lammps/lib/cuda/fix_addforce_cuda_kernel.cu

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/* ----------------------------------------------------------------------
LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
Original Version:
http://lammps.sandia.gov, Sandia National Laboratories
Steve Plimpton, sjplimp@sandia.gov
See the README file in the top-level LAMMPS directory.
-----------------------------------------------------------------------
USER-CUDA Package and associated modifications:
https://sourceforge.net/projects/lammpscuda/
Christian Trott, christian.trott@tu-ilmenau.de
Lars Winterfeld, lars.winterfeld@tu-ilmenau.de
Theoretical Physics II, University of Technology Ilmenau, Germany
See the README file in the USER-CUDA directory.
This software is distributed under the GNU General Public License.
------------------------------------------------------------------------- */
extern __shared__ F_FLOAT sharedmem[];
__global__ void Cuda_FixAddForceCuda_PostForce_Kernel(int groupbit,F_FLOAT xvalue,F_FLOAT yvalue,F_FLOAT zvalue)
{
int i=(blockIdx.x*gridDim.y+blockIdx.y)*blockDim.x+threadIdx.x;
sharedmem[threadIdx.x]=0;
sharedmem[threadIdx.x+blockDim.x]=0;
sharedmem[threadIdx.x+2*blockDim.x]=0;
sharedmem[threadIdx.x+3*blockDim.x]=0;
if(i < _nlocal)
if (_mask[i] & groupbit)
//if (iregion >= 0 &&
//match(x[i][0],x[i][1],x[i][2],iregion)) //currently not supported
{
sharedmem[threadIdx.x]=-xvalue*_x[i] - yvalue*_x[i+1*_nmax] - zvalue*_x[i+2*_nmax];
sharedmem[threadIdx.x+blockDim.x]=_f[i];
sharedmem[threadIdx.x+2*blockDim.x]=_f[i+1*_nmax];
sharedmem[threadIdx.x+3*blockDim.x]=_f[i+2*_nmax];
_f[i] += xvalue;
_f[i+1*_nmax] += yvalue;
_f[i+2*_nmax] += zvalue;
}
reduceBlock(sharedmem);
reduceBlock(&sharedmem[blockDim.x]);
reduceBlock(&sharedmem[2*blockDim.x]);
reduceBlock(&sharedmem[3*blockDim.x]);
F_FLOAT* buffer=(F_FLOAT*) _buffer;
if(threadIdx.x==0)
{
buffer[blockIdx.x*gridDim.y+blockIdx.y]=sharedmem[0];
buffer[blockIdx.x*gridDim.y+blockIdx.y+gridDim.x*gridDim.y]=sharedmem[blockDim.x];
buffer[blockIdx.x*gridDim.y+blockIdx.y+2*gridDim.x*gridDim.y]=sharedmem[2*blockDim.x];
buffer[blockIdx.x*gridDim.y+blockIdx.y+3*gridDim.x*gridDim.y]=sharedmem[3*blockDim.x];
}
}
__global__ void reduce_foriginal(int n,F_FLOAT* foriginal)
{
int i=0;
sharedmem[threadIdx.x]=0;
F_FLOAT myforig=0.0;
F_FLOAT* buf=(F_FLOAT*) _buffer;
buf=&buf[blockIdx.x*n];
while(i<n)
{
sharedmem[threadIdx.x]=0;
if(i+threadIdx.x<n)
sharedmem[threadIdx.x]=buf[i+threadIdx.x];
__syncthreads();
reduceBlock(sharedmem);
i+=blockDim.x;
if(threadIdx.x==0)
myforig+=sharedmem[0];
}
if(threadIdx.x==0)
foriginal[blockIdx.x]=myforig;
}