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) 2011,2012,2013,2014, 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.
44 #include "gromacs/random/random.h"
45 #include "gromacs/utility/smalloc.h"
52 #include "gromacs/random/random.h"
54 #define PROBABILITYCUTOFF 100
55 /* we don't bother evaluating if events are more rare than exp(-100) = 3.7x10^-44 */
58 ereTEMP, ereLAMBDA, ereENDSINGLE, ereTL, ereNR
60 const char *erename[ereNR] = { "temperature", "lambda", "end_single_marker", "temperature and lambda"};
61 /* end_single_marker merely notes the end of single variable replica exchange. All types higher than
62 it are multiple replica exchange methods */
63 /* Eventually, should add 'pressure', 'temperature and pressure', 'lambda_and_pressure', 'temperature_lambda_pressure'?;
64 Let's wait until we feel better about the pressure control methods giving exact ensembles. Right now, we assume constant pressure */
66 typedef struct gmx_repl_ex
86 /* these are helper arrays for replica exchange; allocated here so they
87 don't have to be allocated each time */
95 /* helper arrays to hold the quantities that are exchanged */
104 static gmx_bool repl_quantity(const gmx_multisim_t *ms,
105 struct gmx_repl_ex *re, int ere, real q)
111 snew(qall, ms->nsim);
113 gmx_sum_sim(ms->nsim, qall, ms);
116 for (s = 1; s < ms->nsim; s++)
118 if (qall[s] != qall[0])
126 /* Set the replica exchange type and quantities */
129 snew(re->q[ere], re->nrepl);
130 for (s = 0; s < ms->nsim; s++)
132 re->q[ere][s] = qall[s];
139 gmx_repl_ex_t init_replica_exchange(FILE *fplog,
140 const gmx_multisim_t *ms,
141 const t_state *state,
142 const t_inputrec *ir,
143 int nst, int nex, int init_seed)
147 struct gmx_repl_ex *re;
149 gmx_bool bLambda = FALSE;
151 fprintf(fplog, "\nInitializing Replica Exchange\n");
153 if (ms == NULL || ms->nsim == 1)
155 gmx_fatal(FARGS, "Nothing to exchange with only one replica, maybe you forgot to set the -multi option of mdrun?");
157 if (!EI_DYNAMICS(ir->eI))
159 gmx_fatal(FARGS, "Replica exchange is only supported by dynamical simulations");
160 /* Note that PAR(cr) is defined by cr->nnodes > 1, which is
161 * distinct from MULTISIM(cr). A multi-simulation only runs
162 * with real MPI parallelism, but this does not imply PAR(cr)
165 * Since we are using a dynamical integrator, the only
166 * decomposition is DD, so PAR(cr) and DOMAINDECOMP(cr) are
167 * synonymous. The only way for cr->nnodes > 1 to be true is
168 * if we are using DD. */
174 re->nrepl = ms->nsim;
175 snew(re->q, ereENDSINGLE);
177 fprintf(fplog, "Repl There are %d replicas:\n", re->nrepl);
179 check_multi_int(fplog, ms, state->natoms, "the number of atoms", FALSE);
180 check_multi_int(fplog, ms, ir->eI, "the integrator", FALSE);
181 check_multi_int64(fplog, ms, ir->init_step+ir->nsteps, "init_step+nsteps", FALSE);
182 check_multi_int64(fplog, ms, (ir->init_step+nst-1)/nst,
183 "first exchange step: init_step/-replex", FALSE);
184 check_multi_int(fplog, ms, ir->etc, "the temperature coupling", FALSE);
185 check_multi_int(fplog, ms, ir->opts.ngtc,
186 "the number of temperature coupling groups", FALSE);
187 check_multi_int(fplog, ms, ir->epc, "the pressure coupling", FALSE);
188 check_multi_int(fplog, ms, ir->efep, "free energy", FALSE);
189 check_multi_int(fplog, ms, ir->fepvals->n_lambda, "number of lambda states", FALSE);
191 re->temp = ir->opts.ref_t[0];
192 for (i = 1; (i < ir->opts.ngtc); i++)
194 if (ir->opts.ref_t[i] != re->temp)
196 fprintf(fplog, "\nWARNING: The temperatures of the different temperature coupling groups are not identical\n\n");
197 fprintf(stderr, "\nWARNING: The temperatures of the different temperature coupling groups are not identical\n\n");
202 bTemp = repl_quantity(ms, re, ereTEMP, re->temp);
203 if (ir->efep != efepNO)
205 bLambda = repl_quantity(ms, re, ereLAMBDA, (real)ir->fepvals->init_fep_state);
207 if (re->type == -1) /* nothing was assigned */
209 gmx_fatal(FARGS, "The properties of the %d systems are all the same, there is nothing to exchange", re->nrepl);
211 if (bLambda && bTemp)
218 please_cite(fplog, "Sugita1999a");
219 if (ir->epc != epcNO)
222 fprintf(fplog, "Repl Using Constant Pressure REMD.\n");
223 please_cite(fplog, "Okabe2001a");
225 if (ir->etc == etcBERENDSEN)
227 gmx_fatal(FARGS, "REMD with the %s thermostat does not produce correct potential energy distributions, consider using the %s thermostat instead",
228 ETCOUPLTYPE(ir->etc), ETCOUPLTYPE(etcVRESCALE));
233 if (ir->fepvals->delta_lambda != 0) /* check this? */
235 gmx_fatal(FARGS, "delta_lambda is not zero");
240 snew(re->pres, re->nrepl);
241 if (ir->epct == epctSURFACETENSION)
243 pres = ir->ref_p[ZZ][ZZ];
249 for (i = 0; i < DIM; i++)
251 if (ir->compress[i][i] != 0)
253 pres += ir->ref_p[i][i];
259 re->pres[re->repl] = pres;
260 gmx_sum_sim(re->nrepl, re->pres, ms);
263 /* Make an index for increasing replica order */
264 /* only makes sense if one or the other is varying, not both!
