[gmx-users] Slow Runs

Justin A. Lemkul jalemkul at vt.edu
Fri Jan 28 20:46:05 CET 2011



Denny Frost wrote:
> gromacs 4.5.1
> 

Ah, what I posted was from 4.0.7.  I wonder why that sort of output was 
eliminated in 4.5; it's quite useful.  Sorry for leading you astray on that.  No 
matter, the end of the .log file will still contain statistics about what's 
eating up all your simulation time.

-Justin

> On Fri, Jan 28, 2011 at 12:40 PM, Erik Marklund <erikm at xray.bmc.uu.se 
> <mailto:erikm at xray.bmc.uu.se>> wrote:
> 
>     PME is still an Ewald sum.
> 
>     Erik
> 
>     Denny Frost skrev 2011-01-28 20.38:
>>     I don't have any domain decomposition information like that in my
>>     log file.  That's worrisome.  The only other information I could
>>     find about PME and Ewald and this set of lines:
>>
>>     Table routines are used for coulomb: TRUE
>>     Table routines are used for vdw:     FALSE
>>     Will do PME sum in reciprocal space.
>>
>>     ++++ PLEASE READ AND CITE THE FOLLOWING REFERENCE ++++
>>     U. Essman, L. Perela, M. L. Berkowitz, T. Darden, H. Lee and L. G.
>>     Pedersen 
>>     A smooth particle mesh Ewald method
>>     J. Chem. Phys. 103 (1995) pp. 8577-8592
>>     -------- -------- --- Thank You --- -------- --------
>>
>>     Will do ordinary reciprocal space Ewald sum.
>>     Using a Gaussian width (1/beta) of 0.384195 nm for Ewald
>>     Cut-off's:   NS: 1.2   Coulomb: 1.2   LJ: 1.2
>>     System total charge: 0.000
>>     Generated table with 4400 data points for Ewald.
>>     Tabscale = 2000 points/nm
>>     Generated table with 4400 data points for LJ6.
>>     Tabscale = 2000 points/nm
>>     Generated table with 4400 data points for LJ12.
>>     Tabscale = 2000 points/nm
>>     Configuring nonbonded kernels...
>>     Configuring standard C nonbonded kernels...
>>     Testing x86_64 SSE2 support... present.
>>
>>
>>     Why does it say it will do PME on one line, then ordinary Ewald later?
>>
>>     On Fri, Jan 28, 2011 at 12:26 PM, Justin A. Lemkul
>>     <jalemkul at vt.edu <mailto:jalemkul at vt.edu>> wrote:
>>
>>
>>
>>         Denny Frost wrote:
>>
>>             I just realized that that was a very old mdp file.  Here
>>             is an mdp file from my most recent run as well as what I
>>             think are the domain decomposition statistics.
>>
>>             mdp file:
>>             title               =  BMIM+PF6
>>             cpp                 =  /lib/cpp
>>             constraints         =  hbonds
>>             integrator          =  md
>>             dt                  =  0.002   ; ps !
>>             nsteps              =  4000000   ; total 8ns.
>>             nstcomm             =  1
>>             nstxout             =  50000
>>             nstvout             =  50000
>>             nstfout             =  0
>>             nstlog              =  5000
>>             nstenergy           =  5000
>>             nstxtcout           =  25000
>>             nstlist             =  10
>>             ns_type             =  grid
>>             pbc                 =  xyz
>>             coulombtype         =  PME
>>             vdwtype             =  Cut-off
>>             rlist               =  1.2
>>             rcoulomb            =  1.2
>>             rvdw                =  1.2
>>             fourierspacing      =  0.12
>>             pme_order           =  4
>>             ewald_rtol          =  1e-5
>>             ; Berendsen temperature coupling is on in two groups
>>             Tcoupl              =  berendsen
>>             tc_grps             =  BMI      PF6      tau_t            
>>               =  0.2  0.2
>>             ref_t               =  300  300
>>             nsttcouple          =  1
>>             ; Energy monitoring
>>             energygrps          =  BMI      PF6
>>             ; Isotropic pressure coupling is now on
>>             Pcoupl              =  berendsen
>>             pcoupltype          =  isotropic
>>             ;pc-grps             =  BMI      PFF
