope.
#ifdef _USE_UNIFORM_SARU_LCG
#define SQRT3 (numtyp)1.7320508075688772935274463
#define saru(seed1, seed2, seed, timestep, randnum) { \
unsigned int seed3 = seed + timestep; \
seed3^=(seed1<<7)^(seed2>>6); \
seed2+=(seed1>>4)^(seed3>>15); \
seed1^=(seed2<<9)+(seed3<<8); \
seed3^=0xA5366B4D*((seed2>>11) ^ (seed1<<1)); \
seed2+=0x72BE1579*((seed1<<4) ^ (seed3>>16)); \
seed1^=0x3F38A6ED*((seed3>>5) ^ (((signed int)seed2)>>22)); \
seed2+=seed1*seed3; \
seed1+=seed3 ^ (seed2>>2); \
seed2^=((signed int)seed2)>>17; \
unsigned int state = 0x79dedea3*(seed1^(((signed int)seed1)>>14)); \
unsigned int wstate = (state + seed2) ^ (((signed int)state)>>8); \
state = state + (wstate*(wstate^0xdddf97f5)); \
wstate = 0xABCB96F7 + (wstate>>1); \
state = LCGA*state + LCGC; \
wstate = wstate + oWeylOffset+((((signed int)wstate)>>31) & oWeylPeriod); \
unsigned int v = (state ^ (state>>26)) + wstate; \
unsigned int s = (signed int)((v^(v>>20))*0x6957f5a7); \
randnum = SQRT3*(s*TWO_N32*(numtyp)2.0-(numtyp)1.0); \
}
#endif
// specifically implemented for steps = 1; high = 1.0; low = -1.0
// returns uniformly distributed random numbers u in [-1.0;1.0] using TEA8
// then multiply u with sqrt(3) to "match" with a normal random distribution
// Afshar et al. mutlplies u in [-0.5;0.5] with sqrt(12)
#ifdef _USE_UNIFORM_SARU_TEA8
#define SQRT3 (numtyp)1.7320508075688772935274463
#define k0 0xA341316C
#define k1 0xC8013EA4
#define k2 0xAD90777D
#define k3 0x7E95761E
#define delta 0x9e3779b9
#define rounds 8
#define saru(seed1, seed2, seed, timestep, randnum) { \
unsigned int seed3 = seed + timestep; \
seed3^=(seed1<<7)^(seed2>>6); \
seed2+=(seed1>>4)^(seed3>>15); \
seed1^=(seed2<<9)+(seed3<<8); \
seed3^=0xA5366B4D*((seed2>>11) ^ (seed1<<1)); \
seed2+=0x72BE1579*((seed1<<4) ^ (seed3>>16)); \
seed1^=0x3F38A6ED*((seed3>>5) ^ (((signed int)seed2)>>22)); \
seed2+=seed1*seed3; \
seed1+=seed3 ^ (seed2>>2); \
seed2^=((signed int)seed2)>>17; \
unsigned int state = 0x79dedea3*(seed1^(((signed int)seed1)>>14)); \
unsigned int wstate = (state + seed2) ^ (((signed int)state)>>8); \
state = state + (wstate*(wstate^0xdddf97f5)); \
wstate = 0xABCB96F7 + (wstate>>1); \
unsigned int sum = 0; \
for (int i=0; i < rounds; i++) { \
sum += delta; \
state += ((wstate<<4) + k0)^(wstate + sum)^((wstate>>5) + k1); \
wstate += ((state<<4) + k2)^(state + sum)^((state>>5) + k3); \
} \
unsigned int v = (state ^ (state>>26)) + wstate; \
unsigned int s = (signed int)((v^(v>>20))*0x6957f5a7); \
randnum = SQRT3*(s*TWO_N32*(numtyp)2.0-(numtyp)1.0); \
}
#endif
// specifically implemented for steps = 1; high = 1.0; low = -1.0
// returns two uniformly distributed random numbers r1 and r2 in [-1.0;1.0],
// and uses the polar method (Marsaglia's) to transform to a normal random value
// This is used to compared with CPU DPD using RandMars::gaussian()
#ifdef _USE_GAUSSIAN_SARU_LCG
#define saru(seed1, seed2, seed, timestep, randnum) { \
unsigned int seed3 = seed + timestep; \
seed3^=(seed1<<7)^(seed2>>6); \
seed2+=(seed1>>4)^(seed3>>15); \
seed1^=(seed2<<9)+(seed3<<8); \
seed3^=0xA5366B4D*((seed2>>11) ^ (seed1<<1)); \
seed2+=0x72BE1579*((seed1<<4) ^ (seed3>>16)); \
seed1^=0x3F38A6ED*((seed3>>5) ^ (((signed int)seed2)>>22)); \
seed2+=seed1*seed3; \
seed1+=seed3 ^ (seed2>>2); \
seed2^=((signed int)seed2)>>17; \
unsigned int state=0x12345678; \
unsigned int wstate=12345678; \
state = 0x79dedea3*(seed1^(((signed int)seed1)>>14)); \
wstate = (state + seed2) ^ (((signed int)state)>>8); \
state = state + (wstate*(wstate^0xdddf97f5)); \
wstate = 0xABCB96F7 + (wstate>>1); \
unsigned int v, s; \
numtyp r1, r2, rsq; \
while (1) { \
state = LCGA*state + LCGC; \
wstate = wstate + oWeylOffset+((((signed int)wstate)>>31) & oWeylPeriod); \
v = (state ^ (state>>26)) + wstate; \
s = (signed int)((v^(v>>20))*0x6957f5a7); \
r1 = s*TWO_N32*(numtyp)2.0-(numtyp)1.0; \
state = LCGA*state + LCGC; \
wstate = wstate + oWeylOffset+((((signed int)wstate)>>31) & oWeylPeriod); \
v = (state ^ (state>>26)) + wstate; \
s = (signed int)((v^(v>>20))*0x6957f5a7); \
r2 = s*TWO_N32*(numtyp)2.0-(numtyp)1.0; \
rsq = r1 * r1 + r2 * r2; \
if (rsq < (numtyp)1.0) break; \
} \
numtyp fac = ucl_sqrt((numtyp)-2.0*log(rsq)/rsq); \
randnum = r2*fac; \
}
#endif
__kernel void k_dpd(const __global numtyp4 *restrict x_,
const __global numtyp4 *restrict coeff,
const int lj_types,
const __global numtyp *restrict sp_lj,
const __global numtyp *restrict sp_sqrt,
const __global int * dev_nbor,
const __global int * dev_packed,
__global acctyp3 *restrict ans,
__global acctyp *restrict engv,
const int eflag, const int vflag, const int inum,
const int nbor_pitch,
const __global numtyp4 *restrict v_,
const __global numtyp *restrict cutsq,
const numtyp dtinvsqrt, const int seed,
const int timestep, const int tstat_only,
const int t_per_atom) {
int tid, ii, offset;
atom_info(t_per_atom,ii,tid,offset);
int n_stride;
local_allocate_store_pair();
acctyp3 f;
f.x=(acctyp)0; f.y=(acctyp)0; f.z=(acctyp)0;
acctyp energy, virial[6];
if (EVFLAG) {
energy=(acctyp)0;
for (int i=0; i<6; i++) virial[i]=(acctyp)0;
}
if (ii<inum) {
int i, numj, nbor, nbor_end;
nbor_info(dev_nbor,dev_packed,nbor_pitch,t_per_atom,ii,offset,i,numj,
n_stride,nbor_end,nbor);
numtyp4 ix; fetch4(ix,i,pos_tex); //x_[i];
int itype=ix.w;
numtyp4 iv; fetch4(iv,i,vel_tex); //v_[i];
int itag=iv.w;
numtyp factor_dpd, factor_sqrt;
for ( ; nbor<nbor_end; nbor+=n_stride) {
ucl_prefetch(dev_packed+nbor+n_stride);
int j=dev_packed[nbor];
factor_dpd = sp_lj[sbmask(j)];
factor_sqrt = sp_sqrt[sbmask(j)];
j &= NEIGHMASK;
numtyp4 jx; fetch4(jx,j,pos_tex); //x_[j];
int jtype=jx.w;
numtyp4 jv; fetch4(jv,j,vel_tex); //v_[j];
int jtag=jv.w;
// Compute r12
