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lammps/lib/gpu/lj.cu
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lj.cu
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// **************************************************************************
// lj.cu
// -------------------
// W. Michael Brown (ORNL)
//
// Device code for acceleration of the lj/cut pair style
//
// __________________________________________________________________________
// This file is part of the LAMMPS Accelerator Library (LAMMPS_AL)
// __________________________________________________________________________
//
// begin :
// email : brownw@ornl.gov
// ***************************************************************************/
#ifdef NV_KERNEL
#include "preprocessor.h"
texture<float4> pos_tex;
#ifndef _DOUBLE_DOUBLE
__inline float4 fetch_pos(const int& i, const float4 *pos)
{ return tex1Dfetch(pos_tex, i); }
#endif
#endif
__kernel void kernel_pair(__global numtyp4 *x_, __global numtyp4 *lj1,
__global numtyp4* lj3, const int lj_types,
__global numtyp *sp_lj_in, __global int *dev_nbor,
__global int *dev_packed, __global acctyp4 *ans,
__global acctyp *engv, const int eflag,
const int vflag, const int inum,
const int nbor_pitch, const int t_per_atom) {
int tid=THREAD_ID_X;
int ii=mul24((int)BLOCK_ID_X,(int)(BLOCK_SIZE_X)/t_per_atom);
ii+=tid/t_per_atom;
int offset=tid%t_per_atom;
__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;
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) {
__global int *nbor=dev_nbor+ii;
int i=*nbor;
nbor+=nbor_pitch;
int numj=*nbor;
nbor+=nbor_pitch;
int n_stride;
__global int *list_end;
if (dev_nbor==dev_packed) {
list_end=nbor+mul24(numj,nbor_pitch);
nbor+=mul24(offset,nbor_pitch);
n_stride=mul24(t_per_atom,nbor_pitch);
} else {
nbor=dev_packed+*nbor;
list_end=nbor+numj;
n_stride=t_per_atom;
nbor+=offset;
}
numtyp4 ix=fetch_pos(i,x_); //x_[i];
int itype=ix.w;
numtyp factor_lj;
for ( ; nbor<list_end; nbor+=n_stride) {
int j=*nbor;
factor_lj = sp_lj[sbmask(j)];
j &= NEIGHMASK;
numtyp4 jx=fetch_pos(j,x_); //x_[j];
int jtype=jx.w;
// Compute r12
numtyp delx = ix.x-jx.x;
numtyp dely = ix.y-jx.y;
numtyp delz = ix.z-jx.z;
numtyp r2inv = delx*delx+dely*dely+delz*delz;
int mtype=itype*lj_types+jtype;
if (r2inv<lj1[mtype].z) {
r2inv=(numtyp)1.0/r2inv;
numtyp r6inv = r2inv*r2inv*r2inv;
numtyp force = r2inv*r6inv*(lj1[mtype].x*r6inv-lj1[mtype].y);
force*=factor_lj;
f.x+=delx*force;
f.y+=dely*force;
f.z+=delz*force;
if (eflag>0) {
numtyp e=r6inv*(lj3[mtype].x*r6inv-lj3[mtype].y);
energy+=factor_lj*(e-lj3[mtype].z);
}
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
} // if ii
// Reduce answers
if (t_per_atom>1) {
__local acctyp red_acc[6][BLOCK_PAIR];
red_acc[0][tid]=f.x;
red_acc[1][tid]=f.y;
red_acc[2][tid]=f.z;
red_acc[3][tid]=energy;
for (unsigned int s=t_per_atom/2; s>0; s>>=1) {
if (offset < s) {
for (int r=0; r<4; r++)
red_acc[r][tid] += red_acc[r][tid+s];
}
}
f.x=red_acc[0][tid];
f.y=red_acc[1][tid];
f.z=red_acc[2][tid];
energy=red_acc[3][tid];
if (vflag>0) {
for (int r=0; r<6; r++)
red_acc[r][tid]=virial[r];
for (unsigned int s=t_per_atom/2; s>0; s>>=1) {
if (offset < s) {
for (int r=0; r<6; r++)
