lammps/lib/cuda/pair_lj_gromacs_cuda_kernel...

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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.
------------------------------------------------------------------------- */
__device__ inline F_FLOAT PairLJGromacsCuda_Eval(const F_FLOAT& rsq,const int ij_type,F_FLOAT& factor_lj,int& eflag, ENERGY_FLOAT& evdwl)
{
F_FLOAT tlj;
const F_FLOAT r2inv = F_F(1.0)/rsq;
const F_FLOAT r = _RSQRT_(r2inv);
const F_FLOAT r6inv = r2inv*r2inv*r2inv;
F_FLOAT forcelj = r6inv * (_lj1[ij_type]*r6inv - _lj2[ij_type]);
const X_FLOAT cut_lj_innersq=(_cut_innersq_global > X_F(0.0)? _cut_innersq_global : _cut_innersq[ij_type]);
if (rsq > cut_lj_innersq)
{
tlj = r - _SQRT_(cut_lj_innersq);
forcelj += r*tlj*tlj*(_ljsw1[ij_type] + _ljsw2[ij_type]*tlj);
}
if (eflag)
{
ENERGY_FLOAT evdwl_tmp = r6inv*(_lj3[ij_type]*r6inv-_lj4[ij_type]);
if (rsq > cut_lj_innersq)
{
evdwl_tmp += tlj*tlj*tlj*
(_ljsw3[ij_type] + _ljsw4[ij_type]*tlj) + _ljsw5[ij_type];;
}
evdwl+=evdwl_tmp*factor_lj;
}
return factor_lj*forcelj*r2inv;
}