113 lines
3.6 KiB
C++
113 lines
3.6 KiB
C++
/* ----------------------------------------------------------------------
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LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
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https://www.lammps.org/, Sandia National Laboratories
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LAMMPS development team: developers@lammps.org
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Copyright (2003) Sandia Corporation. Under the terms of Contract
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DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
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certain rights in this software. This software is distributed under
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the GNU General Public License.
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See the README file in the top-level LAMMPS directory.
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------------------------------------------------------------------------- */
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#include "imbalance_time.h"
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#include "atom.h"
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#include "error.h"
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#include "timer.h"
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using namespace LAMMPS_NS;
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static constexpr double BIG = 1.0e20;
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/* -------------------------------------------------------------------- */
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ImbalanceTime::ImbalanceTime(LAMMPS *lmp) : Imbalance(lmp) {}
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/* -------------------------------------------------------------------- */
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int ImbalanceTime::options(int narg, char **arg)
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{
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if (narg < 1) error->all(FLERR, "Illegal balance weight command");
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factor = utils::numeric(FLERR, arg[0], false, lmp);
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if (factor <= 0.0) error->all(FLERR, "Illegal balance weight command");
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return 1;
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}
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/* ----------------------------------------------------------------------
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reset last and timers if necessary
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------------------------------------------------------------------------- */
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void ImbalanceTime::init(int flag)
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{
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last = 0.0;
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// flag = 1 if called from FixBalance at start of run
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// init Timer, so accumulated time not carried over from previous run
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// should NOT init Timer if called from Balance, it uses time from last run
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if (flag) timer->init();
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}
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/* -------------------------------------------------------------------- */
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void ImbalanceTime::compute(double *weight)
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{
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if (!timer->has_normal()) return;
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// cost = CPU time for relevant timers since last invocation
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// localwt = weight assigned to each owned atom
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// just return if no time yet tallied
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// we 0.1 seconds as a minimum time to avoid computation of bogus
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// load balancing weights due to limited timer resolution/precision
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double cost = -last;
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cost += timer->get_wall(Timer::PAIR);
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cost += timer->get_wall(Timer::NEIGH);
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cost += timer->get_wall(Timer::BOND);
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cost += timer->get_wall(Timer::KSPACE);
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cost += 0.1;
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double maxcost;
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MPI_Allreduce(&cost, &maxcost, 1, MPI_DOUBLE, MPI_MAX, world);
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if (maxcost <= 0.1) return;
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int nlocal = atom->nlocal;
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double localwt = 0.0;
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if (nlocal) localwt = cost / nlocal;
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if (nlocal && localwt <= 0.0) error->one(FLERR, "Balance weight <= 0.0");
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// apply factor if specified != 1.0
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// wtlo,wthi = lo/hi values excluding 0.0 due to no atoms on this proc
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// lo value does not change
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// newhi = new hi value to give hi/lo ratio factor times larger/smaller
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// expand/contract all localwt values from lo->hi to lo->newhi
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if (factor != 1.0) {
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double wtlo, wthi;
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if (localwt == 0.0) localwt = BIG;
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MPI_Allreduce(&localwt, &wtlo, 1, MPI_DOUBLE, MPI_MIN, world);
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if (localwt == BIG) localwt = 0.0;
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MPI_Allreduce(&localwt, &wthi, 1, MPI_DOUBLE, MPI_MAX, world);
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if (wtlo == wthi) return;
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double newhi = wthi * factor;
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localwt = wtlo + ((localwt - wtlo) / (wthi - wtlo)) * (newhi - wtlo);
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}
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for (int i = 0; i < nlocal; i++) weight[i] *= localwt;
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// record time up to this point
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last += cost;
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}
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/* -------------------------------------------------------------------- */
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std::string ImbalanceTime::info()
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{
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return fmt::format(" time weight factor: {}\n", factor);
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}
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