2 * This file is part of the GROMACS molecular simulation package.
4 * Copyright (c) 1991-2000, University of Groningen, The Netherlands.
5 * Copyright (c) 2001-2004, The GROMACS development team.
6 * Copyright (c) 2013,2014,2015,2016,2018,2019, by the GROMACS development team, led by
7 * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
8 * and including many others, as listed in the AUTHORS file in the
9 * top-level source directory and at http://www.gromacs.org.
11 * GROMACS is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU Lesser General Public License
13 * as published by the Free Software Foundation; either version 2.1
14 * of the License, or (at your option) any later version.
16 * GROMACS is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * Lesser General Public License for more details.
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with GROMACS; if not, see
23 * http://www.gnu.org/licenses, or write to the Free Software Foundation,
24 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
26 * If you want to redistribute modifications to GROMACS, please
27 * consider that scientific software is very special. Version
28 * control is crucial - bugs must be traceable. We will be happy to
29 * consider code for inclusion in the official distribution, but
30 * derived work must not be called official GROMACS. Details are found
31 * in the README & COPYING files - if they are missing, get the
32 * official version at http://www.gromacs.org.
34 * To help us fund GROMACS development, we humbly ask that you cite
35 * the research papers on the package. Check out http://www.gromacs.org.
37 /* This file is completely threadsafe - keep it that way! */
42 #include "config.h" /* for GMX_MAX_OPENMP_THREADS */
46 #include "gromacs/math/vec.h"
47 #include "gromacs/math/vectypes.h"
48 #include "gromacs/mdlib/gmx_omp_nthreads.h"
49 #include "gromacs/pbcutil/ishift.h"
50 #include "gromacs/pbcutil/mshift.h"
51 #include "gromacs/pbcutil/pbc.h"
52 #include "gromacs/utility/gmxassert.h"
64 static void upd_vir(rvec vir, real dvx, real dvy, real dvz)
71 static void calc_x_times_f(int nxf, const rvec x[], const rvec f[], gmx_bool bScrewPBC, const matrix box, matrix x_times_f)
75 for (int i = 0; i < nxf; i++)
77 for (int d = 0; d < DIM; d++)
79 for (int n = 0; n < DIM; n++)
81 x_times_f[d][n] += x[i][d] * f[i][n];
88 /* We should correct all odd x-shifts, but the range of isx is -2 to 2 */
89 if (isx == 1 || isx == -1)
91 for (int d = 0; d < DIM; d++)
93 for (int n = 0; n < DIM; n++)
95 x_times_f[d][n] += box[d][d] * f[i][n];
103 void calc_vir(int nxf, const rvec x[], const rvec f[], tensor vir, bool bScrewPBC, const matrix box)
107 int nthreads = gmx_omp_nthreads_get_simple_rvec_task(emntDefault, nxf * 9);
109 GMX_ASSERT(nthreads >= 1, "Avoids uninitialized x_times_f (warning)");
113 calc_x_times_f(nxf, x, f, bScrewPBC, box, x_times_f);
117 /* Use a buffer on the stack for storing thread-local results.
118 * We use 2 extra elements (=18 reals) per thread to separate thread
119 * local data by at least a cache line. Element 0 is not used.
121 matrix xf_buf[GMX_OPENMP_MAX_THREADS * 3];
123 #pragma omp parallel for num_threads(nthreads) schedule(static)
124 for (int thread = 0; thread < nthreads; thread++)
126 int start = (nxf * thread) / nthreads;
127 int end = std::min(nxf * (thread + 1) / nthreads, nxf);
129 calc_x_times_f(end - start, x + start, f + start, bScrewPBC, box,
130 thread == 0 ? x_times_f : xf_buf[thread * 3]);
133 for (int thread = 1; thread < nthreads; thread++)
135 m_add(x_times_f, xf_buf[thread * 3], x_times_f);
139 for (int d = 0; d < DIM; d++)
141 upd_vir(vir[d], x_times_f[d][XX], x_times_f[d][YY], x_times_f[d][ZZ]);
147 lo_fcv(int i0, int i1, const real x[], const real f[], tensor vir, const int is[], const real box[], gmx_bool bTriclinic)
149 int i, i3, tx, ty, tz;
151 real dvxx = 0, dvxy = 0, dvxz = 0, dvyx = 0, dvyy = 0, dvyz = 0, dvzx = 0, dvzy = 0, dvzz = 0;
155 for (i = i0; (i < i1); i++)
162 xx = x[i3 + XX] - tx * box[XXXX] - ty * box[YYXX] - tz * box[ZZXX];
163 dvxx += xx * f[i3 + XX];
164 dvxy += xx * f[i3 + YY];
165 dvxz += xx * f[i3 + ZZ];
167 yy = x[i3 + YY] - ty * box[YYYY] - tz * box[ZZYY];
168 dvyx += yy * f[i3 + XX];
169 dvyy += yy * f[i3 + YY];
170 dvyz += yy * f[i3 + ZZ];
172 zz = x[i3 + ZZ] - tz * box[ZZZZ];
173 dvzx += zz * f[i3 + XX];
174 dvzy += zz * f[i3 + YY];
175 dvzz += zz * f[i3 + ZZ];
180 for (i = i0; (i < i1); i++)
187 xx = x[i3 + XX] - tx * box[XXXX];
188 dvxx += xx * f[i3 + XX];
189 dvxy += xx * f[i3 + YY];
190 dvxz += xx * f[i3 + ZZ];
192 yy = x[i3 + YY] - ty * box[YYYY];
193 dvyx += yy * f[i3 + XX];
194 dvyy += yy * f[i3 + YY];
195 dvyz += yy * f[i3 + ZZ];
197 zz = x[i3 + ZZ] - tz * box[ZZZZ];
198 dvzx += zz * f[i3 + XX];
199 dvzy += zz * f[i3 + YY];
200 dvzz += zz * f[i3 + ZZ];
204 upd_vir(vir[XX], dvxx, dvxy, dvxz);
205 upd_vir(vir[YY], dvyx, dvyy, dvyz);
206 upd_vir(vir[ZZ], dvzx, dvzy, dvzz);
209 void f_calc_vir(int i0, int i1, const rvec x[], const rvec f[], tensor vir, const t_graph* g, const matrix box)
213 if (g && (g->nnodes > 0))
215 /* Calculate virial for bonded forces only when they belong to
218 start = std::max(i0, g->at_start);
219 end = std::min(i1, g->at_end);
220 lo_fcv(start, end, x[0], f[0], vir, g->ishift[0], box[0], TRICLINIC(box));
222 /* If not all atoms are bonded, calculate their virial contribution
223 * anyway, without shifting back their coordinates.
224 * Note the nifty pointer arithmetic...
228 calc_vir(start - i0, x + i0, f + i0, vir, FALSE, box);
232 calc_vir(i1 - end, x + end, f + end, vir, FALSE, box);
237 calc_vir(i1 - i0, x + i0, f + i0, vir, FALSE, box);