numtyp delx = ix.x-jx.x;
numtyp dely = ix.y-jx.y;
numtyp delz = ix.z-jx.z;
numtyp rsq = delx*delx+dely*dely+delz*delz;
int mtype=itype*lj_types+jtype;
if (rsq<cutsq[mtype]) {
numtyp r=ucl_sqrt(rsq);
if (r < EPSILON) continue;
numtyp rinv=ucl_recip(r);
numtyp delvx = iv.x - jv.x;
numtyp delvy = iv.y - jv.y;
numtyp delvz = iv.z - jv.z;
numtyp dot = delx*delvx + dely*delvy + delz*delvz;
numtyp wd = (numtyp)1.0 - r/coeff[mtype].w;
unsigned int tag1=itag, tag2=jtag;
if (tag1 > tag2) {
tag1 = jtag; tag2 = itag;
}
numtyp randnum = (numtyp)0.0;
saru(tag1, tag2, seed, timestep, randnum);
// conservative force = a0 * wd, or 0 if tstat only
// drag force = -gamma * wd^2 * (delx dot delv) / r
// random force = sigma * wd * rnd * dtinvsqrt;
numtyp force = (numtyp)0.0;
if (!tstat_only) force = coeff[mtype].x*wd;
force -= coeff[mtype].y*wd*wd*dot*rinv;
force *= factor_dpd;
force += factor_sqrt*coeff[mtype].z*wd*randnum*dtinvsqrt;
force*=rinv;
f.x+=delx*force;
f.y+=dely*force;
f.z+=delz*force;
if (EVFLAG && eflag) {
// unshifted eng of conservative term:
// evdwl = -a0[itype][jtype]*r * (1.0-0.5*r/cut[itype][jtype]);
// eng shifted to 0.0 at cutoff
numtyp e = (numtyp)0.5*coeff[mtype].x*coeff[mtype].w * wd*wd;
energy+=factor_dpd*e;
}
if (EVFLAG && vflag) {
virial[0] += delx*delx*force;
virial[1] += dely*dely*force;
virial[2] += delz*delz*force;
virial[3] += delx*dely*force;
virial[4] += delx*delz*force;
virial[5] += dely*delz*force;
}
}
} // for nbor
} // if ii
store_answers(f,energy,virial,ii,inum,tid,t_per_atom,offset,eflag,vflag,
ans,engv);
}
__kernel void k_dpd_fast(const __global numtyp4 *restrict x_,
const __global numtyp4 *restrict coeff_in,
const __global numtyp *restrict sp_lj_in,
const __global numtyp *restrict sp_sqrt_in,
const __global int * dev_nbor,
const __global int * dev_packed,
__global acctyp3 *restrict ans,
__global acctyp *restrict engv,
const int eflag, const int vflag, const int inum,
const int nbor_pitch,
const __global numtyp4 *restrict v_,
const __global numtyp *restrict cutsq,
const numtyp dtinvsqrt, const int seed,
const int timestep, const int tstat_only,
const int t_per_atom) {
int tid, ii, offset;
atom_info(t_per_atom,ii,tid,offset);
#ifndef ONETYPE
__local numtyp4 coeff[MAX_SHARED_TYPES*MAX_SHARED_TYPES];
__local numtyp sp_lj[4];
__local numtyp sp_sqrt[4];
if (tid<4) {
sp_lj[tid]=sp_lj_in[tid];
sp_sqrt[tid]=sp_sqrt_in[tid];
}
if (tid<MAX_SHARED_TYPES*MAX_SHARED_TYPES) {
coeff[tid]=coeff_in[tid];
}
__syncthreads();
#else
const numtyp coeffx=coeff_in[ONETYPE].x;
const numtyp coeffy=coeff_in[ONETYPE].y;
const numtyp coeffz=coeff_in[ONETYPE].z;
const numtyp coeffw=coeff_in[ONETYPE].w;
const numtyp cutsq_p=cutsq[ONETYPE];
#endif
int n_stride;
local_allocate_store_pair();
acctyp3 f;
f.x=(acctyp)0; f.y=(acctyp)0; f.z=(acctyp)0;
acctyp energy, virial[6];
if (EVFLAG) {
energy=(acctyp)0;
for (int i=0; i<6; i++) virial[i]=(acctyp)0;
}
if (ii<inum) {
int i, numj, nbor, nbor_end;
nbor_info(dev_nbor,dev_packed,nbor_pitch,t_per_atom,ii,offset,i,numj,
n_stride,nbor_end,nbor);
numtyp4 ix; fetch4(ix,i,pos_tex); //x_[i];
#ifndef ONETYPE
int iw=ix.w;
int itype=fast_mul((int)MAX_SHARED_TYPES,iw);
#endif
numtyp4 iv; fetch4(iv,i,vel_tex); //v_[i];
int itag=iv.w;
#ifndef ONETYPE
numtyp factor_dpd, factor_sqrt;
#endif
for ( ; nbor<nbor_end; nbor+=n_stride) {
ucl_prefetch(dev_packed+nbor+n_stride);
int j=dev_packed[nbor];
#ifndef ONETYPE
factor_dpd = sp_lj[sbmask(j)];
factor_sqrt = sp_sqrt[sbmask(j)];
j &= NEIGHMASK;
#endif
numtyp4 jx; fetch4(jx,j,pos_tex); //x_[j];
#ifndef ONETYPE
int mtype=itype+jx.w;
const numtyp cutsq_p=cutsq[mtype];
#endif
numtyp4 jv; fetch4(jv,j,vel_tex); //v_[j];
int jtag=jv.w;
// Compute r12
numtyp delx = ix.x-jx.x;
numtyp dely = ix.y-jx.y;
numtyp delz = ix.z-jx.z;
numtyp rsq = delx*delx+dely*dely+delz*delz;
if (rsq<cutsq_p) {
numtyp r=ucl_sqrt(rsq);
if (r < EPSILON) continue;
numtyp rinv=ucl_recip(r);
numtyp delvx = iv.x - jv.x;
numtyp delvy = iv.y - jv.y;
numtyp delvz = iv.z - jv.z;
numtyp dot = delx*delvx + dely*delvy + delz*delvz;
#ifndef ONETYPE
const numtyp coeffw=coeff[mtype].w;
#endif
numtyp wd = (numtyp)1.0 - r/coeffw;
unsigned int tag1=itag, tag2=jtag;
if (tag1 > tag2) {
tag1 = jtag; tag2 = itag;
}
numtyp randnum = (numtyp)0.0;
saru(tag1, tag2, seed, timestep, randnum);
// conservative force = a0 * wd, or 0 if tstat only
// drag force = -gamma * wd^2 * (delx dot delv) / r
// random force = sigma * wd * rnd * dtinvsqrt;
#ifndef ONETYPE
const numtyp coeffx=coeff[mtype].x;
const numtyp coeffy=coeff[mtype].y;
const numtyp coeffz=coeff[mtype].z;
#endif
numtyp force = (numtyp)0.0;
if (!tstat_only) force = coeffx*wd;
force -= coeffy*wd*wd*dot*rinv;
#ifndef ONETYPE
force *= factor_dpd;
force += factor_sqrt*coeffz*wd*randnum*dtinvsqrt;
#else
force += coeffz*wd*randnum*dtinvsqrt;
#endif
force*=rinv;
f.x+=delx*force;
f.y+=dely*force;
f.z+=delz*force;
if (EVFLAG && eflag) {
// unshifted eng of conservative term:
// evdwl = -a0[itype][jtype]*r * (1.0-0.5*r/cut[itype][jtype]);
// eng shifted to 0.0 at cutoff
numtyp e = (numtyp)0.5*coeffx*coeffw * wd*wd;
#ifndef ONETYPE
energy+=factor_dpd*e;
#else
energy+=e;
#endif
}
if (EVFLAG && vflag) {
virial[0] += delx*delx*force;
virial[1] += dely*dely*force;
virial[2] += delz*delz*force;
virial[3] += delx*dely*force;
virial[4] += delx*delz*force;
virial[5] += dely*delz*force;
}
}
} // for nbor
} // if ii
store_answers(f,energy,virial,ii,inum,tid,t_per_atom,offset,eflag,vflag,
ans,engv);
}

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/***************************************************************************
dpd.h
-------------------
Trung Dac Nguyen (ORNL)
Class for acceleration of the dpd pair style.
