[gmx-users] md.log interpretation

Nizar Masbukhin nizar.fkub08 at gmail.com
Thu Nov 6 12:46:29 CET 2014


I have tried running simulation with zero cutoff and zero nstlist and
simple ns. That was very very slow, however.

anyway thanks for the reply.
 On Nov 5, 2014 9:38 PM, "Mark Abraham" <mark.j.abraham at gmail.com> wrote:

> Hi,
>
> I am not familiar with the implementation details, but I would assume there
> is a dependency on rcoulomb of the cost of the Born force chain rule. You
> can check this by trying different values. It might be faster to use
> infinite cutoffs (see manual) so that the algorithm does not need to
> search.
>
> Mark
>
> On Tue, Nov 4, 2014 at 1:34 AM, Nizar Masbukhin <nizar.fkub08 at gmail.com>
> wrote:
>
> > Dear gromacs users,
> > I've just finished my NVT equilibration in implicit solvent. From
> md.log, i
> > see that most of time were used to calculate Forces (of Born force chain
> > rule). Could someone explain to me why calculating it takes so long?
> >
> > mdp setting:
> >
> > integrator=md
> > dt=0.004
> > nstep=2500000
> > bd-frict=50
> > rlist=5
> > rvdw=5
> > rcoulomb=5
> > nstlist=40
> > implicit-solvent=GBSA
> > gb-alogarithm=still
> > nstgbradii=40
> > gbradii=5
> > gb-epsilon-solvent=80
> > gb-salt-conc=0.2
> > sa-algorithm=ace-approximation
> > sa-surface-tension=2.05
> > constraints=all-bonds
> > constraints-algorithm=LINCS
> > lincs-order=12
> >
> >
> > md.log
> >
> > M E G A - F L O P S   A C C O U N T I N G
> >
> >  NB=Group-cutoff nonbonded kernels    NxN=N-by-N cluster Verlet kernels
> >  RF=Reaction-Field  VdW=Van der Waals  QSTab=quadratic-spline table
> >  W3=SPC/TIP3p  W4=TIP4p (single or pairs)
> >  V&F=Potential and force  V=Potential only  F=Force only
> >
> >  Computing:                               M-Number         M-Flops  %
> Flops
> >
> >
> -----------------------------------------------------------------------------
> >  NB VdW [V&F]                         32677.013279       32677.013
>  0.0
> >  NB VdW [F]                         1740991.575264     1740991.575
>  0.3
> >  NB VdW & Elec. [V&F]               1192677.312698     1192677.313
>  0.2
> >  NB VdW & Elec. [F]               106409048.599622   106409048.600
> 17.9
> >  1,4 nonbonded interactions           20035.628466     1803206.562
>  0.3
> >  Born radii (Still)                 1999216.232742    93963162.939
> 15.8
> >  Born force chain rule             25548182.811729   *383222742.176*
> > 64.4
> >  NS-Pairs                             64906.572700     1363038.027
>  0.2
> >  CG-CoM                                 205.506576         616.520
>  0.0
> >  Propers                              15168.313980     3473543.901
>  0.6
> >  Impropers                              637.980588      132699.962
>  0.0
> >  Pos. Restr.                           3830.053530      191502.676
>  0.0
> >  Virial                                  82.695471        1488.518
>  0.0
> >  Stop-CM                                 82.214752         822.148
>  0.0
> >  Calc-Ekin                              822.011152       22194.301
>  0.0
> >  Lincs                                 4696.969329      281818.160
>  0.0
> >  Lincs-Mat                           229529.791548      918119.166
>  0.2
> >  Constraint-V                          9393.938658       75151.509
>  0.0
> >  Constraint-Vir                          46.973979        1127.375
>  0.0
> >  Virtual Site 3                         615.868824       22787.146
>  0.0
> >  Virtual Site 3fd                       791.205144       75164.489
>  0.0
> >  Virtual Site 3fad                      168.761208       29701.973
>  0.0
> >  Virtual Site 3out                     1893.632256      164746.006
>  0.0
> >  Virtual Site 4fdn                      576.418152      146410.211
>  0.0
> >  (null)                                 476.315439           0.000
>  0.0
> >
> >
> -----------------------------------------------------------------------------
> >  Total                                               595265438.267
>  100.0
> >
> >
> -----------------------------------------------------------------------------
> >
> >
> >      R E A L   C Y C L E   A N D   T I M E   A C C O U N T I N G
> >
> > On 1 MPI rank
> >
> >  Computing:          Num   Num      Call    Wall time         Giga-Cycles
> >                      Ranks Threads  Count      (s)         total sum    %
> >
> >
> -----------------------------------------------------------------------------
> >  Vsite constr.          1    1    1085001      96.421        385.432
>  0.2
> >  Neighbor search        1    1      27126     915.964       3661.462
>  2.1
> >  Force                  1    1    1085001   *39317.742*     157168.118
> > 91.3
> >  Vsite spread           1    1    1095852     142.563        569.880
>  0.3
> >  Write traj.            1    1      11030     425.764       1701.942
>  1.0
> >  Update                 1    1    1085001      96.742        386.714
>  0.2
> >  Constraints            1    1    1085001    1311.720       5243.449
>  3.0
> >  Rest                                         766.404       3063.612
>  1.8
> >
> >
> -----------------------------------------------------------------------------
> >  Total                                      43073.320     172180.608
> 100.0
> >
> >
> -----------------------------------------------------------------------------
> >
> >                Core t (s)   Wall t (s)        (%)
> >        Time:    41985.828    43073.320       97.5
> >                          11h57:53
> >                  (ns/day)    (hour/ns)
> > Performance:        8.706        2.757
> > Finished mdrun on rank 0 Tue Nov  4 03:27:26 2014
> >
> >
> > I know, for someone this question is less important, but for me
> performance
> > is important.
> >
> > --
> > Thanks
> > My Best Regards, Nizar
> > Medical Faculty of Brawijaya University
> > --
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