lammps/lib/cuda/pair_lj_expand_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 PairLJExpandCuda_Eval(const F_FLOAT &rsq, const int ij_type, F_FLOAT &factor_lj, int &eflag, ENERGY_FLOAT &evdwl)
{
const F_FLOAT r = _SQRT_(rsq);
const F_FLOAT rshift = r - _shift[ij_type];
const F_FLOAT rshiftsq = rshift * rshift;
const F_FLOAT r2inv = F_F(1.0) / rshiftsq;
const F_FLOAT r6inv = r2inv * r2inv * r2inv;
const F_FLOAT forcelj = r6inv * (_lj1[ij_type] * r6inv - _lj2[ij_type]);
if(eflag) evdwl += factor_lj * (r6inv * (_lj3[ij_type] * r6inv - _lj4[ij_type]) - _offset[ij_type]);
return factor_lj * forcelj * (F_F(1.0) / rshift) * (F_F(1.0) / r);
}