[gmx-users] Problem with incorrect GB-Polarization Energy Value

Mark Abraham Mark.Abraham at anu.edu.au
Wed Aug 29 17:38:24 CEST 2012


On 08/30/2012 01:11 AM, jesmin jahan wrote:
> Thanks Mark for your reply.
>
> For the time being, I admit your claim that I am comparing apple with orange.
> So, to investigate more, I run the simulation without any modification
> in parameter fields and force field I am using. My test data is CMV
> virus shell.
> I am using the following commands.
>
> pdb2gmx -f 1F15-full.pdb -ter -ignh -ff amber99 -water none
> grompp -f mdr.mdp -c conf.gro -p topol.top -o imd.tpr

This would generate a .top that had bonded interactions, which your 
output claims you did not have. I think you are not doing what you say 
above. The .top I suggested you construct for your *reruns* would avoid 
calculating terms whose timing you didn't want to measure, but their 
absence breaks the model physics and would lead to symptoms like you 
report below. I think you're using the modified top, not a fresh one 
from pdb2gmx.

Further I'd strongly suggest using 4.5.5 until such time as a beta 
release of 4.6 comes out. Until then, you're admitting you're playing 
with fire and you know what you're doing, which is dangerous for 
everybody, but particularly so for someone new to GROMACS and who hasn't 
followed the development history. Getting timing results for 4.5.5 can 
be taken to the bank, and will provide you (and maybe others) a 
benchmark for comparing to 4.6 when the time comes. You'll have to re-do 
any work done with the 4.6 development branch then anyway.

Mark

> OMP_NUM_THREADS=12 mdrun -nt 16 -s imd.tpr
>
>
> The log file looks like this:
>   :-)  G  R  O  M  A  C  S  (-:
>
>                     GROningen MAchine for Chemical Simulation
>
>                     :-)  VERSION 4.6-dev-20120820-87e5bcf  (-:
>
>          Written by Emile Apol, Rossen Apostolov, Herman J.C. Berendsen,
>        Aldert van Buuren, Pär Bjelkmar, Rudi van Drunen, Anton Feenstra,
>          Gerrit Groenhof, Peter Kasson, Per Larsson, Pieter Meulenhoff,
>             Teemu Murtola, Szilard Pall, Sander Pronk, Roland Schulz,
>                  Michael Shirts, Alfons Sijbers, Peter Tieleman,
>
>                 Berk Hess, David van der Spoel, and Erik Lindahl.
>
>         Copyright (c) 1991-2000, University of Groningen, The Netherlands.
>              Copyright (c) 2001-2010, The GROMACS development team at
>          Uppsala University & The Royal Institute of Technology, Sweden.
>              check out http://www.gromacs.org for more information.
>
>           This program is free software; you can redistribute it and/or
>            modify it under the terms of the GNU General Public License
>           as published by the Free Software Foundation; either version 2
>               of the License, or (at your option) any later version.
>
>                                :-)  mdrun_mpi  (-:
>
>
> ++++ PLEASE READ AND CITE THE FOLLOWING REFERENCE ++++
> B. Hess and C. Kutzner and D. van der Spoel and E. Lindahl
> GROMACS 4: Algorithms for highly efficient, load-balanced, and scalable
> molecular simulation
> J. Chem. Theory Comput. 4 (2008) pp. 435-447
> -------- -------- --- Thank You --- -------- --------
>
>
> ++++ PLEASE READ AND CITE THE FOLLOWING REFERENCE ++++
> D. van der Spoel, E. Lindahl, B. Hess, G. Groenhof, A. E. Mark and H. J. C.
