1 // clang-format off
2 /* ----------------------------------------------------------------------
3 LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
4 https://www.lammps.org/, Sandia National Laboratories
5 Steve Plimpton, sjplimp@sandia.gov
6
7 Copyright (2003) Sandia Corporation. Under the terms of Contract
8 DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
9 certain rights in this software. This software is distributed under
10 the GNU General Public License.
11
12 See the README file in the top-level LAMMPS directory.
13 ------------------------------------------------------------------------- */
14
15 /* ----------------------------------------------------------------------
16 Contributing author: Axel Kohlmeyer (Temple U)
17 ------------------------------------------------------------------------- */
18
19 #include "omp_compat.h"
20 #include "angle_cosine_delta_omp.h"
21 #include <cmath>
22 #include "atom.h"
23 #include "comm.h"
24 #include "force.h"
25 #include "neighbor.h"
26
27
28 #include "suffix.h"
29 using namespace LAMMPS_NS;
30
31 #define SMALL 0.001
32
33 /* ---------------------------------------------------------------------- */
34
AngleCosineDeltaOMP(class LAMMPS * lmp)35 AngleCosineDeltaOMP::AngleCosineDeltaOMP(class LAMMPS *lmp)
36 : AngleCosineDelta(lmp), ThrOMP(lmp,THR_ANGLE)
37 {
38 suffix_flag |= Suffix::OMP;
39 }
40
41 /* ---------------------------------------------------------------------- */
42
compute(int eflag,int vflag)43 void AngleCosineDeltaOMP::compute(int eflag, int vflag)
44 {
45 ev_init(eflag,vflag);
46
47 const int nall = atom->nlocal + atom->nghost;
48 const int nthreads = comm->nthreads;
49 const int inum = neighbor->nanglelist;
50
51 #if defined(_OPENMP)
52 #pragma omp parallel LMP_DEFAULT_NONE LMP_SHARED(eflag,vflag)
53 #endif
54 {
55 int ifrom, ito, tid;
56
57 loop_setup_thr(ifrom, ito, tid, inum, nthreads);
58 ThrData *thr = fix->get_thr(tid);
59 thr->timer(Timer::START);
60 ev_setup_thr(eflag, vflag, nall, eatom, vatom, cvatom, thr);
61
62 if (inum > 0) {
63 if (evflag) {
64 if (eflag) {
65 if (force->newton_bond) eval<1,1,1>(ifrom, ito, thr);
66 else eval<1,1,0>(ifrom, ito, thr);
67 } else {
68 if (force->newton_bond) eval<1,0,1>(ifrom, ito, thr);
69 else eval<1,0,0>(ifrom, ito, thr);
70 }
71 } else {
72 if (force->newton_bond) eval<0,0,1>(ifrom, ito, thr);
73 else eval<0,0,0>(ifrom, ito, thr);
74 }
75 }
76 thr->timer(Timer::BOND);
77 reduce_thr(this, eflag, vflag, thr);
78 } // end of omp parallel region
79 }
80
81 template <int EVFLAG, int EFLAG, int NEWTON_BOND>
eval(int nfrom,int nto,ThrData * const thr)82 void AngleCosineDeltaOMP::eval(int nfrom, int nto, ThrData * const thr)
83 {
84 int i1,i2,i3,n,type;
85 double delx1,dely1,delz1,delx2,dely2,delz2,theta,dtheta,dcostheta,tk;
86 double eangle,f1[3],f3[3];
87 double rsq1,rsq2,r1,r2,c,a,cot,a11,a12,a22,b11,b12,b22,c0,s0,s;
88
89 const dbl3_t * _noalias const x = (dbl3_t *) atom->x[0];
90 dbl3_t * _noalias const f = (dbl3_t *) thr->get_f()[0];
91 const int4_t * _noalias const anglelist = (int4_t *) neighbor->anglelist[0];
92 const int nlocal = atom->nlocal;
93 eangle = 0.0;
94
95 for (n = nfrom; n < nto; n++) {
96 i1 = anglelist[n].a;
97 i2 = anglelist[n].b;
98 i3 = anglelist[n].c;
99 type = anglelist[n].t;
100
101 // 1st bond
102
103 delx1 = x[i1].x - x[i2].x;
104 dely1 = x[i1].y - x[i2].y;
105 delz1 = x[i1].z - x[i2].z;
106
107 rsq1 = delx1*delx1 + dely1*dely1 + delz1*delz1;
108 r1 = sqrt(rsq1);
109
110 // 2nd bond
111
112 delx2 = x[i3].x - x[i2].x;
113 dely2 = x[i3].y - x[i2].y;
114 delz2 = x[i3].z - x[i2].z;
115
116 rsq2 = delx2*delx2 + dely2*dely2 + delz2*delz2;
117 r2 = sqrt(rsq2);
118
119 // angle (cos and sin)
120
121 c = delx1*delx2 + dely1*dely2 + delz1*delz2;
122 c /= r1*r2;
123
124 if (c > 1.0) c = 1.0;
125 if (c < -1.0) c = -1.0;
126
127 theta = acos(c);
128
129 s = sqrt(1.0 - c*c);
130 if (s < SMALL) s = SMALL;
131 s = 1.0/s;
132
133 cot = c/s;
134
135 // force & energy
136
137 dtheta = theta - theta0[type];
138 dcostheta = cos(dtheta);
139 tk = k[type] * (1.0-dcostheta);
140
141 if (EFLAG) eangle = tk;
142
143 a = -k[type];
144
145 // expand dtheta for cos and sin contribution to force
146
147 a11 = a*c / rsq1;
148 a12 = -a / (r1*r2);
149 a22 = a*c / rsq2;
150
151 b11 = -a*c*cot / rsq1;
152 b12 = a*cot / (r1*r2);
153 b22 = -a*c*cot / rsq2;
154
155 c0 = cos(theta0[type]);
156 s0 = sin(theta0[type]);
157
158 f1[0] = (a11*delx1 + a12*delx2)*c0 + (b11*delx1 + b12*delx2)*s0;
159 f1[1] = (a11*dely1 + a12*dely2)*c0 + (b11*dely1 + b12*dely2)*s0;
160 f1[2] = (a11*delz1 + a12*delz2)*c0 + (b11*delz1 + b12*delz2)*s0;
161 f3[0] = (a22*delx2 + a12*delx1)*c0 + (b22*delx2 + b12*delx1)*s0;
162 f3[1] = (a22*dely2 + a12*dely1)*c0 + (b22*dely2 + b12*dely1)*s0;
163 f3[2] = (a22*delz2 + a12*delz1)*c0 + (b22*delz2 + b12*delz1)*s0;
164
165 // apply force to each of 3 atoms
166
167 if (NEWTON_BOND || i1 < nlocal) {
168 f[i1].x += f1[0];
169 f[i1].y += f1[1];
170 f[i1].z += f1[2];
171 }
172
173 if (NEWTON_BOND || i2 < nlocal) {
174 f[i2].x -= f1[0] + f3[0];
175 f[i2].y -= f1[1] + f3[1];
176 f[i2].z -= f1[2] + f3[2];
177 }
178
179 if (NEWTON_BOND || i3 < nlocal) {
180 f[i3].x += f3[0];
181 f[i3].y += f3[1];
182 f[i3].z += f3[2];
183 }
184
185 if (EVFLAG) ev_tally_thr(this,i1,i2,i3,nlocal,NEWTON_BOND,eangle,f1,f3,
186 delx1,dely1,delz1,delx2,dely2,delz2,thr);
187 }
188 }
189