lammps/lib/gpu/pair_gpu_nbor.cu

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/***************************************************************************
pair_gpu_nbor.cu
-------------------
W. Michael Brown
Neighbor memory operations for LAMMPS GPU Library
__________________________________________________________________________
This file is part of the LAMMPS GPU Library
__________________________________________________________________________
begin : Tue Aug 4 2009
copyright : (C) 2009 by W. Michael Brown
email : wmbrown@sandia.gov
***************************************************************************/
/* -----------------------------------------------------------------------
Copyright (2009) 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.
----------------------------------------------------------------------- */
#include "pair_gpu_nbor.h"
int PairGPUNbor::bytes_per_atom(const int max_nbors) const {
if (_use_packing)
return (max_nbors*2+4)*sizeof(int);
else
return (max_nbors+3)*sizeof(int);
}
void PairGPUNbor::init(const int ij_size, const int max_atoms,
const int max_nbors) {
if (allocated)
clear();
// Initialize timers for the selected GPU
time_nbor.init();
if (_use_packing)
dev_nbor.safe_alloc(max_nbors+4,max_atoms);
else
dev_nbor.safe_alloc(3,max_atoms);
ij.safe_alloc(max_nbors*max_atoms);
host_ij.safe_alloc_w(ij_size);
allocated=true;
}
void PairGPUNbor::clear() {
if (!allocated)
return;
allocated=false;
ij.clear();
host_ij.clear();
dev_nbor.clear();
}
double PairGPUNbor::host_memory_usage() const {
return IJ_SIZE*sizeof(int)+sizeof(PairGPUNbor);
}
void PairGPUNbor::reset(const int inum, int *ilist, const int *numj,
cudaStream_t &s) {
ij_total=0;
dev_nbor.copy_from_host(ilist,inum);
int acc=0;
for (int i=0; i<inum; i++) {
host_ij[i]=numj[ilist[i]];
host_ij[i+inum]=acc;
acc+=numj[ilist[i]];
}
host_ij.copy_to_2Ddevice(dev_nbor.begin()+dev_nbor.row_size(),
dev_nbor.row_size(),2,inum, s);
}