265 if both are varying, we trust the order the person gave. */
266 snew(re->ind, re->nrepl);
267 for (i = 0; i < re->nrepl; i++)
272 if (re->type < ereENDSINGLE)
275 for (i = 0; i < re->nrepl; i++)
277 for (j = i+1; j < re->nrepl; j++)
279 if (re->q[re->type][re->ind[j]] < re->q[re->type][re->ind[i]])
282 re->ind[i] = re->ind[j];
285 else if (re->q[re->type][re->ind[j]] == re->q[re->type][re->ind[i]])
287 gmx_fatal(FARGS, "Two replicas have identical %ss", erename[re->type]);
293 /* keep track of all the swaps, starting with the initial placement. */
294 snew(re->allswaps, re->nrepl);
295 for (i = 0; i < re->nrepl; i++)
297 re->allswaps[i] = re->ind[i];
303 fprintf(fplog, "\nReplica exchange in temperature\n");
304 for (i = 0; i < re->nrepl; i++)
306 fprintf(fplog, " %5.1f", re->q[re->type][re->ind[i]]);
308 fprintf(fplog, "\n");
311 fprintf(fplog, "\nReplica exchange in lambda\n");
312 for (i = 0; i < re->nrepl; i++)
314 fprintf(fplog, " %3d", (int)re->q[re->type][re->ind[i]]);
316 fprintf(fplog, "\n");
319 fprintf(fplog, "\nReplica exchange in temperature and lambda state\n");
320 for (i = 0; i < re->nrepl; i++)
322 fprintf(fplog, " %5.1f", re->q[ereTEMP][re->ind[i]]);
324 fprintf(fplog, "\n");
325 for (i = 0; i < re->nrepl; i++)
327 fprintf(fplog, " %5d", (int)re->q[ereLAMBDA][re->ind[i]]);
329 fprintf(fplog, "\n");
332 gmx_incons("Unknown replica exchange quantity");
336 fprintf(fplog, "\nRepl p");
337 for (i = 0; i < re->nrepl; i++)
339 fprintf(fplog, " %5.2f", re->pres[re->ind[i]]);
342 for (i = 0; i < re->nrepl; i++)
344 if ((i > 0) && (re->pres[re->ind[i]] < re->pres[re->ind[i-1]]))
346 fprintf(fplog, "\nWARNING: The reference pressures decrease with increasing temperatures\n\n");
347 fprintf(stderr, "\nWARNING: The reference pressures decrease with increasing temperatures\n\n");
356 re->seed = (int)gmx_rng_make_seed();
362 gmx_sumi_sim(1, &(re->seed), ms);
366 re->seed = init_seed;
368 fprintf(fplog, "\nReplica exchange interval: %d\n", re->nst);
369 fprintf(fplog, "\nReplica random seed: %d\n", re->seed);
370 re->rng = gmx_rng_init(re->seed);
375 snew(re->prob_sum, re->nrepl);
376 snew(re->nexchange, re->nrepl);
377 snew(re->nmoves, re->nrepl);
378 for (i = 0; i < re->nrepl; i++)
380 snew(re->nmoves[i], re->nrepl);
382 fprintf(fplog, "Replica exchange information below: x=exchange, pr=probability\n");
384 /* generate space for the helper functions so we don't have to snew each time */
386 snew(re->destinations, re->nrepl);
387 snew(re->incycle, re->nrepl);
388 snew(re->tmpswap, re->nrepl);
389 snew(re->cyclic, re->nrepl);
390 snew(re->order, re->nrepl);
391 for (i = 0; i < re->nrepl; i++)
393 snew(re->cyclic[i], re->nrepl);
394 snew(re->order[i], re->nrepl);
396 /* allocate space for the functions storing the data for the replicas */
397 /* not all of these arrays needed in all cases, but they don't take
398 up much space, since the max size is nrepl**2 */
399 snew(re->prob, re->nrepl);
400 snew(re->bEx, re->nrepl);
401 snew(re->beta, re->nrepl);
402 snew(re->Vol, re->nrepl);
403 snew(re->Epot, re->nrepl);
404 snew(re->de, re->nrepl);
405 for (i = 0; i < re->nrepl; i++)
407 snew(re->de[i], re->nrepl);
