forked from lijiext/lammps
62 lines
2.1 KiB
Plaintext
62 lines
2.1 KiB
Plaintext
/* ----------------------------------------------------------------------
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LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
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Original Version:
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http://lammps.sandia.gov, Sandia National Laboratories
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Steve Plimpton, sjplimp@sandia.gov
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See the README file in the top-level LAMMPS directory.
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-----------------------------------------------------------------------
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USER-CUDA Package and associated modifications:
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https://sourceforge.net/projects/lammpscuda/
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Christian Trott, christian.trott@tu-ilmenau.de
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Lars Winterfeld, lars.winterfeld@tu-ilmenau.de
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Theoretical Physics II, University of Technology Ilmenau, Germany
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See the README file in the USER-CUDA directory.
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This software is distributed under the GNU General Public License.
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------------------------------------------------------------------------- */
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__device__ inline F_FLOAT PairLJSmoothCuda_Eval(const F_FLOAT &rsq, const int ij_type, F_FLOAT &factor_lj, int &eflag, ENERGY_FLOAT &evdwl)
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{
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F_FLOAT fskin, t, tsq, forcelj;
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const F_FLOAT r2inv = F_F(1.0) / rsq;
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const F_FLOAT r = _RSQRT_(r2inv);
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const F_FLOAT r6inv = r2inv * r2inv * r2inv;
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X_FLOAT cut_lj_innersq = (_cut_innersq_global > X_F(0.0) ? _cut_innersq_global : _cut_innersq[ij_type]);
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if(rsq < cut_lj_innersq) {
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forcelj = r6inv * (_lj1[ij_type] * r6inv - _lj2[ij_type]);
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} else {
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t = r - _SQRT_(cut_lj_innersq);
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tsq = t * t;
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fskin = _ljsw1[ij_type] + _ljsw2[ij_type] * t +
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_ljsw3[ij_type] * tsq + _ljsw4[ij_type] * tsq * t;
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forcelj = fskin * r;
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}
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if(eflag) {
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ENERGY_FLOAT evdwl_tmp;
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if(rsq < cut_lj_innersq) {
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evdwl_tmp = r6inv * (_lj3[ij_type] * r6inv - _lj4[ij_type]) -
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_offset[ij_type];
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} else {
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evdwl_tmp = _ljsw0[ij_type] - _ljsw1[ij_type] * t -
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_ljsw2[ij_type] * tsq * F_F(0.5) - _ljsw3[ij_type] * tsq * t * (F_F(1.0) / F_F(3.0)) -
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_ljsw4[ij_type] * tsq * tsq * (F_F(1.0) / F_F(4.0)) - _offset[ij_type];
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}
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evdwl += evdwl_tmp * factor_lj;
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}
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return factor_lj * forcelj * r2inv;
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}
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