red_acc[r][tid] += red_acc[r][tid+s];
}
}
for (int r=0; r<6; r++)
virial[r]=red_acc[r][tid];
}
}
// Store answers
if (ii<inum && offset==0) {
__global acctyp *ap1=engv+ii;
if (eflag>0) {
*ap1=energy;
ap1+=inum;
}
if (vflag>0) {
for (int i=0; i<6; i++) {
*ap1=virial[i];
ap1+=inum;
}
}
ans[ii]=f;
} // if ii
}
__kernel void kernel_pair_fast(__global numtyp4 *x_, __global numtyp4 *lj1_in,
__global numtyp4* lj3_in,
__global numtyp* sp_lj_in,
__global int *dev_nbor, __global int *dev_packed,
__global acctyp4 *ans, __global acctyp *engv,
const int eflag, const int vflag, const int inum,
const int nbor_pitch, const int t_per_atom) {
int tid=THREAD_ID_X;
int ii=mul24((int)BLOCK_ID_X,(int)(BLOCK_SIZE_X)/t_per_atom);
ii+=tid/t_per_atom;
int offset=tid%t_per_atom;
__local numtyp4 lj1[MAX_SHARED_TYPES*MAX_SHARED_TYPES];
__local numtyp4 lj3[MAX_SHARED_TYPES*MAX_SHARED_TYPES];
__local numtyp sp_lj[4];
if (tid<4)
sp_lj[tid]=sp_lj_in[tid];
if (tid<MAX_SHARED_TYPES*MAX_SHARED_TYPES) {
lj1[tid]=lj1_in[tid];
if (eflag>0)
lj3[tid]=lj3_in[tid];
}
acctyp energy=(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) {
__global int *nbor=dev_nbor+ii;
int i=*nbor;
nbor+=nbor_pitch;
int numj=*nbor;
nbor+=nbor_pitch;
int n_stride;
__global int *list_end;
if (dev_nbor==dev_packed) {
list_end=nbor+mul24(numj,nbor_pitch);
nbor+=mul24(offset,nbor_pitch);
n_stride=mul24(t_per_atom,nbor_pitch);
} else {
nbor=dev_packed+*nbor;
list_end=nbor+numj;
n_stride=t_per_atom;
nbor+=offset;
}
numtyp4 ix=fetch_pos(i,x_); //x_[i];
int iw=ix.w;
int itype=mul24((int)MAX_SHARED_TYPES,iw);
numtyp factor_lj;
for ( ; nbor<list_end; nbor+=n_stride) {
int j=*nbor;
factor_lj = sp_lj[sbmask(j)];
j &= NEIGHMASK;
numtyp4 jx=fetch_pos(j,x_); //x_[j];
int mtype=itype+jx.w;
// Compute r12
numtyp delx = ix.x-jx.x;
numtyp dely = ix.y-jx.y;
numtyp delz = ix.z-jx.z;
numtyp r2inv = delx*delx+dely*dely+delz*delz;
if (r2inv<lj1[mtype].z) {
r2inv=(numtyp)1.0/r2inv;
numtyp r6inv = r2inv*r2inv*r2inv;
numtyp force = factor_lj*r2inv*r6inv*(lj1[mtype].x*r6inv-lj1[mtype].y);
f.x+=delx*force;
f.y+=dely*force;
f.z+=delz*force;
if (eflag>0) {
numtyp e=r6inv*(lj3[mtype].x*r6inv-lj3[mtype].y);
energy+=factor_lj*(e-lj3[mtype].z);
}
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
} // if ii
// Reduce answers
if (t_per_atom>1) {
__local acctyp red_acc[6][BLOCK_PAIR];
red_acc[0][tid]=f.x;
red_acc[1][tid]=f.y;
red_acc[2][tid]=f.z;
red_acc[3][tid]=energy;
for (unsigned int s=t_per_atom/2; s>0; s>>=1) {
if (offset < s) {
for (int r=0; r<4; r++)
red_acc[r][tid] += red_acc[r][tid+s];
}
}
f.x=red_acc[0][tid];
f.y=red_acc[1][tid];
f.z=red_acc[2][tid];
energy=red_acc[3][tid];
if (vflag>0) {
for (int r=0; r<6; r++)
red_acc[r][tid]=virial[r];
for (unsigned int s=t_per_atom/2; s>0; s>>=1) {
if (offset < s) {
for (int r=0; r<6; r++)
red_acc[r][tid] += red_acc[r][tid+s];
}
}
for (int r=0; r<6; r++)
virial[r]=red_acc[r][tid];
}
}
// Store answers
if (ii<inum && offset==0) {
__global acctyp *ap1=engv+ii;
if (eflag>0) {
*ap1=energy;
ap1+=inum;
}
if (vflag>0) {
for (int i=0; i<6; i++) {
*ap1=virial[i];
ap1+=inum;
}
}
ans[ii]=f;
} // if ii*/
}
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