__________________________________________________________________________
This file is part of the LAMMPS Accelerator Library (LAMMPS_AL)
__________________________________________________________________________
begin : Jan 15, 2014
email : nguyentd@ornl.gov
***************************************************************************/
#ifndef LAL_DPD_CHARGED_H
#define LAL_DPD_CHARGED_H
#include "lal_base_dpd.h"
namespace LAMMPS_AL {
template <class numtyp, class acctyp>
class DPDCharged : public BaseDPD<numtyp, acctyp> {
public:
DPDCharged();
~DPDCharged();
/// Clear any previous data and set up for a new LAMMPS run
/** \param max_nbors initial number of rows in the neighbor matrix
* \param cell_size cutoff + skin
* \param gpu_split fraction of particles handled by device
*
* Returns:
* - 0 if successful
* - -1 if fix gpu not found
* - -3 if there is an out of memory error
* - -4 if the GPU library was not compiled for GPU
* - -5 Double precision is not supported on card **/
int init(const int ntypes, double **host_cutsq, double **host_a0,
double **host_gamma, double **host_sigma, double **host_cut,
double *host_special_lj, bool tstat_only, const int nlocal,
const int nall, const int max_nbors, const int maxspecial,
const double cell_size, const double gpu_split, FILE *screen);
/// Clear all host and device data
/** \note This is called at the beginning of the init() routine **/
void clear();
/// Returns memory usage on device per atom
int bytes_per_atom(const int max_nbors) const;
/// Total host memory used by library for pair style
double host_memory_usage() const;
/// Update coeff if needed (tstat only)
void update_coeff(int ntypes, double **host_a0, double **host_gamma,
double **host_sigma, double **host_cut);
// --------------------------- TYPE DATA --------------------------
/// coeff.x = a0, coeff.y = gamma, coeff.z = sigma, coeff.w = cut
UCL_D_Vec<numtyp4> coeff;
UCL_D_Vec<numtyp> cutsq;
/// Special LJ values
UCL_D_Vec<numtyp> sp_lj, sp_sqrt;
/// If atom type constants fit in shared memory, use fast kernels
bool shared_types;
/// Number of atom types
int _lj_types;
/// Only used for thermostat
int _tstat_only;
/// pointer to host data of charge
double *
private:
bool _allocated;
int loop(const int eflag, const int vflag);
};
}
#endif

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/***************************************************************************
dpd_ext.cpp
-------------------
Trung Dac Nguyen (ORNL)
Functions for LAMMPS access to dpd acceleration routines.
__________________________________________________________________________
This file is part of the LAMMPS Accelerator Library (LAMMPS_AL)
__________________________________________________________________________
begin : Jan 15, 2014
email : nguyentd@ornl.gov
***************************************************************************/
#include <iostream>
#include <cassert>
#include <cmath>
#include "lal_dpd.h"
using namespace std;
using namespace LAMMPS_AL;
static DPD<PRECISION,ACC_PRECISION> DPDCMF;
// ---------------------------------------------------------------------------
// Allocate memory on host and device and copy constants to device
// ---------------------------------------------------------------------------
int dpd_charged_gpu_init(const int ntypes, double **cutsq, double **host_a0,
double **host_gamma, double **host_sigma, double **host_cut,
double *special_lj, const int inum,
const int nall, const int max_nbors, const int maxspecial,
const double cell_size, int &gpu_mode, FILE *screen) {
DPDCMF.clear();
gpu_mode=DPDCMF.device->gpu_mode();
double gpu_split=DPDCMF.device->particle_split();
int first_gpu=DPDCMF.device->first_device();
int last_gpu=DPDCMF.device->last_device();
int world_me=DPDCMF.device->world_me();
int gpu_rank=DPDCMF.device->gpu_rank();
int procs_per_gpu=DPDCMF.device->procs_per_gpu();
DPDCMF.device->init_message(screen,"dpd",first_gpu,last_gpu);
bool message=false;
if (DPDCMF.device->replica_me()==0 && screen)
message=true;
if (message) {
fprintf(screen,"Initializing Device and compiling on process 0...");
fflush(screen);
}
int init_ok=0;
if (world_me==0)
init_ok=DPDCMF.init(ntypes, cutsq, host_a0, host_gamma, host_sigma,
host_cut, special_lj, false, inum, nall, max_nbors,
maxspecial, cell_size, gpu_split, screen);
DPDCMF.device->world_barrier();
if (message)
fprintf(screen,"Done.\n");
for (int i=0; i<procs_per_gpu; i++) {
if (message) {
if (last_gpu-first_gpu==0)
fprintf(screen,"Initializing Device %d on core %d...",first_gpu,i);
else
fprintf(screen,"Initializing Devices %d-%d on core %d...",first_gpu,
last_gpu,i);
fflush(screen);
}
if (gpu_rank==i && world_me!=0)
init_ok=DPDCMF.init(ntypes, cutsq, host_a0, host_gamma, host_sigma,
host_cut, special_lj, false, inum, nall, max_nbors,
maxspecial, cell_size, gpu_split, screen);
DPDCMF.device->serialize_init();
if (message)
fprintf(screen,"Done.\n");
}
if (message)
fprintf(screen,"\n");
if (init_ok==0)
DPDCMF.estimate_gpu_overhead();
return init_ok;
}
void dpd_charged_gpu_clear() {
DPDCMF.clear();
}
int ** dpd_charged_gpu_compute_n(const int ago, const int inum_full, const int nall,
double **host_x, int *host_type, double *sublo,
double *subhi, tagint *tag, int **nspecial,
tagint **special, const bool eflag, const bool vflag,
const bool eatom, const bool vatom, int &host_start,
int **ilist, int **jnum, const double cpu_time, bool &success,
double **host_v, const double dtinvsqrt,
const int seed, const int timestep,
double *boxlo, double *prd) {
return DPDCMF.compute(ago, inum_full, nall, host_x, host_type, sublo,
subhi, tag, nspecial, special, eflag, vflag, eatom,
vatom, host_start, ilist, jnum, cpu_time, success,
host_v, dtinvsqrt, seed, timestep, boxlo, prd);
}
void dpd_charged_gpu_compute(const int ago, const int inum_full, const int nall,
double **host_x, int *host_type, int *ilist, int *numj,
int **firstneigh, const bool eflag, const bool vflag,
const bool eatom, const bool vatom, int &host_start,
const double cpu_time, bool &success, tagint *tag,
double **host_v, const double dtinvsqrt,
const int seed, const int timestep,
const int nlocal, double *boxlo, double *prd) {
DPDCMF.compute(ago, inum_full, nall, host_x, host_type, ilist, numj,
firstneigh, eflag, vflag, eatom, vatom, host_start, cpu_time, success,
tag, host_v, dtinvsqrt, seed, timestep, nlocal, boxlo, prd);
}
void dpd_charged_gpu_update_coeff(int ntypes, double **host_a0, double **host_gamma,
double **host_sigma, double **host_cut)
{
DPDCMF.update_coeff(ntypes,host_a0,host_gamma,host_sigma,host_cut);
}
double dpd_charged_gpu_bytes() {
return DPDCMF.host_memory_usage();
}

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// clang-format off
/* ----------------------------------------------------------------------
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: Kurt Smith (U Pittsburgh)