> Berendsen
> GROMACS: Fast, Flexible and Free
> J. Comp. Chem. 26 (2005) pp. 1701-1719
> -------- -------- --- Thank You --- -------- --------
>
>
> ++++ PLEASE READ AND CITE THE FOLLOWING REFERENCE ++++
> E. Lindahl and B. Hess and D. van der Spoel
> GROMACS 3.0: A package for molecular simulation and trajectory analysis
> J. Mol. Mod. 7 (2001) pp. 306-317
> -------- -------- --- Thank You --- -------- --------
>
>
> ++++ PLEASE READ AND CITE THE FOLLOWING REFERENCE ++++
> H. J. C. Berendsen, D. van der Spoel and R. van Drunen
> GROMACS: A message-passing parallel molecular dynamics implementation
> Comp. Phys. Comm. 91 (1995) pp. 43-56
> -------- -------- --- Thank You --- -------- --------
>
> Input Parameters:
>     integrator           = md
>     nsteps               = 0
>     init-step            = 0
>     ns-type              = Grid
>     nstlist              = 10
>     ndelta               = 2
>     nstcomm              = 10
>     comm-mode            = Linear
>     nstlog               = 1000
>     nstxout              = 0
>     nstvout              = 0
>     nstfout              = 0
>     nstcalcenergy        = 10
>     nstenergy            = 100
>     nstxtcout            = 0
>     init-t               = 0
>     delta-t              = 0.001
>     xtcprec              = 1000
>     nkx                  = 0
>     nky                  = 0
>     nkz                  = 0
>     pme-order            = 4
>     ewald-rtol           = 1e-05
>     ewald-geometry       = 0
>     epsilon-surface      = 0
>     optimize-fft         = FALSE
>     ePBC                 = no
>     bPeriodicMols        = FALSE
>     bContinuation        = FALSE
>     bShakeSOR            = FALSE
>     etc                  = No
>     bPrintNHChains       = FALSE
>     nsttcouple           = -1
>     epc                  = No
>     epctype              = Isotropic
>     nstpcouple           = -1
>     tau-p                = 1
>     ref-p (3x3):
>        ref-p[    0]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>        ref-p[    1]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>        ref-p[    2]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>     compress (3x3):
>        compress[    0]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>        compress[    1]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>        compress[    2]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>     refcoord-scaling     = No
>     posres-com (3):
>        posres-com[0]= 0.00000e+00
>        posres-com[1]= 0.00000e+00
>        posres-com[2]= 0.00000e+00
>     posres-comB (3):
>        posres-comB[0]= 0.00000e+00
>        posres-comB[1]= 0.00000e+00
>        posres-comB[2]= 0.00000e+00
>     rlist                = 1
>     rlistlong            = 1
>     rtpi                 = 0.05
>     coulombtype          = Cut-off
>     rcoulomb-switch      = 0
>     rcoulomb             = 1
>     vdwtype              = Cut-off
>     rvdw-switch          = 0
>     rvdw                 = 1
>     epsilon-r            = 1
>     epsilon-rf           = inf
>     tabext               = 1
>     implicit-solvent     = GBSA
>     gb-algorithm         = HCT
>     gb-epsilon-solvent   = 80
>     nstgbradii           = 1
>     rgbradii             = 1
>     gb-saltconc          = 0
>     gb-obc-alpha         = 1
>     gb-obc-beta          = 0.8
>     gb-obc-gamma         = 4.85
>     gb-dielectric-offset = 0.009
>     sa-algorithm         = None
>     sa-surface-tension   = 2.25936
>     DispCorr             = No
>     bSimTemp             = FALSE
>     free-energy          = no
>     nwall                = 0
>     wall-type            = 9-3
>     wall-atomtype[0]     = -1
>     wall-atomtype[1]     = -1
>     wall-density[0]      = 0
>     wall-density[1]      = 0
>     wall-ewald-zfac      = 3
>     pull                 = no
>     rotation             = FALSE
>     disre                = No
>     disre-weighting      = Conservative
>     disre-mixed          = FALSE
>     dr-fc                = 1000
>     dr-tau               = 0
>     nstdisreout          = 100
>     orires-fc            = 0
>     orires-tau           = 0
>     nstorireout          = 100
>     dihre-fc             = 0
>     em-stepsize          = 0.01