413 static void exchange_reals(const gmx_multisim_t gmx_unused *ms, int gmx_unused b, real *v, int n)
423 MPI_Sendrecv(v, n*sizeof(real),MPI_BYTE,MSRANK(ms,b),0,
424 buf,n*sizeof(real),MPI_BYTE,MSRANK(ms,b),0,
425 ms->mpi_comm_masters,MPI_STATUS_IGNORE);
430 MPI_Isend(v, n*sizeof(real), MPI_BYTE, MSRANK(ms, b), 0,
431 ms->mpi_comm_masters, &mpi_req);
432 MPI_Recv(buf, n*sizeof(real), MPI_BYTE, MSRANK(ms, b), 0,
433 ms->mpi_comm_masters, MPI_STATUS_IGNORE);
434 MPI_Wait(&mpi_req, MPI_STATUS_IGNORE);
437 for (i = 0; i < n; i++)
446 static void exchange_ints(const gmx_multisim_t gmx_unused *ms, int gmx_unused b, int *v, int n)
456 MPI_Sendrecv(v, n*sizeof(int),MPI_BYTE,MSRANK(ms,b),0,
457 buf,n*sizeof(int),MPI_BYTE,MSRANK(ms,b),0,
458 ms->mpi_comm_masters,MPI_STATUS_IGNORE);
463 MPI_Isend(v, n*sizeof(int), MPI_BYTE, MSRANK(ms, b), 0,
464 ms->mpi_comm_masters, &mpi_req);
465 MPI_Recv(buf, n*sizeof(int), MPI_BYTE, MSRANK(ms, b), 0,
466 ms->mpi_comm_masters, MPI_STATUS_IGNORE);
467 MPI_Wait(&mpi_req, MPI_STATUS_IGNORE);
470 for (i = 0; i < n; i++)
478 static void exchange_doubles(const gmx_multisim_t gmx_unused *ms, int gmx_unused b, double *v, int n)
488 MPI_Sendrecv(v, n*sizeof(double),MPI_BYTE,MSRANK(ms,b),0,
489 buf,n*sizeof(double),MPI_BYTE,MSRANK(ms,b),0,
490 ms->mpi_comm_masters,MPI_STATUS_IGNORE);
495 MPI_Isend(v, n*sizeof(double), MPI_BYTE, MSRANK(ms, b), 0,
496 ms->mpi_comm_masters, &mpi_req);
497 MPI_Recv(buf, n*sizeof(double), MPI_BYTE, MSRANK(ms, b), 0,
498 ms->mpi_comm_masters, MPI_STATUS_IGNORE);
499 MPI_Wait(&mpi_req, MPI_STATUS_IGNORE);
502 for (i = 0; i < n; i++)
510 static void exchange_rvecs(const gmx_multisim_t gmx_unused *ms, int gmx_unused b, rvec *v, int n)
520 MPI_Sendrecv(v[0], n*sizeof(rvec),MPI_BYTE,MSRANK(ms,b),0,
521 buf[0],n*sizeof(rvec),MPI_BYTE,MSRANK(ms,b),0,
522 ms->mpi_comm_masters,MPI_STATUS_IGNORE);
527 MPI_Isend(v[0], n*sizeof(rvec), MPI_BYTE, MSRANK(ms, b), 0,
528 ms->mpi_comm_masters, &mpi_req);
529 MPI_Recv(buf[0], n*sizeof(rvec), MPI_BYTE, MSRANK(ms, b), 0,
530 ms->mpi_comm_masters, MPI_STATUS_IGNORE);
531 MPI_Wait(&mpi_req, MPI_STATUS_IGNORE);
534 for (i = 0; i < n; i++)
536 copy_rvec(buf[i], v[i]);
542 static void exchange_state(const gmx_multisim_t *ms, int b, t_state *state)
544 /* When t_state changes, this code should be updated. */
546 ngtc = state->ngtc * state->nhchainlength;
547 nnhpres = state->nnhpres* state->nhchainlength;
548 exchange_rvecs(ms, b, state->box, DIM);
549 exchange_rvecs(ms, b, state->box_rel, DIM);
550 exchange_rvecs(ms, b, state->boxv, DIM);
551 exchange_reals(ms, b, &(state->veta), 1);
552 exchange_reals(ms, b, &(state->vol0), 1);
553 exchange_rvecs(ms, b, state->svir_prev, DIM);
554 exchange_rvecs(ms, b, state->fvir_prev, DIM);
555 exchange_rvecs(ms, b, state->pres_prev, DIM);
556 exchange_doubles(ms, b, state->nosehoover_xi, ngtc);
557 exchange_doubles(ms, b, state->nosehoover_vxi, ngtc);
558 exchange_doubles(ms, b, state->nhpres_xi, nnhpres);
559 exchange_doubles(ms, b, state->nhpres_vxi, nnhpres);
560 exchange_doubles(ms, b, state->therm_integral, state->ngtc);
561 exchange_rvecs(ms, b, state->x, state->natoms);
562 exchange_rvecs(ms, b, state->v, state->natoms);