------------------------------------------------------------------------- */
#include "pair_dpd_charged.h"
#include "atom.h"
#include "comm.h"
#include "error.h"
#include "force.h"
#include "memory.h"
#include "neigh_list.h"
#include "neighbor.h"
#include "random_mars.h"
#include "update.h"
#include "ewald_const.h"
#include "kspace.h"
#include <cmath>
#include <cstring>
using namespace LAMMPS_NS;
using namespace EwaldConst;
static constexpr double EPSILON = 1.0e-10;
/* ---------------------------------------------------------------------- */
PairDPDCharged::PairDPDCharged(LAMMPS *lmp) : Pair(lmp)
{
writedata = 1;
ewaldflag = pppmflag = 1;
qdist = 0.0;
random = nullptr;
}
/* ---------------------------------------------------------------------- */
PairDPDCharged::~PairDPDCharged()
{
if (copymode) return;
if (allocated) {
memory->destroy(setflag);
memory->destroy(cutsq);
memory->destroy(cut_dpd);
memory->destroy(cut_dpdsq);
memory->destroy(cut_slater);
memory->destroy(cut_slatersq);
memory->destroy(cut);
memory->destroy(a0);
memory->destroy(gamma);
memory->destroy(sigma);
memory->destroy(scale);
}
if (random) delete random;
}
/* ---------------------------------------------------------------------- */
void PairDPDCharged::compute(int eflag, int vflag)
{
int i,j,ii,jj,inum,jnum,itype,jtype;
double qtmp,xtmp,ytmp,ztmp,delx,dely,delz,evdwl,ecoul,fpair;
double vxtmp,vytmp,vztmp,delvx,delvy,delvz;
double r2inv,forcedpd,forcecoul,factor_coul;
double grij,expm2,prefactor,t,erfc;
double rsq,r,rinv,dot,wd,randnum,factor_dpd,factor_sqrt;
int *ilist,*jlist,*numneigh,**firstneigh;
double slater_term;
evdwl = 0.0;
ev_init(eflag,vflag);
ecoul = 0.0;
double **x = atom->x;
double **v = atom->v;
double **f = atom->f;
int *type = atom->type;
int nlocal = atom->nlocal;
double *special_lj = force->special_lj;
int newton_pair = force->newton_pair;
double dtinvsqrt = 1.0/sqrt(update->dt);
double *q = atom->q;
double *special_coul = force->special_coul;
double qqrd2e = force->qqrd2e;
inum = list->inum;
ilist = list->ilist;
numneigh = list->numneigh;
firstneigh = list->firstneigh;
// loop over neighbors of my atoms
for (ii = 0; ii < inum; ii++) {
i = ilist[ii];
qtmp = q[i];
xtmp = x[i][0];
ytmp = x[i][1];
ztmp = x[i][2];
vxtmp = v[i][0];
vytmp = v[i][1];
vztmp = v[i][2];
itype = type[i];
jlist = firstneigh[i];
jnum = numneigh[i];
for (jj = 0; jj < jnum; jj++) {
j = jlist[jj];
factor_dpd = special_lj[sbmask(j)];
factor_sqrt = special_sqrt[sbmask(j)];
factor_coul = special_coul[sbmask(j)];
j &= NEIGHMASK;
delx = xtmp - x[j][0];
dely = ytmp - x[j][1];
delz = ztmp - x[j][2];
rsq = delx*delx + dely*dely + delz*delz;
jtype = type[j];
// forces if below maximum cutoff
if (rsq < cutsq[itype][jtype]) {
r = sqrt(rsq);
if (r < EPSILON) continue; // r can be 0.0 in DPD systems
// apply DPD force if distance below DPD cutoff
if (rsq < cut_dpdsq[itype][jtype]) {
rinv = 1.0/r;
delvx = vxtmp - v[j][0];
delvy = vytmp - v[j][1];
delvz = vztmp - v[j][2];
dot = delx*delvx + dely*delvy + delz*delvz;
wd = 1.0 - r/cut_dpd[itype][jtype];
randnum = random->gaussian();
// conservative force = a0 * wd
// drag force = -gamma * wd^2 * (delx dot delv) / r
// random force = sigma * wd * rnd * dtinvsqrt;
// random force must be scaled by sqrt(factor_dpd)
forcedpd = a0[itype][jtype]*wd;
forcedpd -= gamma[itype][jtype]*wd*wd*dot*rinv;
forcedpd *= factor_dpd;
forcedpd += factor_sqrt*sigma[itype][jtype]*wd*randnum*dtinvsqrt;
forcedpd *= rinv;
} else forcedpd = 0.0;
// apply Slater electrostatic force if distance below Slater cutoff
// and the two species are charged
if (cut_slater[itype][jtype] != 0.0 && rsq < cut_slatersq[itype][jtype]){
r2inv = 1.0/rsq;
grij = g_ewald * r;
expm2 = exp(-grij*grij);
t = 1.0 / (1.0 + EWALD_P*grij);
erfc = t * (A1+t*(A2+t*(A3+t*(A4+t*A5)))) * expm2;
slater_term = exp(-2*r/lamda)*(1 + (2*r/lamda*(1+r/lamda)));
prefactor = qqrd2e * scale[itype][jtype] * qtmp*q[j]/r;
forcecoul = prefactor * (erfc + EWALD_F*grij*expm2 - slater_term);
if (factor_coul < 1.0) forcecoul -= (1.0-factor_coul)*prefactor*(1-slater_term);
forcecoul *= r2inv;
} else forcecoul = 0.0;
fpair = forcedpd + forcecoul;
f[i][0] += delx*fpair;
f[i][1] += dely*fpair;
f[i][2] += delz*fpair;
if (newton_pair || j < nlocal) {
f[j][0] -= delx*fpair;
f[j][1] -= dely*fpair;
f[j][2] -= delz*fpair;
}
// tallies global or per-atom energy and virial only if needed
if (eflag) {
if (rsq < cut_dpdsq[itype][jtype]) {
// eng shifted to 0.0 at cutoff
evdwl = 0.5*a0[itype][jtype]*cut_dpd[itype][jtype] * wd*wd;
evdwl *= factor_dpd;
} else evdwl = 0.0;
if (cut_slater[itype][jtype] != 0.0 && rsq < cut_slatersq[itype][jtype]){
ecoul = prefactor*(erfc - (1 + r/lamda)*exp(-2*r/lamda));
if (factor_coul < 1.0) ecoul -= (1.0-factor_coul)*prefactor*(1.0-(1 + r/lamda)*exp(-2*r/lamda));
} else ecoul = 0.0;
}
if (evflag) ev_tally(i,j,nlocal,newton_pair,
evdwl,ecoul,fpair,delx,dely,delz);
}
}
}
if (vflag_fdotr) virial_fdotr_compute();
}
/* ----------------------------------------------------------------------
allocate all arrays
------------------------------------------------------------------------- */
void PairDPDCharged::allocate()
{
int i,j;
allocated = 1;
int n = atom->ntypes;
memory->create(setflag,n+1,n+1,"pair:setflag");
for (i = 1; i <= n; i++)
for (j = i; j <= n; j++)
setflag[i][j] = 0;
memory->create(cutsq,n+1,n+1,"pair:cutsq");
memory->create(scale,n+1,n+1,"pair:scale");
memory->create(cut,n+1,n+1,"pair:cut");
memory->create(cut_dpd,n+1,n+1,"pair:cut_dpd");
memory->create(cut_dpdsq,n+1,n+1,"pair:cut_dpdsq");
memory->create(cut_slater,n+1,n+1,"pair:cut_slater");
memory->create(cut_slatersq,n+1,n+1,"pair:cut_slatersq");
memory->create(a0,n+1,n+1,"pair:a0");
memory->create(gamma,n+1,n+1,"pair:gamma");
memory->create(sigma,n+1,n+1,"pair:sigma");
for (i = 0; i <= atom->ntypes; i++)
for (j = 0; j <= atom->ntypes; j++)
sigma[i][j] = gamma[i][j] = 0.0;
}
/* ----------------------------------------------------------------------
global settings
------------------------------------------------------------------------- */
void PairDPDCharged::settings(int narg, char **arg)
{
// params : T cut_dpd seed lambda cut_coul
if (narg != 5) error->all(FLERR,"Illegal pair_style command");
temperature = utils::numeric(FLERR,arg[0],false,lmp);
cut_global = utils::numeric(FLERR,arg[1],false,lmp);
seed = utils::inumeric(FLERR,arg[2],false,lmp);
lamda = utils::numeric(FLERR,arg[3],false,lmp);
cut_coul = utils::numeric(FLERR,arg[4],false,lmp);
// initialize Marsaglia RNG with processor-unique seed
if (seed <= 0) error->all(FLERR,"Illegal pair_style command");
delete random;
random = new RanMars(lmp,seed + comm->me);
// reset cutoffs that have been explicitly set
if (allocated) {
int i,j;
for (i = 1; i <= atom->ntypes; i++)
for (j = i; j <= atom->ntypes; j++)
