gmx_bool replica_exchange(FILE *fplog, const t_commrec *cr, struct gmx_repl_ex *re,
t_state *state, gmx_enerdata_t *enerd,
t_state *state_local, gmx_int64_t step, real time)
{
int i, j;
int replica_id = 0;
int exchange_partner;
int maxswap = 0;
/* Number of rounds of exchanges needed to deal with any multiple
* exchanges. */
/* Where each replica ends up after the exchange attempt(s). */
/* The order in which multiple exchanges will occur. */
gmx_bool bThisReplicaExchanged = FALSE;
if (MASTER(cr))
{
replica_id = re->repl;
test_for_replica_exchange(fplog, cr->ms, re, enerd, det(state_local->box), step, time);
prepare_to_do_exchange(fplog, re->destinations, replica_id, re->nrepl, &maxswap,
re->order, re->cyclic, re->incycle, &bThisReplicaExchanged);
}
/* Do intra-simulation broadcast so all processors belonging to
* each simulation know whether they need to participate in
* collecting the state. Otherwise, they might as well get on with
* the next thing to do. */
if (DOMAINDECOMP(cr))
{
#ifdef GMX_MPI
MPI_Bcast(&bThisReplicaExchanged, sizeof(gmx_bool), MPI_BYTE, MASTERRANK(cr),
cr->mpi_comm_mygroup);
#endif
}
if (bThisReplicaExchanged)
{
/* Exchange the states */
/* Collect the global state on the master node */
if (DOMAINDECOMP(cr))
{
dd_collect_state(cr->dd, state_local, state);
}
else
{
copy_state_nonatomdata(state_local, state);
}
if (MASTER(cr))
{
/* There will be only one swap cycle with standard replica
* exchange, but there may be multiple swap cycles if we
* allow multiple swaps. */
for (j = 0; j < maxswap; j++)
{
exchange_partner = re->order[replica_id][j];
if (exchange_partner != replica_id)
{
/* Exchange the global states between the master nodes */
if (debug)
{
fprintf(debug, "Exchanging %d with %d\n", replica_id, exchange_partner);
}
exchange_state(cr->ms, exchange_partner, state);
}
}
/* For temperature-type replica exchange, we need to scale
* the velocities. */
if (re->type == ereTEMP || re->type == ereTL)
{
scale_velocities(state, sqrt(re->q[ereTEMP][replica_id]/re->q[ereTEMP][re->destinations[replica_id]]));
}
}
/* With domain decomposition the global state is distributed later */
if (!DOMAINDECOMP(cr))
{
/* Copy the global state to the local state data structure */
copy_state_nonatomdata(state, state_local);
}
}
return bThisReplicaExchanged;
}
gmx_bool replica_exchange(FILE *fplog,const t_commrec *cr,struct gmx_repl_ex *re,
t_state *state,real *ener,
t_state *state_local,
int step,real time)
{
gmx_multisim_t *ms;
int exchange=-1,shift;
gmx_bool bExchanged=FALSE;
ms = cr->ms;
if (MASTER(cr))
{
exchange = get_replica_exchange(fplog,ms,re,ener,det(state->box),
step,time);
bExchanged = (exchange >= 0);
}
if (PAR(cr))
{
#ifdef GMX_MPI
MPI_Bcast(&bExchanged,sizeof(gmx_bool),MPI_BYTE,MASTERRANK(cr),
cr->mpi_comm_mygroup);
#endif
}
if (bExchanged)
{
/* Exchange the states */
if (PAR(cr))
{
/* Collect the global state on the master node */
if (DOMAINDECOMP(cr))
{
dd_collect_state(cr->dd,state_local,state);
}
else
{
pd_collect_state(cr,state);
}
}
if (MASTER(cr))
{
/* Exchange the global states between the master nodes */
if (debug)
{
fprintf(debug,"Exchanging %d with %d\n",ms->sim,exchange);
}
exchange_state(ms,exchange,state);
if (re->type == ereTEMP)
{
scale_velocities(state,sqrt(re->q[ms->sim]/re->q[exchange]));
}
}
/* With domain decomposition the global state is distributed later */
if (!DOMAINDECOMP(cr))
{
/* Copy the global state to the local state data structure */
copy_state_nonatomdata(state,state_local);
if (PAR(cr))
{
bcast_state(cr,state,FALSE);
}
}
}
return bExchanged;
}