563 exchange_rvecs(ms, b, state->sd_X, state->natoms);
566 static void copy_rvecs(rvec *s, rvec *d, int n)
572 for (i = 0; i < n; i++)
574 copy_rvec(s[i], d[i]);
579 static void copy_doubles(const double *s, double *d, int n)
585 for (i = 0; i < n; i++)
592 static void copy_reals(const real *s, real *d, int n)
598 for (i = 0; i < n; i++)
605 static void copy_ints(const int *s, int *d, int n)
611 for (i = 0; i < n; i++)
618 #define scopy_rvecs(v, n) copy_rvecs(state->v, state_local->v, n);
619 #define scopy_doubles(v, n) copy_doubles(state->v, state_local->v, n);
620 #define scopy_reals(v, n) copy_reals(state->v, state_local->v, n);
621 #define scopy_ints(v, n) copy_ints(state->v, state_local->v, n);
623 static void copy_state_nonatomdata(t_state *state, t_state *state_local)
625 /* When t_state changes, this code should be updated. */
627 ngtc = state->ngtc * state->nhchainlength;
628 nnhpres = state->nnhpres* state->nhchainlength;
629 scopy_rvecs(box, DIM);
630 scopy_rvecs(box_rel, DIM);
631 scopy_rvecs(boxv, DIM);
632 state_local->veta = state->veta;
633 state_local->vol0 = state->vol0;
634 scopy_rvecs(svir_prev, DIM);
635 scopy_rvecs(fvir_prev, DIM);
636 scopy_rvecs(pres_prev, DIM);
637 scopy_doubles(nosehoover_xi, ngtc);
638 scopy_doubles(nosehoover_vxi, ngtc);
639 scopy_doubles(nhpres_xi, nnhpres);
640 scopy_doubles(nhpres_vxi, nnhpres);
641 scopy_doubles(therm_integral, state->ngtc);
642 scopy_rvecs(x, state->natoms);
643 scopy_rvecs(v, state->natoms);
644 scopy_rvecs(sd_X, state->natoms);
645 copy_ints(&(state->fep_state), &(state_local->fep_state), 1);
646 scopy_reals(lambda, efptNR);
649 static void scale_velocities(t_state *state, real fac)
655 for (i = 0; i < state->natoms; i++)
657 svmul(fac, state->v[i], state->v[i]);
662 static void print_transition_matrix(FILE *fplog, int n, int **nmoves, int *nattempt)
667 ntot = nattempt[0] + nattempt[1];
668 fprintf(fplog, "\n");
669 fprintf(fplog, "Repl");
670 for (i = 0; i < n; i++)
672 fprintf(fplog, " "); /* put the title closer to the center */
674 fprintf(fplog, "Empirical Transition Matrix\n");
676 fprintf(fplog, "Repl");
677 for (i = 0; i < n; i++)
679 fprintf(fplog, "%8d", (i+1));
681 fprintf(fplog, "\n");
683 for (i = 0; i < n; i++)
685 fprintf(fplog, "Repl");
686 for (j = 0; j < n; j++)
689 if (nmoves[i][j] > 0)
691 Tprint = nmoves[i][j]/(2.0*ntot);
693 fprintf(fplog, "%8.4f", Tprint);
695 fprintf(fplog, "%3d\n", i);
699 static void print_ind(FILE *fplog, const char *leg, int n, int *ind, gmx_bool *bEx)
703 fprintf(fplog, "Repl %2s %2d", leg, ind[0]);
704 for (i = 1; i < n; i++)
706 fprintf(fplog, " %c %2d", (bEx != 0 && bEx[i]) ? 'x' : ' ', ind[i]);
708 fprintf(fplog, "\n");
711 static void print_allswitchind(FILE *fplog, int n, int *pind, int *allswaps, int *tmpswap)
715 for (i = 0; i < n; i++)
717 tmpswap[i] = allswaps[i];
719 for (i = 0; i < n; i++)
721 allswaps[i] = tmpswap[pind[i]];
724 fprintf(fplog, "\nAccepted Exchanges: ");
725 for (i = 0; i < n; i++)
727 fprintf(fplog, "%d ", pind[i]);
729 fprintf(fplog, "\n");
731 /* the "Order After Exchange" is the state label corresponding to the configuration that
732 started in state listed in order, i.e.