if (setflag[i][j]) cut_dpd[i][j] = MAX(cut_global,cut_coul);
}
}
/* ----------------------------------------------------------------------
set coeffs for one or more type pairs
------------------------------------------------------------------------- */
void PairDPDCharged::coeff(int narg, char **arg)
{
if (narg < 4 || narg > 6)
error->all(FLERR,"Incorrect 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 a0_one = utils::numeric(FLERR,arg[2],false,lmp);
double gamma_one = utils::numeric(FLERR,arg[3],false,lmp);
double cut_one = cut_global;
double cut_two = 0.0;
if (narg > 4) {
bool do_slater = utils::logical(FLERR,arg[4],false,lmp);
if (do_slater) cut_two = cut_coul+2.0*qdist;
}
if (narg > 5) cut_one = utils::numeric(FLERR,arg[5],false,lmp);
int count = 0;
for (int i = ilo; i <= ihi; i++) {
for (int j = MAX(jlo,i); j <= jhi; j++) {
a0[i][j] = a0_one;
gamma[i][j] = gamma_one;
cut_dpd[i][j] = cut_one;
cut_slater[i][j] = cut_two;
cut[i][j] = MAX(cut_one, cut_two);
setflag[i][j] = 1;
scale[i][j] = 1.0;
count++;
}
}
if (count == 0) error->all(FLERR,"Incorrect args for pair coefficients");
}
/* ----------------------------------------------------------------------
init specific to this pair style
------------------------------------------------------------------------- */
void PairDPDCharged::init_style()
{
if (comm->ghost_velocity == 0)
error->all(FLERR,"Pair dpd requires ghost atoms store velocity");
if (!atom->q_flag)
error->all(FLERR,"Pair style coul/slater/long requires atom attribute q");
// if newton off, forces between atoms ij will be double computed
// using different random numbers
if (force->newton_pair == 0 && comm->me == 0)
error->warning(FLERR, "Pair dpd needs newton pair on for momentum conservation");
neighbor->add_request(this);
// precompute random force scaling factors
for (int i = 0; i < 4; ++i) special_sqrt[i] = sqrt(force->special_lj[i]);
// ensure use of KSpace long-range solver, set g_ewald
if (force->kspace == nullptr)
error->all(FLERR,"Pair style requires a KSpace style");
g_ewald = force->kspace->g_ewald;
}
/* ----------------------------------------------------------------------
init for one type pair i,j and corresponding j,i
return the maximum cutoff between Slater or DPD cutoff if charged
return the DPD cutoff for uncharged
------------------------------------------------------------------------- */
double PairDPDCharged::init_one(int i, int j)
{
if (setflag[i][j] == 0) error->all(FLERR,"All pair coeffs are not set");
sigma[i][j] = sqrt(2.0*force->boltz*temperature*gamma[i][j]);
cut_dpdsq[i][j] = cut_dpd[i][j] * cut_dpd[i][j];
cut_dpdsq[j][i] = cut_dpdsq[i][j];
cut_slatersq[i][j] = cut_slater[i][j] * cut_slater[i][j];
cut_slatersq[j][i] = cut_slatersq[i][j];
a0[j][i] = a0[i][j];
gamma[j][i] = gamma[i][j];
sigma[j][i] = sigma[i][j];
scale[j][i] = scale[i][j];
cut_dpd[j][i] = cut_dpd[i][j];
cut_slater[j][i] = cut_slater[i][j];
cut[j][i] = cut[i][j];
//return cut[i][j];
return MAX(cut_dpd[i][j], cut_slater[i][j]);
}
/* ----------------------------------------------------------------------
proc 0 writes to restart file
------------------------------------------------------------------------- */
void PairDPDCharged::write_restart(FILE *fp)
{
write_restart_settings(fp);
int i,j;
for (i = 1; i <= atom->ntypes; i++)
for (j = i; j <= atom->ntypes; j++) {
fwrite(&setflag[i][j],sizeof(int),1,fp);
if (setflag[i][j]) {
fwrite(&a0[i][j],sizeof(double),1,fp);
fwrite(&gamma[i][j],sizeof(double),1,fp);
fwrite(&cut[i][j],sizeof(double),1,fp);
fwrite(&cut_dpd[i][j],sizeof(double),1,fp);
fwrite(&cut_dpdsq[i][j],sizeof(double),1,fp);
fwrite(&cut_slater[i][j],sizeof(double),1,fp);
fwrite(&cut_slatersq[i][j],sizeof(double),1,fp);
fwrite(&scale[i][j],sizeof(double),1,fp);
}
}
}
/* ----------------------------------------------------------------------
proc 0 reads from restart file, bcasts
------------------------------------------------------------------------- */
void PairDPDCharged::read_restart(FILE *fp)
{
read_restart_settings(fp);
allocate();
int i,j;
int me = comm->me;
for (i = 1; i <= atom->ntypes; i++)
for (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,&a0[i][j],sizeof(double),1,fp,nullptr,error);
utils::sfread(FLERR,&gamma[i][j],sizeof(double),1,fp,nullptr,error);
utils::sfread(FLERR,&cut[i][j],sizeof(double),1,fp,nullptr,error);
utils::sfread(FLERR, &scale[i][j],sizeof(double),1,fp, nullptr, error);
}
MPI_Bcast(&a0[i][j],1,MPI_DOUBLE,0,world);
MPI_Bcast(&gamma[i][j],1,MPI_DOUBLE,0,world);
MPI_Bcast(&cut[i][j],1,MPI_DOUBLE,0,world);
MPI_Bcast(&cut_dpd[i][j],1,MPI_DOUBLE,0,world);
MPI_Bcast(&cut_dpdsq[i][j],1,MPI_DOUBLE,0,world);
MPI_Bcast(&cut_slater[i][j],1,MPI_DOUBLE,0,world);
MPI_Bcast(&cut_slatersq[i][j],1,MPI_DOUBLE,0,world);
MPI_Bcast(&scale[i][j],1,MPI_DOUBLE,0,world);
}
}
}
/* ----------------------------------------------------------------------
proc 0 writes to restart file
------------------------------------------------------------------------- */
void PairDPDCharged::write_restart_settings(FILE *fp)
{
fwrite(&temperature,sizeof(double),1,fp);
fwrite(&cut_global,sizeof(double),1,fp);
fwrite(&seed,sizeof(int),1,fp);
fwrite(&mix_flag,sizeof(int),1,fp);
fwrite(&cut_coul,sizeof(double),1,fp);
fwrite(&cut_dpd,sizeof(double),1,fp);
fwrite(&cut_dpdsq,sizeof(double),1,fp);
fwrite(&cut_slater,sizeof(double),1,fp);
fwrite(&cut_slatersq,sizeof(double),1,fp);
fwrite(&lamda,sizeof(double),1,fp);
fwrite(&offset_flag,sizeof(int),1,fp);
}
/* ----------------------------------------------------------------------
proc 0 reads from restart file, bcasts
------------------------------------------------------------------------- */
void PairDPDCharged::read_restart_settings(FILE *fp)
{
if (comm->me == 0) {
utils::sfread(FLERR,&temperature,sizeof(double),1,fp,nullptr,error);
utils::sfread(FLERR,&cut_global,sizeof(double),1,fp,nullptr,error);
utils::sfread(FLERR,&seed,sizeof(int),1,fp,nullptr,error);
utils::sfread(FLERR,&mix_flag,sizeof(int),1,fp,nullptr,error);
utils::sfread(FLERR, &cut_coul,sizeof(double),1,fp,nullptr,error);
utils::sfread(FLERR, &cut_dpd,sizeof(double),1,fp,nullptr,error);
utils::sfread(FLERR, &cut_dpdsq,sizeof(double),1,fp,nullptr,error);
utils::sfread(FLERR, &cut_slater,sizeof(double),1,fp,nullptr,error);
utils::sfread(FLERR, &cut_slatersq,sizeof(double),1,fp,nullptr,error);
utils::sfread(FLERR, &lamda,sizeof(double),1,fp,nullptr,error);
utils::sfread(FLERR, &offset_flag,sizeof(int),1,fp,nullptr,error);
}
MPI_Bcast(&temperature,1,MPI_DOUBLE,0,world);
MPI_Bcast(&cut_global,1,MPI_DOUBLE,0,world);
MPI_Bcast(&seed,1,MPI_INT,0,world);
MPI_Bcast(&mix_flag,1,MPI_INT,0,world);
MPI_Bcast(&cut_coul,1,MPI_DOUBLE,0,world);
MPI_Bcast(&lamda,1,MPI_DOUBLE,0,world);
MPI_Bcast(&offset_flag,1,MPI_INT,0,world);
// initialize Marsaglia RNG with processor-unique seed
// same seed that pair_style command initially specified
