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lal_coul_dsf.cu
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rLAMMPS lammps
lal_coul_dsf.cu
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// **************************************************************************
// coul_dsf.cu
// -------------------
// Trung Dac Nguyen (ORNL)
//
// Device code for acceleration of the coul/dsf pair style
//
// __________________________________________________________________________
// This file is part of the LAMMPS Accelerator Library (LAMMPS_AL)
// __________________________________________________________________________
//
// begin : 8/15/2012
// email : nguyentd@ornl.gov
// ***************************************************************************/
#ifdef NV_KERNEL
#include "lal_aux_fun1.h"
#ifndef _DOUBLE_DOUBLE
texture<float4> pos_tex;
texture<float> q_tex;
#else
texture<int4,1> pos_tex;
texture<int2> q_tex;
#endif
#else
#define pos_tex x_
#define q_tex q_
#endif
#define MY_PIS (acctyp)1.77245385090551602729
__kernel void k_coul_dsf(const __global numtyp4 *restrict x_,
const int lj_types,
const __global numtyp *restrict sp_lj_in,
const __global int *dev_nbor,
const __global int *dev_packed,
__global acctyp4 *restrict ans,
__global acctyp *restrict engv,
const int eflag, const int vflag, const int inum,
const int nbor_pitch,
const __global numtyp *restrict q_ ,
const numtyp cut_coulsq, const numtyp qqrd2e,
const numtyp e_shift, const numtyp f_shift,
const numtyp alpha, const int t_per_atom) {
int tid, ii, offset;
atom_info(t_per_atom,ii,tid,offset);
__local numtyp sp_lj[4];
sp_lj[0]=sp_lj_in[0];
sp_lj[1]=sp_lj_in[1];
sp_lj[2]=sp_lj_in[2];
sp_lj[3]=sp_lj_in[3];
acctyp energy=(acctyp)0;
acctyp e_coul=(acctyp)0;
acctyp4 f;
f.x=(acctyp)0; f.y=(acctyp)0; f.z=(acctyp)0;
acctyp virial[6];
for (int i=0; i<6; i++)
virial[i]=(acctyp)0;
if (ii<inum) {
int nbor, nbor_end;
int i, numj;
__local int n_stride;
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];
numtyp qtmp; fetch(qtmp,i,q_tex);
if (eflag>0) {
acctyp e_self = -((acctyp)0.5*e_shift + alpha/MY_PIS) *
qtmp*qtmp*qqrd2e/(acctyp)t_per_atom;
e_coul += (acctyp)2.0*e_self;
}
for ( ; nbor<nbor_end; nbor+=n_stride) {
int j=dev_packed[nbor];
numtyp factor_coul, r, prefactor, erfcc;
factor_coul = sp_lj[sbmask(j)];
j &= NEIGHMASK;
numtyp4 jx; fetch4(jx,j,pos_tex); //x_[j];
// 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 < cut_coulsq) {
numtyp r2inv=ucl_recip(rsq);
numtyp forcecoul, force;
r = ucl_sqrt(rsq);
fetch(prefactor,j,q_tex);
prefactor *= factor_coul * qqrd2e*qtmp/r;
numtyp erfcd = ucl_exp(-alpha*alpha*rsq);
numtyp t = ucl_recip((numtyp)1.0 + EWALD_P*alpha*r);
erfcc = t * (A1+t*(A2+t*(A3+t*(A4+t*A5)))) * erfcd;
forcecoul = prefactor * (erfcc + (numtyp)2.0*alpha/MY_PIS*r*erfcd +
rsq*f_shift);
force = forcecoul * r2inv;
f.x+=delx*force;
f.y+=dely*force;
f.z+=delz*force;
if (eflag>0) {
if (rsq < cut_coulsq) {
numtyp e=prefactor*(erfcc-r*e_shift-rsq*f_shift);
e_coul += e;
}
}
if (vflag>0) {
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
store_answers_q(f,energy,e_coul,virial,ii,inum,tid,t_per_atom,offset,eflag,
vflag,ans,engv);
} // if ii
}
__kernel void k_coul_dsf_fast(const __global numtyp4 *restrict x_,
const __global numtyp *restrict sp_lj_in,
const __global int *dev_nbor,
const __global int *dev_packed,
__global acctyp4 *restrict ans,
__global acctyp *restrict engv,
const int eflag, const int vflag, const int inum,
const int nbor_pitch,
const __global numtyp *restrict q_,
const numtyp cut_coulsq, const numtyp qqrd2e,
const numtyp e_shift, const numtyp f_shift,
const numtyp alpha, const int t_per_atom) {
int tid, ii, offset;
atom_info(t_per_atom,ii,tid,offset);
__local numtyp sp_lj[4];
if (tid<4)
sp_lj[tid]=sp_lj_in[tid];
acctyp energy=(acctyp)0;
acctyp e_coul=(acctyp)0;
acctyp4 f;
f.x=(acctyp)0; f.y=(acctyp)0; f.z=(acctyp)0;
acctyp virial[6];
for (int i=0; i<6; i++)
virial[i]=(acctyp)0;
__syncthreads();
if (ii<inum) {
int nbor, nbor_end;
int i, numj;
__local int n_stride;
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];
numtyp qtmp; fetch(qtmp,i,q_tex);
if (eflag>0) {
acctyp e_self = -((acctyp)0.5*e_shift + alpha/MY_PIS) *
qtmp*qtmp*qqrd2e/(acctyp)t_per_atom;
e_coul += (acctyp)2.0*e_self;
}
for ( ; nbor<nbor_end; nbor+=n_stride) {
int j=dev_packed[nbor];
numtyp factor_coul, r, prefactor, erfcc;
factor_coul = sp_lj[sbmask(j)];
j &= NEIGHMASK;
numtyp4 jx; fetch4(jx,j,pos_tex); //x_[j];
// 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 < cut_coulsq) {
numtyp r2inv=ucl_recip(rsq);
numtyp forcecoul, force;
r = ucl_sqrt(rsq);
fetch(prefactor,j,q_tex);
prefactor *= factor_coul * qqrd2e*qtmp/r;
numtyp erfcd = ucl_exp(-alpha*alpha*rsq);
numtyp t = ucl_recip((numtyp)1.0 + EWALD_P*alpha*r);
erfcc = t * (A1+t*(A2+t*(A3+t*(A4+t*A5)))) * erfcd;
forcecoul = prefactor * (erfcc + (numtyp)2.0*alpha/MY_PIS*r*erfcd +
rsq*f_shift);
force = forcecoul * r2inv;
f.x+=delx*force;
f.y+=dely*force;
f.z+=delz*force;
if (eflag>0) {
if (rsq < cut_coulsq) {
numtyp e=prefactor*(erfcc-r*e_shift-rsq*f_shift);
e_coul += e;
}
}
if (vflag>0) {
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
store_answers_q(f,energy,e_coul,virial,ii,inum,tid,t_per_atom,offset,eflag,
vflag,ans,engv);
} // if ii
}
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