>>             tau_p               =  1.0
>>             ref_p               =  1.0
>>             compressibility     =  4.5e-5
>>
>>             ; Generate velocites is off at 300 K.
>>             gen_vel             =  yes
>>             gen_temp            =  300.0
>>             gen_seed            =  100000
>>
>>             domain decomposition
>>             There are: 12800 Atoms
>>             Max number of connections per atom is 63
>>             Total number of connections is 286400
>>             Max number of graph edges per atom is 6
>>             Total number of graph edges is 24800
>>
>>
>>         More useful information is contained at the very top of the
>>         .log file, after the citations.  An example from one of my own
>>         runs is:
>>
>>         Linking all bonded interactions to atoms
>>         There are 2772 inter charge-group exclusions,
>>         will use an extra communication step for exclusion forces for PME
>>
>>         The initial number of communication pulses is: X 2 Y 1
>>         The initial domain decomposition cell size is: X 1.05 nm Y 1.58 nm
>>
>>         The maximum allowed distance for charge groups involved in
>>         interactions is:
>>                         non-bonded interactions           1.400 nm
>>         (the following are initial values, they could change due to
>>         box deformation)
>>                    two-body bonded interactions  (-rdd)   1.400 nm
>>                  multi-body bonded interactions  (-rdd)   1.054 nm
>>          atoms separated by up to 5 constraints  (-rcon)  1.054 nm
>>
>>         When dynamic load balancing gets turned on, these settings
>>         will change to:
>>         The maximum number of communication pulses is: X 2 Y 2
>>         The minimum size for domain decomposition cells is 0.833 nm
>>         The requested allowed shrink of DD cells (option -dds) is: 0.80
>>         The allowed shrink of domain decomposition cells is: X 0.79 Y 0.53
>>         The maximum allowed distance for charge groups involved in
>>         interactions is:
>>                         non-bonded interactions           1.400 nm
>>                    two-body bonded interactions  (-rdd)   1.400 nm
>>                  multi-body bonded interactions  (-rdd)   0.833 nm
>>          atoms separated by up to 5 constraints  (-rcon)  0.833 nm
>>
>>
>>         Making 2D domain decomposition grid 9 x 6 x 1, home cell index
>>         0 0 0
>>
>>
>>         Also, the output under "DOMAIN DECOMPOSITION STATISTICS" (at
>>         the bottom of the file) would be useful.  Also look for any
>>         notes about performance lost due to imbalance, waiting for
>>         PME, etc.  These provide very detailed clues about how your
>>         system was treated.
>>
>>         -Justin
>>
>>
>>         -- 
>>         ========================================
>>
>>         Justin A. Lemkul
>>         Ph.D. Candidate
>>         ICTAS Doctoral Scholar
>>         MILES-IGERT Trainee
>>         Department of Biochemistry
>>         Virginia Tech
>>         Blacksburg, VA
>>         jalemkul[at]vt.edu <http://vt.edu> | (540) 231-9080
>>         http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin
>>
>>         ========================================
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>>
> 
> 
>     -- 
>     -----------------------------------------------
>     Erik Marklund, PhD student
>     Dept. of Cell and Molecular Biology, Uppsala University.
>     Husargatan 3, Box 596,    75124 Uppsala, Sweden
>     phone:    +46 18 471 4537        fax: +46 18 511 755
>     erikm at xray.bmc.uu.se <mailto:erikm at xray.bmc.uu.se>    http://folding.bmc.uu.se/
> 
> 
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-- 
========================================

Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
MILES-IGERT Trainee
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin

========================================



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