737 configuration starting in simulation 3 is now in simulation 0,
738 configuration starting in simulation 0 is now in simulation 1,
739 configuration starting in simulation 1 is now in simulation 2,
740 configuration starting in simulation 2 is now in simulation 3
742 fprintf(fplog, "Order After Exchange: ");
743 for (i = 0; i < n; i++)
745 fprintf(fplog, "%d ", allswaps[i]);
747 fprintf(fplog, "\n\n");
750 static void print_prob(FILE *fplog, const char *leg, int n, real *prob)
755 fprintf(fplog, "Repl %2s ", leg);
756 for (i = 1; i < n; i++)
760 sprintf(buf, "%4.2f", prob[i]);
761 fprintf(fplog, " %3s", buf[0] == '1' ? "1.0" : buf+1);
768 fprintf(fplog, "\n");
771 static void print_count(FILE *fplog, const char *leg, int n, int *count)
775 fprintf(fplog, "Repl %2s ", leg);
776 for (i = 1; i < n; i++)
778 fprintf(fplog, " %4d", count[i]);
780 fprintf(fplog, "\n");
783 static real calc_delta(FILE *fplog, gmx_bool bPrint, struct gmx_repl_ex *re, int a, int b, int ap, int bp)
786 real ediff, dpV, delta = 0;
787 real *Epot = re->Epot;
790 real *beta = re->beta;
792 /* Two cases; we are permuted and not. In all cases, setting ap = a and bp = b will reduce
793 to the non permuted case */
799 * Okabe et. al. Chem. Phys. Lett. 335 (2001) 435-439
801 ediff = Epot[b] - Epot[a];
802 delta = -(beta[bp] - beta[ap])*ediff;
805 /* two cases: when we are permuted, and not. */
807 ediff = E_new - E_old
808 = [H_b(x_a) + H_a(x_b)] - [H_b(x_b) + H_a(x_a)]
809 = [H_b(x_a) - H_a(x_a)] + [H_a(x_b) - H_b(x_b)]
810 = de[b][a] + de[a][b] */
813 ediff = E_new - E_old
814 = [H_bp(x_a) + H_ap(x_b)] - [H_bp(x_b) + H_ap(x_a)]
815 = [H_bp(x_a) - H_ap(x_a)] + [H_ap(x_b) - H_bp(x_b)]
816 = [H_bp(x_a) - H_a(x_a) + H_a(x_a) - H_ap(x_a)] + [H_ap(x_b) - H_b(x_b) + H_b(x_b) - H_bp(x_b)]
817 = [H_bp(x_a) - H_a(x_a)] - [H_ap(x_a) - H_a(x_a)] + [H_ap(x_b) - H_b(x_b)] - H_bp(x_b) - H_b(x_b)]
818 = (de[bp][a] - de[ap][a]) + (de[ap][b] - de[bp][b]) */
819 /* but, in the current code implementation, we flip configurations, not indices . . .
820 So let's examine that.
821 = [H_b(x_ap) - H_a(x_a)] - [H_a(x_ap) - H_a(x_a)] + [H_a(x_bp) - H_b(x_b)] - H_b(x_bp) - H_b(x_b)]
822 = [H_b(x_ap) - H_a(x_ap)] + [H_a(x_bp) - H_b(x_pb)]
823 = (de[b][ap] - de[a][ap]) + (de[a][bp] - de[b][bp]
824 So, if we exchange b<=> bp and a<=> ap, we return to the same result.
825 So the simple solution is to flip the
826 position of perturbed and original indices in the tests.
829 ediff = (de[bp][a] - de[ap][a]) + (de[ap][b] - de[bp][b]);
830 delta = ediff*beta[a]; /* assume all same temperature in this case */
834 /* delta = reduced E_new - reduced E_old
835 = [beta_b H_b(x_a) + beta_a H_a(x_b)] - [beta_b H_b(x_b) + beta_a H_a(x_a)]
836 = [beta_b H_b(x_a) - beta_a H_a(x_a)] + [beta_a H_a(x_b) - beta_b H_b(x_b)]
837 = [beta_b dH_b(x_a) + beta_b H_a(x_a) - beta_a H_a(x_a)] +
838 [beta_a dH_a(x_b) + beta_a H_b(x_b) - beta_b H_b(x_b)]
839 = [beta_b dH_b(x_a) + [beta_a dH_a(x_b) +
840 beta_b (H_a(x_a) - H_b(x_b)]) - beta_a (H_a(x_a) - H_b(x_b))
841 = beta_b dH_b(x_a) + beta_a dH_a(x_b) - (beta_b - beta_a)(H_b(x_b) - H_a(x_a) */
842 /* delta = beta[b]*de[b][a] + beta[a]*de[a][b] - (beta[b] - beta[a])*(Epot[b] - Epot[a]; */
843 /* permuted (big breath!) */
844 /* delta = reduced E_new - reduced E_old
845 = [beta_bp H_bp(x_a) + beta_ap H_ap(x_b)] - [beta_bp H_bp(x_b) + beta_ap H_ap(x_a)]
846 = [beta_bp H_bp(x_a) - beta_ap H_ap(x_a)] + [beta_ap H_ap(x_b) - beta_bp H_bp(x_b)]
847 = [beta_bp H_bp(x_a) - beta_ap H_ap(x_a)] + [beta_ap H_ap(x_b) - beta_bp H_bp(x_b)]
848 - beta_pb H_a(x_a) + beta_ap H_a(x_a) + beta_pb H_a(x_a) - beta_ap H_a(x_a)
849 - beta_ap H_b(x_b) + beta_bp H_b(x_b) + beta_ap H_b(x_b) - beta_bp H_b(x_b)
850 = [(beta_bp H_bp(x_a) - beta_bp H_a(x_a)) - (beta_ap H_ap(x_a) - beta_ap H_a(x_a))] +