if (random) delete random;
random = new RanMars(lmp,seed + comm->me);
}
/* ----------------------------------------------------------------------
proc 0 writes to data file
------------------------------------------------------------------------- */
void PairDPDCharged::write_data(FILE *fp)
{
for (int i = 1; i <= atom->ntypes; i++)
fprintf(fp,"%d %g %g\n",i,a0[i][i],gamma[i][i]);
}
/* ----------------------------------------------------------------------
proc 0 writes all pairs to data file
------------------------------------------------------------------------- */
void PairDPDCharged::write_data_all(FILE *fp)
{
for (int i = 1; i <= atom->ntypes; i++)
for (int j = i; j <= atom->ntypes; j++)
fprintf(fp,"%d %d %g %g %g\n",i,j,a0[i][j],gamma[i][j],cut[i][j]);
}
/* ---------------------------------------------------------------------- */
double PairDPDCharged::single(int i, int j, int itype, int jtype, double rsq,
double factor_coul, double factor_dpd, double &fforce)
{
double r,rinv,wd,phi;
double r2inv,grij,expm2,t,erfc,prefactor;
double slater_term;
double forcecoul,phicoul;
double energy = 0.0;
fforce = 0.0;
r = sqrt(rsq);
// compute DPD force and energy
if (rsq < cut_dpdsq[itype][jtype] && r > EPSILON) {
rinv = 1.0/r;
wd = 1.0 - r/cut_dpd[itype][jtype];
fforce += a0[itype][jtype]*wd * factor_dpd*rinv;
phi = 0.5*a0[itype][jtype]*cut_dpd[itype][jtype] * wd*wd;
energy += factor_dpd*phi;
}
// compute Slater coulombic force and energy
if (atom->q[i]*atom->q[j] != 0.0 && rsq < cut_slatersq[itype][jtype]) {
r2inv = 1.0/rsq;
grij = g_ewald * r;
expm2 = exp(-grij*grij);
t = 1.0 / (1.0 + EWALD_P*grij);
erfc = t * (A1+t*(A2+t*(A3+t*(A4+t*A5)))) * expm2;
slater_term = exp(-2*r/lamda)*(1 + (2*r/lamda*(1+r/lamda)));
prefactor = force->qqrd2e * atom->q[i]*atom->q[j]/r;
forcecoul = prefactor * (erfc + EWALD_F*grij*expm2 - slater_term);
if (factor_coul < 1.0) forcecoul -= (1.0-factor_coul)*prefactor;
fforce += forcecoul * r2inv;
phicoul = prefactor*(erfc - (1 + r/lamda)*exp(-2*r/lamda));
if (factor_coul < 1.0) phicoul -= (1.0-factor_coul)*prefactor;
energy += phicoul;
}
return energy;
}
void *PairDPDCharged::extract(const char *str, int &dim)
{
if (strcmp(str,"cut_coul") == 0) {
dim = 0;
return (void *) &cut_coul;
}
if (strcmp(str,"lamda") == 0) {
dim = 0;
return (void *) &lamda;
}
if (strcmp(str,"scale") == 0) {
dim = 2;
return (void *) scale;
}
return nullptr;
}

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/* -*- 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.
------------------------------------------------------------------------- */
#ifdef PAIR_CLASS
// clang-format off
PairStyle(dpd/charged,PairDPDCharged);
// clang-format on
#else
#ifndef LMP_PAIR_DPD_CHARGED_H
#define LMP_PAIR_DPD_CHARGED_H
#include "pair.h"
namespace LAMMPS_NS {
class PairDPDCharged : public Pair {
public:
PairDPDCharged(class LAMMPS *);
~PairDPDCharged() override;
void compute(int, int) override;
void settings(int, char **) override;
void coeff(int, char **) override;
void init_style() override;
double init_one(int, int) override;
void write_restart(FILE *) override;
void read_restart(FILE *) override;
void write_restart_settings(FILE *) override;
void read_restart_settings(FILE *) override;
void write_data(FILE *) override;
void write_data_all(FILE *) override;
double single(int, int, int, int, double, double, double, double &) override;
void *extract(const char *, int &) override;
protected:
double cut_global, temperature;
double special_sqrt[4];
int seed;
double **cut;
double **cut_dpd, **cut_dpdsq;
double **cut_slater, **cut_slatersq;
double **a0, **gamma;
double **sigma;
class RanMars *random;
double cut_coul, qdist;
double lamda;
double g_ewald;
double **scale;
virtual void allocate();
};
} // namespace LAMMPS_NS
#endif
#endif

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/* ----------------------------------------------------------------------
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: Trung Dac Nguyen (ORNL)
------------------------------------------------------------------------- */
#include "pair_dpd_charged_gpu.h"
#include "atom.h"
#include "domain.h"
#include "error.h"
#include "force.h"
#include "gpu_extra.h"
#include "neigh_list.h"
#include "neighbor.h"
#include "suffix.h"
#include "update.h"
#include "ewald_const.h"
#include "kspace.h"
#include <cmath>
#include <cstring>
using namespace LAMMPS_NS;
using namespace EwaldConst;
// External functions from cuda library for atom decomposition
int dpd_charged_gpu_init(const int ntypes, double **cutsq, double **host_a0, double **host_gamma,
double **host_sigma, double **host_cut, double *special_lj, const int inum,
const int nall, const int max_nbors, const int maxspecial, const double cell_size,
int &gpu_mode, FILE *screen);
void dpd_charged_gpu_clear();
int **dpd_charged_gpu_compute_n(const int ago, const int inum_full, const int nall, double **host_x,
int *host_type, double *sublo, double *subhi, tagint *tag, int **nspecial,
tagint **special, const bool eflag, const bool vflag, const bool eatom,
const bool vatom, int &host_start, int **ilist, int **jnum,
const double cpu_time, bool &success, double **host_v,
const double dtinvsqrt, const int seed, const int timestep, double *boxlo,
double *prd);
void dpd_charged_gpu_compute(const int ago, const int inum_full, const int nall, double **host_x,
int *host_type, int *ilist, int *numj, int **firstneigh, const bool eflag,
const bool vflag, const bool eatom, const bool vatom, int &host_start,
const double cpu_time, bool &success, tagint *tag, double **host_v,
const double dtinvsqrt, const int seed, const int timestep, const int nlocal,
double *boxlo, double *prd);
double dpd_charged_gpu_bytes();
static constexpr double EPSILON = 1.0e-10;
//#define _USE_UNIFORM_SARU_LCG
//#define _USE_UNIFORM_SARU_TEA8
//#define _USE_GAUSSIAN_SARU_LCG
#if !defined(_USE_UNIFORM_SARU_LCG) && !defined(_USE_UNIFORM_SARU_TEA8) && \
!defined(_USE_GAUSSIAN_SARU_LCG)
#define _USE_UNIFORM_SARU_LCG
#endif
// References:
// 1. Y. Afshar, F. Schmid, A. Pishevar, S. Worley, Comput. Phys. Comm. 184 (2013), 1119–1128.
// 2. C. L. Phillips, J. A. Anderson, S. C. Glotzer, Comput. Phys. Comm. 230 (2011), 7191-7201.
// PRNG period = 3666320093*2^32 ~ 2^64 ~ 10^19
#define LCGA 0x4beb5d59 // Full period 32 bit LCG
#define LCGC 0x2600e1f7
#define oWeylPeriod 0xda879add // Prime period 3666320093
#define oWeylOffset 0x8009d14b
#define TWO_N32 0.232830643653869628906250e-9f /* 2^-32 */
// specifically implemented for steps = 1; high = 1.0; low = -1.0
// returns uniformly distributed random numbers u in [-1.0;1.0]
// using the inherent LCG, then multiply u with sqrt(3) to "match"
// with a normal random distribution.
// Afshar et al. mutlplies u in [-0.5;0.5] with sqrt(12)
// Curly brackets to make variables local to the scope.
