/// The force exchange is considerably simpler than the atom exchange.
/// In the force case we only need to exchange data that is needed to
/// complete the force calculation. Since the atoms have not moved we
/// only need to send data from local link cells and we are guaranteed
/// that the same atoms exist in the same order in corresponding halo
/// cells on remote tasks. The only tricky part is the size of the
/// plane of local cells that needs to be sent grows in each direction.
/// This is because the y-axis send must send some of the data that was
/// received from the x-axis send, and the z-axis must send some data
/// from the y-axis send. This accumulation of data to send is
/// responsible for data reaching neighbor cells that share only edges
/// or corners.
///
/// \see eam.c for an explanation of the requirement to exchange
/// force data.
HaloExchange* initForceHaloExchange(Domain* domain, LinkCell* boxes)
{
HaloExchange* hh = initHaloExchange(domain);
hh->loadBuffer = loadForceBuffer;
hh->unloadBuffer = unloadForceBuffer;
hh->destroy = destroyForceExchange;
int size0 = (boxes->gridSize[1])*(boxes->gridSize[2]);
int size1 = (boxes->gridSize[0]+2)*(boxes->gridSize[2]);
int size2 = (boxes->gridSize[0]+2)*(boxes->gridSize[1]+2);
int maxSize = MAX(size0, size1);
maxSize = MAX(size1, size2);
hh->bufCapacity = (maxSize)*MAXATOMS*sizeof(ForceMsg);
ForceExchangeParms* parms = comdMalloc(sizeof(ForceExchangeParms));
parms->nCells[HALO_X_MINUS] = (boxes->gridSize[1] )*(boxes->gridSize[2] );
parms->nCells[HALO_Y_MINUS] = (boxes->gridSize[0]+2)*(boxes->gridSize[2] );
parms->nCells[HALO_Z_MINUS] = (boxes->gridSize[0]+2)*(boxes->gridSize[1]+2);
parms->nCells[HALO_X_PLUS] = parms->nCells[HALO_X_MINUS];
parms->nCells[HALO_Y_PLUS] = parms->nCells[HALO_Y_MINUS];
parms->nCells[HALO_Z_PLUS] = parms->nCells[HALO_Z_MINUS];
for (int ii=0; ii<6; ++ii)
{
parms->sendCells[ii] = mkForceSendCellList(boxes, ii, parms->nCells[ii]);
parms->recvCells[ii] = mkForceRecvCellList(boxes, ii, parms->nCells[ii]);
}
hh->parms = parms;
return hh;
}
/// The force exchange is considerably simpler than the atom exchange.
/// In the force case we only need to exchange data that is needed to
/// complete the force calculation. Since the atoms have not moved we
/// only need to send data from local link cells and we are guaranteed
/// that the same atoms exist in the same order in corresponding halo
/// cells on remote tasks. The only tricky part is the size of the
/// plane of local cells that needs to be sent grows in each direction.
/// This is because the y-axis send must send some of the data that was
/// received from the x-axis send, and the z-axis must send some data
/// from the y-axis send. This accumulation of data to send is
/// responsible for data reaching neighbor cells that share only edges
/// or corners.
///
/// \see eam.c for an explanation of the requirement to exchange
/// force data.
HaloExchange* initForceHaloExchange(Domain* domain, LinkCell* boxes, int useGPU)
{
HaloExchange* hh = initHaloExchange(domain);
if(useGPU){
hh->loadBuffer = loadForceBuffer;
hh->unloadBuffer = unloadForceBuffer;
}else{
hh->loadBuffer = loadForceBufferCpu;
hh->unloadBuffer = unloadForceBufferCpu;
}
hh->destroy = destroyForceExchange;
int size0 = (boxes->gridSize[1])*(boxes->gridSize[2]);
int size1 = (boxes->gridSize[0]+2)*(boxes->gridSize[2]);
int size2 = (boxes->gridSize[0]+2)*(boxes->gridSize[1]+2);
int maxSize = MAX(size0, size1);
maxSize = MAX(size1, size2);
hh->bufCapacity = (maxSize)*MAXATOMS*sizeof(ForceMsg);
hh->sendBufM = (char*)comdMalloc(hh->bufCapacity);
hh->sendBufP = (char*)comdMalloc(hh->bufCapacity);
hh->recvBufP = (char*)comdMalloc(hh->bufCapacity);
hh->recvBufM = (char*)comdMalloc(hh->bufCapacity);
// pin memory
cudaHostRegister(hh->sendBufM, hh->bufCapacity, 0);
cudaHostRegister(hh->sendBufP, hh->bufCapacity, 0);
cudaHostRegister(hh->recvBufP, hh->bufCapacity, 0);
cudaHostRegister(hh->recvBufM, hh->bufCapacity, 0);
ForceExchangeParms* parms = (ForceExchangeParms*)comdMalloc(sizeof(ForceExchangeParms));
parms->nCells[HALO_X_MINUS] = (boxes->gridSize[1] )*(boxes->gridSize[2] );
parms->nCells[HALO_Y_MINUS] = (boxes->gridSize[0]+2)*(boxes->gridSize[2] );
parms->nCells[HALO_Z_MINUS] = (boxes->gridSize[0]+2)*(boxes->gridSize[1]+2);
parms->nCells[HALO_X_PLUS] = parms->nCells[HALO_X_MINUS];
parms->nCells[HALO_Y_PLUS] = parms->nCells[HALO_Y_MINUS];
parms->nCells[HALO_Z_PLUS] = parms->nCells[HALO_Z_MINUS];
for (int ii=0; ii<6; ++ii)
{
parms->sendCells[ii] = mkForceSendCellList(boxes, ii, parms->nCells[ii]);
parms->recvCells[ii] = mkForceRecvCellList(boxes, ii, parms->nCells[ii]);
// copy cell list to gpu
cudaMalloc((void**)&parms->sendCellsGpu[ii], parms->nCells[ii] * sizeof(int));
cudaMalloc((void**)&parms->recvCellsGpu[ii], parms->nCells[ii] * sizeof(int));
cudaMemcpy(parms->sendCellsGpu[ii], parms->sendCells[ii], parms->nCells[ii] * sizeof(int), cudaMemcpyHostToDevice);
cudaMemcpy(parms->recvCellsGpu[ii], parms->recvCells[ii], parms->nCells[ii] * sizeof(int), cudaMemcpyHostToDevice);
// allocate temp buf
int size = parms->nCells[ii]+1;
if (size % 256 != 0) size = ((size + 255)/256)*256;
cudaMalloc((void**)&parms->natoms_buf[ii], size * sizeof(int));
cudaMalloc((void**)&parms->partial_sums[ii], (size/256 + 1) * sizeof(int));
}
hh->hashTable = NULL;
hh->type = 1;
hh->parms = parms;
return hh;
}