851 [(beta_ap H_ap(x_b) - beta_ap H_b(x_b)) - (beta_bp H_bp(x_b) - beta_bp H_b(x_b))]
852 + beta_pb H_a(x_a) - beta_ap H_a(x_a) + beta_ap H_b(x_b) - beta_bp H_b(x_b)
853 = [beta_bp (H_bp(x_a) - H_a(x_a)) - beta_ap (H_ap(x_a) - H_a(x_a))] +
854 [beta_ap (H_ap(x_b) - H_b(x_b)) - beta_bp (H_bp(x_b) - H_b(x_b))]
855 + beta_pb (H_a(x_a) - H_b(x_b)) - beta_ap (H_a(x_a) - H_b(x_b))
856 = ([beta_bp de[bp][a] - beta_ap de[ap][a]) + beta_ap de[ap][b] - beta_bp de[bp][b])
857 + (beta_pb-beta_ap)(H_a(x_a) - H_b(x_b)) */
858 delta = beta[bp]*(de[bp][a] - de[bp][b]) + beta[ap]*(de[ap][b] - de[ap][a]) - (beta[bp]-beta[ap])*(Epot[b]-Epot[a]);
861 gmx_incons("Unknown replica exchange quantity");
865 fprintf(fplog, "Repl %d <-> %d dE_term = %10.3e (kT)\n", a, b, delta);
869 /* revist the calculation for 5.0. Might be some improvements. */
870 dpV = (beta[ap]*re->pres[ap]-beta[bp]*re->pres[bp])*(Vol[b]-Vol[a])/PRESFAC;
873 fprintf(fplog, " dpV = %10.3e d = %10.3e\nb", dpV, delta + dpV);
881 test_for_replica_exchange(FILE *fplog,
882 const gmx_multisim_t *ms,
883 struct gmx_repl_ex *re,
884 gmx_enerdata_t *enerd,
889 int m, i, j, a, b, ap, bp, i0, i1, tmp;
890 real ediff = 0, delta = 0, dpV = 0;
891 gmx_bool bPrint, bMultiEx;
892 gmx_bool *bEx = re->bEx;
893 real *prob = re->prob;
894 int *pind = re->destinations; /* permuted index */
895 gmx_bool bEpot = FALSE;
896 gmx_bool bDLambda = FALSE;
897 gmx_bool bVol = FALSE;
900 bMultiEx = (re->nex > 1); /* multiple exchanges at each state */
901 fprintf(fplog, "Replica exchange at step " "%"GMX_PRId64 " time %g\n", step, time);
905 for (i = 0; i < re->nrepl; i++)
910 re->Vol[re->repl] = vol;
912 if ((re->type == ereTEMP || re->type == ereTL))
914 for (i = 0; i < re->nrepl; i++)
919 re->Epot[re->repl] = enerd->term[F_EPOT];
920 /* temperatures of different states*/
921 for (i = 0; i < re->nrepl; i++)
923 re->beta[i] = 1.0/(re->q[ereTEMP][i]*BOLTZ);
928 for (i = 0; i < re->nrepl; i++)
930 re->beta[i] = 1.0/(re->temp*BOLTZ); /* we have a single temperature */
933 if (re->type == ereLAMBDA || re->type == ereTL)
936 /* lambda differences. */
937 /* de[i][j] is the energy of the jth simulation in the ith Hamiltonian
938 minus the energy of the jth simulation in the jth Hamiltonian */
939 for (i = 0; i < re->nrepl; i++)
941 for (j = 0; j < re->nrepl; j++)
946 for (i = 0; i < re->nrepl; i++)
948 re->de[i][re->repl] = (enerd->enerpart_lambda[(int)re->q[ereLAMBDA][i]+1]-enerd->enerpart_lambda[0]);
952 /* now actually do the communication */
955 gmx_sum_sim(re->nrepl, re->Vol, ms);
959 gmx_sum_sim(re->nrepl, re->Epot, ms);
963 for (i = 0; i < re->nrepl; i++)
965 gmx_sum_sim(re->nrepl, re->de[i], ms);
969 /* make a duplicate set of indices for shuffling */
970 for (i = 0; i < re->nrepl; i++)
972 pind[i] = re->ind[i];
977 /* multiple random switch exchange */
979 for (i = 0; i < re->nex + nself; i++)
983 gmx_rng_cycle_2uniform(step, i*2, re->seed, RND_SEED_REPLEX, rnd);
984 /* randomly select a pair */
985 /* in theory, could reduce this by identifying only which switches had a nonneglibible
986 probability of occurring (log p > -100) and only operate on those switches */
987 /* find out which state it is from, and what label that state currently has. Likely
988 more work that useful. */
989 i0 = (int)(re->nrepl*rnd[0]);
990 i1 = (int)(re->nrepl*rnd[1]);
994 continue; /* self-exchange, back up and do it again */
997 a = re->ind[i0]; /* what are the indices of these states? */
1002 bPrint = FALSE; /* too noisy */
1003 /* calculate the energy difference */
1004 /* if the code changes to flip the STATES, rather than the configurations,
1005 use the commented version of the code */
1006 /* delta = calc_delta(fplog,bPrint,re,a,b,ap,bp); */
1007 delta = calc_delta(fplog, bPrint, re, ap, bp, a, b);
1009 /* we actually only use the first space in the prob and bEx array,
