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lammps/lib/cuda/pair_lj_charmm_coul_charmm_implicit_cuda_kernel_nc.cu
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pair_lj_charmm_coul_charmm_implicit_cuda_kernel_nc.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.
------------------------------------------------------------------------- */
__device__ inline F_FLOAT CoulCharmmImplicitCuda_Eval(const F_FLOAT &rsq, F_FLOAT &factor_coul, int &eflag, ENERGY_FLOAT &ecoul, F_FLOAT qij)
{
F_FLOAT forcecoul;
ENERGY_FLOAT ecoul_tmp = forcecoul = _qqrd2e * qij * (F_F(1.0) / rsq) * factor_coul;
if(rsq > _cut_coul_innersq_global) {
const F_FLOAT switch1 = (_cut_coulsq_global - rsq) * (_cut_coulsq_global - rsq) *
(_cut_coulsq_global + F_F(2.0) * rsq - F_F(3.0) * _cut_coul_innersq_global) * _denom_coul_inv;
ecoul_tmp *= switch1;
const F_FLOAT switch2 = F_F(12.0) * rsq * (_cut_coulsq_global - rsq) *
(rsq - _cut_coul_innersq_global) * _denom_coul_inv;
forcecoul *= (switch1 + switch2);
}
if(eflag) {
ecoul += ecoul_tmp * factor_coul;
}
return F_F(2.0) * forcecoul * (F_F(1.0) / rsq);
}
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