#ifdef _USE_UNIFORM_SARU_LCG
#define numtyp double
#define SQRT3 (numtyp) 1.7320508075688772935274463
#define saru(seed1, seed2, seed, timestep, randnum) \
{ \
unsigned int seed3 = seed + timestep; \
seed3 ^= (seed1 << 7) ^ (seed2 >> 6); \
seed2 += (seed1 >> 4) ^ (seed3 >> 15); \
seed1 ^= (seed2 << 9) + (seed3 << 8); \
seed3 ^= 0xA5366B4D * ((seed2 >> 11) ^ (seed1 << 1)); \
seed2 += 0x72BE1579 * ((seed1 << 4) ^ (seed3 >> 16)); \
seed1 ^= 0x3F38A6ED * ((seed3 >> 5) ^ (((signed int) seed2) >> 22)); \
seed2 += seed1 * seed3; \
seed1 += seed3 ^ (seed2 >> 2); \
seed2 ^= ((signed int) seed2) >> 17; \
unsigned int state = 0x79dedea3 * (seed1 ^ (((signed int) seed1) >> 14)); \
unsigned int wstate = (state + seed2) ^ (((signed int) state) >> 8); \
state = state + (wstate * (wstate ^ 0xdddf97f5)); \
wstate = 0xABCB96F7 + (wstate >> 1); \
state = LCGA * state + LCGC; \
wstate = wstate + oWeylOffset + ((((signed int) wstate) >> 31) & oWeylPeriod); \
unsigned int v = (state ^ (state >> 26)) + wstate; \
unsigned int s = (signed int) ((v ^ (v >> 20)) * 0x6957f5a7); \
randnum = SQRT3 * (s * TWO_N32 * (numtyp) 2.0 - (numtyp) 1.0); \
}
#endif
// specifically implemented for steps = 1; high = 1.0; low = -1.0
// returns uniformly distributed random numbers u in [-1.0;1.0] using TEA8
// then multiply u with sqrt(3) to "match" with a normal random distribution
// Afshar et al. mutlplies u in [-0.5;0.5] with sqrt(12)
#ifdef _USE_UNIFORM_SARU_TEA8
#define numtyp double
#define SQRT3 (numtyp) 1.7320508075688772935274463
#define k0 0xA341316C
#define k1 0xC8013EA4
#define k2 0xAD90777D
#define k3 0x7E95761E
#define delta 0x9e3779b9
#define rounds 8
#define saru(seed1, seed2, seed, timestep, randnum) \
{ \
unsigned int seed3 = seed + timestep; \
seed3 ^= (seed1 << 7) ^ (seed2 >> 6); \
seed2 += (seed1 >> 4) ^ (seed3 >> 15); \
seed1 ^= (seed2 << 9) + (seed3 << 8); \
seed3 ^= 0xA5366B4D * ((seed2 >> 11) ^ (seed1 << 1)); \
seed2 += 0x72BE1579 * ((seed1 << 4) ^ (seed3 >> 16)); \
seed1 ^= 0x3F38A6ED * ((seed3 >> 5) ^ (((signed int) seed2) >> 22)); \
seed2 += seed1 * seed3; \
seed1 += seed3 ^ (seed2 >> 2); \
seed2 ^= ((signed int) seed2) >> 17; \
unsigned int state = 0x79dedea3 * (seed1 ^ (((signed int) seed1) >> 14)); \
unsigned int wstate = (state + seed2) ^ (((signed int) state) >> 8); \
state = state + (wstate * (wstate ^ 0xdddf97f5)); \
wstate = 0xABCB96F7 + (wstate >> 1); \
unsigned int sum = 0; \
for (int i = 0; i < rounds; i++) { \
sum += delta; \
state += ((wstate << 4) + k0) ^ (wstate + sum) ^ ((wstate >> 5) + k1); \
wstate += ((state << 4) + k2) ^ (state + sum) ^ ((state >> 5) + k3); \
} \
unsigned int v = (state ^ (state >> 26)) + wstate; \
unsigned int s = (signed int) ((v ^ (v >> 20)) * 0x6957f5a7); \
randnum = SQRT3 * (s * TWO_N32 * (numtyp) 2.0 - (numtyp) 1.0); \
}
#endif
// specifically implemented for steps = 1; high = 1.0; low = -1.0
// returns two uniformly distributed random numbers r1 and r2 in [-1.0;1.0],
// and uses the polar method (Marsaglia's) to transform to a normal random value
// This is used to compared with CPU DPD using RandMars::gaussian()
#ifdef _USE_GAUSSIAN_SARU_LCG
#define numtyp double
#define saru(seed1, seed2, seed, timestep, randnum) \
{ \
unsigned int seed3 = seed + timestep; \
seed3 ^= (seed1 << 7) ^ (seed2 >> 6); \
seed2 += (seed1 >> 4) ^ (seed3 >> 15); \
seed1 ^= (seed2 << 9) + (seed3 << 8); \
seed3 ^= 0xA5366B4D * ((seed2 >> 11) ^ (seed1 << 1)); \
seed2 += 0x72BE1579 * ((seed1 << 4) ^ (seed3 >> 16)); \
seed1 ^= 0x3F38A6ED * ((seed3 >> 5) ^ (((signed int) seed2) >> 22)); \
seed2 += seed1 * seed3; \
seed1 += seed3 ^ (seed2 >> 2); \
seed2 ^= ((signed int) seed2) >> 17; \
unsigned int state = 0x12345678; \
unsigned int wstate = 12345678; \
state = 0x79dedea3 * (seed1 ^ (((signed int) seed1) >> 14)); \
wstate = (state + seed2) ^ (((signed int) state) >> 8); \
state = state + (wstate * (wstate ^ 0xdddf97f5)); \
wstate = 0xABCB96F7 + (wstate >> 1); \
unsigned int v, s; \
numtyp r1, r2, rsq; \
while (1) { \
state = LCGA * state + LCGC; \
wstate = wstate + oWeylOffset + ((((signed int) wstate) >> 31) & oWeylPeriod); \
v = (state ^ (state >> 26)) + wstate; \
s = (signed int) ((v ^ (v >> 20)) * 0x6957f5a7); \
r1 = s * TWO_N32 * (numtyp) 2.0 - (numtyp) 1.0; \
state = LCGA * state + LCGC; \
wstate = wstate + oWeylOffset + ((((signed int) wstate) >> 31) & oWeylPeriod); \
v = (state ^ (state >> 26)) + wstate; \
s = (signed int) ((v ^ (v >> 20)) * 0x6957f5a7); \
r2 = s * TWO_N32 * (numtyp) 2.0 - (numtyp) 1.0; \
rsq = r1 * r1 + r2 * r2; \
if (rsq < (numtyp) 1.0) break; \
} \
numtyp fac = sqrt((numtyp) -2.0 * log(rsq) / rsq); \
randnum = r2 * fac; \
}
#endif
/* ---------------------------------------------------------------------- */
PairDPDChargedGPU::PairDPDCharged(LAMMPS *lmp) : PairDPD(lmp), gpu_mode(GPU_FORCE)
{
respa_enable = 0;
reinitflag = 0;
cpu_time = 0.0;
suffix_flag |= Suffix::GPU;
GPU_EXTRA::gpu_ready(lmp->modify, lmp->error);
}
/* ----------------------------------------------------------------------
free all arrays
------------------------------------------------------------------------- */
PairDPDChargedGPU::~PairDPDChargedGPU()
{
dpd_charged_gpu_clear();
}
/* ---------------------------------------------------------------------- */
void PairDPDChargedGPU::compute(int eflag, int vflag)
{
ev_init(eflag, vflag);
int nall = atom->nlocal + atom->nghost;
int inum, host_start;
double dtinvsqrt = 1.0 / sqrt(update->dt);
bool success = true;
int *ilist, *numneigh, **firstneigh;
if (gpu_mode != GPU_FORCE) {
double sublo[3], subhi[3];
if (domain->triclinic == 0) {
sublo[0] = domain->sublo[0];
sublo[1] = domain->sublo[1];
sublo[2] = domain->sublo[2];
subhi[0] = domain->subhi[0];
subhi[1] = domain->subhi[1];
subhi[2] = domain->subhi[2];
} else {
domain->bbox(domain->sublo_lamda, domain->subhi_lamda, sublo, subhi);
}
inum = atom->nlocal;
firstneigh = dpd_charged_gpu_compute_n(
neighbor->ago, inum, nall, atom->x, atom->type, sublo, subhi, atom->tag, atom->nspecial,
atom->special, eflag, vflag, eflag_atom, vflag_atom, host_start, &ilist, &numneigh,
cpu_time, success, atom->v, dtinvsqrt, seed, update->ntimestep, domain->boxlo, domain->prd);
} else {
inum = list->inum;
ilist = list->ilist;
numneigh = list->numneigh;
firstneigh = list->firstneigh;
