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gb_gpu_kernel_nbor.cu
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Thu, Nov 7, 08:19

gb_gpu_kernel_nbor.cu
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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 authors: Mike Brown (ORNL), brownw@ornl.gov
------------------------------------------------------------------------- */
#ifndef PAIR_GPU_KERNEL_H
#define PAIR_GPU_KERNEL_H
#ifdef NV_KERNEL
#include "nv_kernel_def.h"
#else
#pragma OPENCL EXTENSION cl_khr_fp64: enable
#define GLOBAL_ID_X get_global_id(0)
#define THREAD_ID_X get_local_id(0)
#define BLOCK_ID_X get_group_id(0)
#define BLOCK_SIZE_X get_local_size(0)
#define __syncthreads() barrier(CLK_LOCAL_MEM_FENCE)
#define MAX_SHARED_TYPES 8
#endif
#ifdef _DOUBLE_DOUBLE
#define numtyp double
#define numtyp2 double2
#define numtyp4 double4
#else
#define numtyp float
#define numtyp2 float2
#define numtyp4 float4
#endif
// ---------------------------------------------------------------------------
// Unpack neighbors from dev_ij array into dev_nbor matrix for coalesced access
// -- Only unpack neighbors matching the specified inclusive range of forms
// -- Only unpack neighbors within cutoff
// ---------------------------------------------------------------------------
__kernel void kernel_gb_nbor(__global numtyp4 *x_, __global numtyp2 *cut_form,
const int ntypes, __global int *dev_nbor,
const int nbor_pitch,
const int start, const int inum,
__global int *dev_ij, const int form_low,
const int form_high, const int nall) {
// ii indexes the two interacting particles in gi
int ii=GLOBAL_ID_X+start;
if (ii<inum) {
__global int *nbor=dev_ij+ii;
int i=*nbor;
nbor+=nbor_pitch;
int numj=*nbor;
nbor+=nbor_pitch;
__global int *list_end=nbor+mul24(numj,nbor_pitch);
__global int *packed=dev_nbor+ii+nbor_pitch+nbor_pitch;
numtyp4 ix=x_[i];
int iw=ix.w;
int itype=mul24(iw,ntypes);
int newj=0;
for ( ; nbor<list_end; nbor+=nbor_pitch) {
int j=*nbor;
if (j>=nall)
j%=nall;
numtyp4 jx=x_[j];
int jtype=jx.w;
int mtype=itype+jtype;
numtyp2 cf=cut_form[mtype];
if (cf.y>=form_low && cf.y<=form_high) {
// Compute r12;
numtyp rsq=jx.x-ix.x;
rsq*=rsq;
numtyp t=jx.y-ix.y;
rsq+=t*t;
t=jx.z-ix.z;
rsq+=t*t;
if (rsq<cf.x) {
*packed=j;
packed+=nbor_pitch;
newj++;
}
}
}
dev_nbor[ii+nbor_pitch]=newj;
}
}
// ---------------------------------------------------------------------------
// Unpack neighbors from dev_ij array into dev_nbor matrix for coalesced access
// -- Only unpack neighbors matching the specified inclusive range of forms
// -- Only unpack neighbors within cutoff
// -- Fast version of routine that uses shared memory for LJ constants
// ---------------------------------------------------------------------------
__kernel void kernel_gb_nbor_fast(__global numtyp4 *x_,
__global numtyp2 *cut_form,
__global int *dev_nbor,
const int nbor_pitch,
const int start, const int inum,
__global int *dev_ij, const int form_low,
const int form_high, const int nall) {
int ii=THREAD_ID_X;
__local int form[MAX_SHARED_TYPES*MAX_SHARED_TYPES];
__local numtyp cutsq[MAX_SHARED_TYPES*MAX_SHARED_TYPES];
if (ii<MAX_SHARED_TYPES*MAX_SHARED_TYPES) {
cutsq[ii]=cut_form[ii].x;
form[ii]=cut_form[ii].y;
}
ii+=mul24((int)BLOCK_SIZE_X,(int)BLOCK_ID_X)+start;
__syncthreads();
if (ii<inum) {
__global int *nbor=dev_ij+ii;
int i=*nbor;
nbor+=nbor_pitch;
int numj=*nbor;
nbor+=nbor_pitch;
__global int *list_end=nbor+mul24(numj,nbor_pitch);
__global int *packed=dev_nbor+ii+nbor_pitch+nbor_pitch;
numtyp4 ix=x_[i];
int iw=ix.w;
int itype=mul24((int)MAX_SHARED_TYPES,iw);
int newj=0;
for ( ; nbor<list_end; nbor+=nbor_pitch) {
int j=*nbor;
if (j>=nall)
j%=nall;
numtyp4 jx=x_[j];
int jtype=jx.w;
int mtype=itype+jtype;
if (form[mtype]>=form_low && form[mtype]<=form_high) {
// Compute r12;
numtyp rsq=jx.x-ix.x;
rsq*=rsq;
numtyp t=jx.y-ix.y;
rsq+=t*t;
t=jx.z-ix.z;
rsq+=t*t;
if (rsq<cutsq[mtype]) {
*packed=j;
packed+=nbor_pitch;
newj++;
}
}
}
dev_nbor[ii+nbor_pitch]=newj;
}
}
#endif

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