1010 since there are actually many switches between pairs. */
1020 if (delta > PROBABILITYCUTOFF)
1026 prob[0] = exp(-delta);
1028 /* roll a number to determine if accepted */
1029 gmx_rng_cycle_2uniform(step, i*2+1, re->seed, RND_SEED_REPLEX, rnd);
1030 bEx[0] = rnd[0] < prob[0];
1032 re->prob_sum[0] += prob[0];
1036 /* swap the states */
1038 pind[i0] = pind[i1];
1042 re->nattempt[0]++; /* keep track of total permutation trials here */
1043 print_allswitchind(fplog, re->nrepl, pind, re->allswaps, re->tmpswap);
1047 /* standard nearest neighbor replica exchange */
1049 m = (step / re->nst) % 2;
1050 for (i = 1; i < re->nrepl; i++)
1055 bPrint = (re->repl == a || re->repl == b);
1058 delta = calc_delta(fplog, bPrint, re, a, b, a, b);
1069 if (delta > PROBABILITYCUTOFF)
1075 prob[i] = exp(-delta);
1077 /* roll a number to determine if accepted */
1078 gmx_rng_cycle_2uniform(step, i, re->seed, RND_SEED_REPLEX, rnd);
1079 bEx[i] = rnd[0] < prob[i];
1081 re->prob_sum[i] += prob[i];
1085 /* swap these two */
1087 pind[i-1] = pind[i];
1089 re->nexchange[i]++; /* statistics for back compatibility */
1098 /* print some statistics */
1099 print_ind(fplog, "ex", re->nrepl, re->ind, bEx);
1100 print_prob(fplog, "pr", re->nrepl, prob);
1101 fprintf(fplog, "\n");
1105 /* record which moves were made and accepted */
1106 for (i = 0; i < re->nrepl; i++)
1108 re->nmoves[re->ind[i]][pind[i]] += 1;
1109 re->nmoves[pind[i]][re->ind[i]] += 1;
1111 fflush(fplog); /* make sure we can see what the last exchange was */
1114 static void write_debug_x(t_state *state)
1120 for (i = 0; i < state->natoms; i += 10)
1122 fprintf(debug, "dx %5d %10.5f %10.5f %10.5f\n", i, state->x[i][XX], state->x[i][YY], state->x[i][ZZ]);
1128 cyclic_decomposition(const int *destinations,
1137 for (i = 0; i < nrepl; i++)
1141 for (i = 0; i < nrepl; i++) /* one cycle for each replica */
1152 for (j = 0; j < nrepl; j++) /* potentially all cycles are part, but we will break first */
1154 p = destinations[p]; /* start permuting */
1162 break; /* we've reached the original element, the cycle is complete, and we marked the end. */
1166 cyclic[i][c] = p; /* each permutation gives a new member of the cycle */
1172 *nswap = maxlen - 1;
1176 for (i = 0; i < nrepl; i++)
1178 fprintf(debug, "Cycle %d:", i);
1179 for (j = 0; j < nrepl; j++)
1181 if (cyclic[i][j] < 0)
1185 fprintf(debug, "%2d", cyclic[i][j]);
1187 fprintf(debug, "\n");
1194 compute_exchange_order(FILE *fplog,
1202 for (j = 0; j < maxswap; j++)
1204 for (i = 0; i < nrepl; i++)
1206 if (cyclic[i][j+1] >= 0)
1208 order[cyclic[i][j+1]][j] = cyclic[i][j];
1209 order[cyclic[i][j]][j] = cyclic[i][j+1];
1212 for (i = 0; i < nrepl; i++)
1214 if (order[i][j] < 0)
1216 order[i][j] = i; /* if it's not exchanging, it should stay this round*/
1223 fprintf(fplog, "Replica Exchange Order\n");
1224 for (i = 0; i < nrepl; i++)
1226 fprintf(fplog, "Replica %d:", i);
1227 for (j = 0; j < maxswap; j++)
1229 if (order[i][j] < 0)
1233 fprintf(debug, "%2d", order[i][j]);
1235 fprintf(fplog, "\n");
1242 prepare_to_do_exchange(FILE *fplog,
1243 const int *destinations,
1244 const int replica_id,
1250 gmx_bool *bThisReplicaExchanged)
1253 /* Hold the cyclic decomposition of the (multiple) replica
1255 gmx_bool bAnyReplicaExchanged = FALSE;
1256 *bThisReplicaExchanged = FALSE;
1258 for (i = 0; i < nrepl; i++)
1260 if (destinations[i] != i)
1262 /* only mark as exchanged if the index has been shuffled */
1263 bAnyReplicaExchanged = TRUE;
1267 if (bAnyReplicaExchanged)
1269 /* reinitialize the placeholder arrays */
1270 for (i = 0; i < nrepl; i++)
1272 for (j = 0; j < nrepl; j++)
1279 /* Identify the cyclic decomposition of the permutation (very
1280 * fast if neighbor replica exchange). */
1281 cyclic_decomposition(destinations, cyclic, incycle, nrepl, maxswap);