>     em-tol               = 10
>     niter                = 20
>     fc-stepsize          = 0
>     nstcgsteep           = 1000
>     nbfgscorr            = 10
>     ConstAlg             = Lincs
>     shake-tol            = 0.0001
>     lincs-order          = 4
>     lincs-warnangle      = 30
>     lincs-iter           = 1
>     bd-fric              = 0
>     ld-seed              = 1993
>     cos-accel            = 0
>     deform (3x3):
>        deform[    0]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>        deform[    1]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>        deform[    2]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>     adress               = FALSE
>     userint1             = 0
>     userint2             = 0
>     userint3             = 0
>     userint4             = 0
>     userreal1            = 0
>     userreal2            = 0
>     userreal3            = 0
>     userreal4            = 0
> grpopts:
>     nrdf:        9534
>     ref-t:           0
>     tau-t:           0
> anneal:          No
> ann-npoints:           0
>     acc:	           0           0           0
>     nfreeze:           N           N           N
>     energygrp-flags[  0]: 0
>     efield-x:
>        n = 0
>     efield-xt:
>        n = 0
>     efield-y:
>        n = 0
>     efield-yt:
>        n = 0
>     efield-z:
>        n = 0
>     efield-zt:
>        n = 0
>     bQMMM                = FALSE
>     QMconstraints        = 0
>     QMMMscheme           = 0
>     scalefactor          = 1
> qm-opts:
>     ngQM                 = 0
>
> Initializing Domain Decomposition on 16 nodes
> Dynamic load balancing: auto
> Will sort the charge groups at every domain (re)decomposition
> Minimum cell size due to bonded interactions: 0.000 nm
> Scaling the initial minimum size with 1/0.8 (option -dds) = 1.25
> Optimizing the DD grid for 16 cells with a minimum initial size of 0.000 nm
> Domain decomposition grid 4 x 4 x 1, separate PME nodes 0
> Domain decomposition nodeid 0, coordinates 0 0 0
>
> Detecting CPU-specific acceleration. Present hardware specification:
> Vendor: GenuineIntel
> Brand:  Intel(R) Xeon(R) CPU           X5680  @ 3.33GHz
> Family:  6  Model: 44  Stepping:  2
> Features: htt sse2 sse4.1 aes rdtscp
> Acceleration most likely to fit this hardware: SSE4.1
> Acceleration selected at Gromacs compile time: SSE4.1
>
> Table routines are used for coulomb: FALSE
> Table routines are used for vdw:     FALSE
> Cut-off's:   NS: 1   Coulomb: 1   LJ: 1
> System total charge: 6.000
> Configuring nonbonded kernels...
> Configuring standard C nonbonded kernels...
>
>
>
> Linking all bonded interactions to atoms
>
> The initial number of communication pulses is: X 2 Y 2
> The initial domain decomposition cell size is: X 0.79 nm Y 0.89 nm
>
> The maximum allowed distance for charge groups involved in interactions is:
>                   non-bonded interactions           1.000 nm
> (the following are initial values, they could change due to box deformation)
>              two-body bonded interactions  (-rdd)   1.000 nm
>            multi-body bonded interactions  (-rdd)   0.794 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 0.500 nm
> The requested allowed shrink of DD cells (option -dds) is: 0.80
> The allowed shrink of domain decomposition cells is: X 0.63 Y 0.56
> The maximum allowed distance for charge groups involved in interactions is:
>                   non-bonded interactions           1.000 nm
>              two-body bonded interactions  (-rdd)   1.000 nm
>            multi-body bonded interactions  (-rdd)   0.500 nm
>
>
> Making 2D domain decomposition grid 4 x 4 x 1, home cell index 0 0 0
>
> Center of mass motion removal mode is Linear
> We have the following groups for center of mass motion removal:
>    0:  rest
> There are: 3179 Atoms
> Charge group distribution at step 0: 84 180 252 196 237 210 255 157
> 254 197 266 176 186 104 224 201
> Grid: 4 x 4 x 4 cells
> Initial temperature: 0 K
>
> Started mdrun on node 0 Wed Aug 29 02:32:21 2012
>
>             Step           Time         Lambda
>                0        0.00000        0.00000
>
>     Energies (kJ/mol)
> GB Polarization        LJ (SR)   Coulomb (SR)      Potential    Kinetic En.