dpd_charged_gpu_compute(neighbor->ago, inum, nall, atom->x, atom->type, ilist, numneigh, firstneigh,
eflag, vflag, eflag_atom, vflag_atom, host_start, cpu_time, success, atom->tag,
atom->v, dtinvsqrt, seed, update->ntimestep, atom->nlocal, domain->boxlo,
domain->prd);
}
if (!success) error->one(FLERR, "Insufficient memory on accelerator");
if (atom->molecular != Atom::ATOMIC && neighbor->ago == 0)
neighbor->build_topology();
if (host_start < inum) {
cpu_time = platform::walltime();
cpu_compute(host_start, inum, eflag, vflag, ilist, numneigh, firstneigh);
cpu_time = platform::walltime() - cpu_time;
}
}
/* ----------------------------------------------------------------------
init specific to this pair style
------------------------------------------------------------------------- */
void PairDPDChargedGPU::init_style()
{
// Repeat cutsq calculation because done after call to init_style
double maxcut = -1.0;
double mcut;
for (int i = 1; i <= atom->ntypes; i++) {
for (int j = i; j <= atom->ntypes; j++) {
if (setflag[i][j] != 0 || (setflag[i][i] != 0 && setflag[j][j] != 0)) {
mcut = init_one(i, j);
mcut *= mcut;
if (mcut > maxcut) maxcut = mcut;
cutsq[i][j] = cutsq[j][i] = mcut;
} else
cutsq[i][j] = cutsq[j][i] = 0.0;
}
}
double cell_size = sqrt(maxcut) + neighbor->skin;
int maxspecial = 0;
if (atom->molecular != Atom::ATOMIC) maxspecial = atom->maxspecial;
int mnf = 5e-2 * neighbor->oneatom;
int success =
dpd_charged_gpu_init(atom->ntypes + 1, cutsq, a0, gamma, sigma, cut, force->special_lj, atom->nlocal,
atom->nlocal + atom->nghost, mnf, maxspecial, cell_size, gpu_mode, screen);
GPU_EXTRA::check_flag(success, error, world);
if (gpu_mode == GPU_FORCE) neighbor->add_request(this, NeighConst::REQ_FULL);
}
/* ---------------------------------------------------------------------- */
double PairDPDChargedGPU::memory_usage()
{
double bytes = Pair::memory_usage();
return bytes + dpd_charged_gpu_bytes();
}
/* ---------------------------------------------------------------------- */
void PairDPDChargedGPU::cpu_compute(int start, int inum, int eflag, int /* vflag */, int *ilist,
int *numneigh, int **firstneigh)
{
int i, j, ii, jj, jnum, itype, jtype;
double xtmp, ytmp, ztmp, delx, dely, delz, evdwl, fpair;
double vxtmp, vytmp, vztmp, delvx, delvy, delvz;
double r2inv,forcedpd,forcecoul,factor_coul;
double grij,expm2,prefactor,t,erfc;
double rsq,r,rinv,dot,wd,randnum,factor_dpd,factor_sqrt;
int *ilist,*jlist,*numneigh,**firstneigh;
double slater_term;
int *jlist;
tagint itag, jtag;
double *q = atom->q;
double *special_coul = force->special_coul;
double qqrd2e = force->qqrd2e;
evdwl = 0.0;
ecoul = 0.0;
double **x = atom->x;
double **v = atom->v;
double **f = atom->f;
int *type = atom->type;
tagint *tag = atom->tag;
double *special_lj = force->special_lj;
double dtinvsqrt = 1.0 / sqrt(update->dt);
int timestep = (int) update->ntimestep;
// loop over neighbors of my atoms
for (ii = start; ii < inum; ii++) {
i = ilist[ii];
qtmp = q[i];
xtmp = x[i][0];
ytmp = x[i][1];
ztmp = x[i][2];
vxtmp = v[i][0];
vytmp = v[i][1];
vztmp = v[i][2];
itype = type[i];
itag = tag[i];
jlist = firstneigh[i];
jnum = numneigh[i];
for (jj = 0; jj < jnum; jj++) {
j = jlist[jj];
factor_dpd = special_lj[sbmask(j)];
factor_sqrt = special_sqrt[sbmask(j)];
factor_coul = special_coul[sbmask(j)];
j &= NEIGHMASK;
delx = xtmp - x[j][0];
dely = ytmp - x[j][1];
delz = ztmp - x[j][2];
rsq = delx * delx + dely * dely + delz * delz;
jtype = type[j];
jtag = tag[j];
// forces if below maximum cutoff
if (rsq < cutsq[itype][jtype]) {
r = sqrt(rsq);
if (r < EPSILON) continue; // r can be 0.0 in DPD systems
// apply DPD force if distance below DPD cutoff
if (rsq < cut_dpdsq[itype][jtype]) {
rinv = 1.0 / r;
delvx = vxtmp - v[j][0];
delvy = vytmp - v[j][1];
delvz = vztmp - v[j][2];
dot = delx * delvx + dely * delvy + delz * delvz;
wd = 1.0 - r / cut[itype][jtype];
unsigned int tag1 = itag, tag2 = jtag;
if (tag1 > tag2) {
tag1 = jtag;
tag2 = itag;
}
randnum = 0.0;
saru(tag1, tag2, seed, timestep, randnum);
// conservative force = a0 * wd
// drag force = -gamma * wd^2 * (delx dot delv) / r
// random force = sigma * wd * rnd * dtinvsqrt;
forcedpd = a0[itype][jtype]*wd;
forcedpd -= gamma[itype][jtype]*wd*wd*dot*rinv;
forcedpd *= factor_dpd;
forcedpd += factor_sqrt*sigma[itype][jtype]*wd*randnum*dtinvsqrt;
forcedpd *= rinv;
} else forcedpd = 0.0;
// apply Slater electrostatic force if distance below Slater cutoff
// and the two species are charged
if (cut_slater[itype][jtype] != 0.0 && rsq < cut_slatersq[itype][jtype]){
r2inv = 1.0/rsq;
grij = g_ewald * r;
expm2 = exp(-grij*grij);
t = 1.0 / (1.0 + EWALD_P*grij);
erfc = t * (A1+t*(A2+t*(A3+t*(A4+t*A5)))) * expm2;
slater_term = exp(-2*r/lamda)*(1 + (2*r/lamda*(1+r/lamda)));
prefactor = qqrd2e * scale[itype][jtype] * qtmp*q[j]/r;
forcecoul = prefactor * (erfc + EWALD_F*grij*expm2 - slater_term);
if (factor_coul < 1.0) forcecoul -= (1.0-factor_coul)*prefactor*(1-slater_term);
forcecoul *= r2inv;
} else forcecoul = 0.0;
f[i][0] += delx * fpair;
f[i][1] += dely * fpair;
f[i][2] += delz * fpair;
if (eflag) {
// unshifted eng of conservative term:
// evdwl = -a0[itype][jtype]*r * (1.0-0.5*r/cut[itype][jtype]);
// eng shifted to 0.0 at cutoff
evdwl = 0.5 * a0[itype][jtype] * cut[itype][jtype] * wd * wd;
evdwl *= factor_dpd;
}
if (evflag) ev_tally_full(i, evdwl, 0.0, fpair, delx, dely, delz);
}
}
}
}

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src/GPU/pair_dpd_charged_gpu.h Normal file
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/* -*- 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.
------------------------------------------------------------------------- */
#ifdef PAIR_CLASS
// clang-format off
PairStyle(dpd/charged/gpu,PairDPDChargedGPU);
// clang-format on
#else
#ifndef LMP_PAIR_DPD_CHARGED_GPU_H
#define LMP_PAIR_DPD_CHARGED_GPU_H
#include "pair_dpd_charged.h"
namespace LAMMPS_NS {
class PairDPDChargedGPU : public PairDPDCharged {
public:
PairDPDChargedGPU(LAMMPS *lmp);
~PairDPDChargedGPU() override;
void cpu_compute(int, int, int, int, int *, int *, int **);
void compute(int, int) override;
void init_style() override;
double memory_usage() override;
enum { GPU_FORCE, GPU_NEIGH, GPU_HYB_NEIGH };
private:
int gpu_mode;
double cpu_time;
};
} // namespace LAMMPS_NS
#endif
#endif