1283 /* Now translate the decomposition into a replica exchange
1284 * order at each step. */
1285 compute_exchange_order(fplog, cyclic, order, nrepl, *maxswap);
1287 /* Did this replica do any exchange at any point? */
1288 for (j = 0; j < *maxswap; j++)
1290 if (replica_id != order[replica_id][j])
1292 *bThisReplicaExchanged = TRUE;
1299 gmx_bool replica_exchange(FILE *fplog, const t_commrec *cr, struct gmx_repl_ex *re,
1300 t_state *state, gmx_enerdata_t *enerd,
1301 t_state *state_local, gmx_int64_t step, real time)
1305 int exchange_partner;
1307 /* Number of rounds of exchanges needed to deal with any multiple
1309 /* Where each replica ends up after the exchange attempt(s). */
1310 /* The order in which multiple exchanges will occur. */
1311 gmx_bool bThisReplicaExchanged = FALSE;
1315 replica_id = re->repl;
1316 test_for_replica_exchange(fplog, cr->ms, re, enerd, det(state_local->box), step, time);
1317 prepare_to_do_exchange(fplog, re->destinations, replica_id, re->nrepl, &maxswap,
1318 re->order, re->cyclic, re->incycle, &bThisReplicaExchanged);
1320 /* Do intra-simulation broadcast so all processors belonging to
1321 * each simulation know whether they need to participate in
1322 * collecting the state. Otherwise, they might as well get on with
1323 * the next thing to do. */
1324 if (DOMAINDECOMP(cr))
1327 MPI_Bcast(&bThisReplicaExchanged, sizeof(gmx_bool), MPI_BYTE, MASTERRANK(cr),
1328 cr->mpi_comm_mygroup);
1332 if (bThisReplicaExchanged)
1334 /* Exchange the states */
1335 /* Collect the global state on the master node */
1336 if (DOMAINDECOMP(cr))
1338 dd_collect_state(cr->dd, state_local, state);
1342 copy_state_nonatomdata(state_local, state);
1347 /* There will be only one swap cycle with standard replica
1348 * exchange, but there may be multiple swap cycles if we
1349 * allow multiple swaps. */
1351 for (j = 0; j < maxswap; j++)
1353 exchange_partner = re->order[replica_id][j];
1355 if (exchange_partner != replica_id)
1357 /* Exchange the global states between the master nodes */
1360 fprintf(debug, "Exchanging %d with %d\n", replica_id, exchange_partner);
1362 exchange_state(cr->ms, exchange_partner, state);
1365 /* For temperature-type replica exchange, we need to scale
1366 * the velocities. */
1367 if (re->type == ereTEMP || re->type == ereTL)
1369 scale_velocities(state, sqrt(re->q[ereTEMP][replica_id]/re->q[ereTEMP][re->destinations[replica_id]]));
1374 /* With domain decomposition the global state is distributed later */
1375 if (!DOMAINDECOMP(cr))
1377 /* Copy the global state to the local state data structure */
1378 copy_state_nonatomdata(state, state_local);
1382 return bThisReplicaExchanged;
1385 void print_replica_exchange_statistics(FILE *fplog, struct gmx_repl_ex *re)
1389 fprintf(fplog, "\nReplica exchange statistics\n");
1393 fprintf(fplog, "Repl %d attempts, %d odd, %d even\n",
1394 re->nattempt[0]+re->nattempt[1], re->nattempt[1], re->nattempt[0]);
1396 fprintf(fplog, "Repl average probabilities:\n");
1397 for (i = 1; i < re->nrepl; i++)
1399 if (re->nattempt[i%2] == 0)
1405 re->prob[i] = re->prob_sum[i]/re->nattempt[i%2];
1408 print_ind(fplog, "", re->nrepl, re->ind, NULL);
1409 print_prob(fplog, "", re->nrepl, re->prob);
1411 fprintf(fplog, "Repl number of exchanges:\n");
1412 print_ind(fplog, "", re->nrepl, re->ind, NULL);
1413 print_count(fplog, "", re->nrepl, re->nexchange);
1415 fprintf(fplog, "Repl average number of exchanges:\n");
1416 for (i = 1; i < re->nrepl; i++)
1418 if (re->nattempt[i%2] == 0)
1424 re->prob[i] = ((real)re->nexchange[i])/re->nattempt[i%2];
1427 print_ind(fplog, "", re->nrepl, re->ind, NULL);
1428 print_prob(fplog, "", re->nrepl, re->prob);
1430 fprintf(fplog, "\n");
1432 /* print the transition matrix */
1433 print_transition_matrix(fplog, re->nrepl, re->nmoves, re->nattempt);