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lammps/lib/cuda/fix_addforce_cuda_kernel.cu
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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;
}
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