>     -1.65116e+04    5.74908e+08   -2.37699e+05    5.74654e+08    6.36009e+11
>     Total Energy    Temperature Pressure (bar)
>      6.36584e+11    1.60465e+10    0.00000e+00
>
> 	<======  ###############  ==>
> 	<====  A V E R A G E S  ====>
> 	<==  ###############  ======>
>
> 	Statistics over 1 steps using 1 frames
>
>     Energies (kJ/mol)
> GB Polarization        LJ (SR)   Coulomb (SR)      Potential    Kinetic En.
>     -1.65116e+04    5.74908e+08   -2.37699e+05    5.74654e+08    6.36009e+11
>     Total Energy    Temperature Pressure (bar)
>      6.36584e+11    1.60465e+10    0.00000e+00
>
>     Total Virial (kJ/mol)
>     -1.13687e+09    1.14300e+07   -1.23884e+07
>      1.14273e+07   -1.15125e+09   -5.31658e+06
>     -1.23830e+07   -5.31326e+06   -1.16512e+09
>
>     Pressure (bar)
>      0.00000e+00    0.00000e+00    0.00000e+00
>      0.00000e+00    0.00000e+00    0.00000e+00
>      0.00000e+00    0.00000e+00    0.00000e+00
>
>     Total Dipole (D)
>      1.35524e+03   -4.39059e+01    2.16985e+03
>
>
> 	M E G A - F L O P S   A C C O U N T I N G
>
>     RF=Reaction-Field  FE=Free Energy  SCFE=Soft-Core/Free Energy
>     T=Tabulated        W3=SPC/TIP3p    W4=TIP4p (single or pairs)
>     NF=No Forces
>
>   Computing:                               M-Number         M-Flops  % Flops
> -----------------------------------------------------------------------------
>   Generalized Born Coulomb                 0.006162           0.296     0.2
>   GB Coulomb + LJ                          0.446368          27.228    19.8
>   Outer nonbonded loop                     0.015554           0.156     0.1
>   Born radii (HCT/OBC)                     0.452530          82.813    60.3
>   Born force chain rule                    0.452530           6.788     4.9
>   NS-Pairs                                 0.940291          19.746    14.4
>   Reset In Box                             0.003179           0.010     0.0
>   CG-CoM                                   0.006358           0.019     0.0
>   Virial                                   0.003899           0.070     0.1
>   Stop-CM                                  0.006358           0.064     0.0
>   Calc-Ekin                                0.006358           0.172     0.1
> -----------------------------------------------------------------------------
>   Total                                                     137.361   100.0
> -----------------------------------------------------------------------------
>
>
>      D O M A I N   D E C O M P O S I T I O N   S T A T I S T I C S
>
>   av. #atoms communicated per step for force:  2 x 7369.0
>
>
>       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
>
>   Computing:         Nodes     Number     G-Cycles    Seconds     %
> -----------------------------------------------------------------------
>   Domain decomp.        16          1        0.210        0.1    11.4
>   Comm. coord.          16          1        0.006        0.0     0.3
>   Neighbor search       16          1        0.118        0.1     6.4
>   Force                 16          1        1.319        0.8    71.4
>   Wait + Comm. F        16          1        0.016        0.0     0.9
>   Update                16          1        0.003        0.0     0.2
>   Comm. energies        16          1        0.093        0.1     5.0
>   Rest                  16                   0.082        0.1     4.4
> -----------------------------------------------------------------------
>   Total                 16                   1.847        1.1   100.0
> -----------------------------------------------------------------------
>
> NOTE: 5 % of the run time was spent communicating energies,
>        you might want to use the -gcom option of mdrun
>
>
> 	Parallel run - timing based on wallclock.
>
>                 NODE (s)   Real (s)      (%)
>         Time:      0.036      0.036    100.0
>                 (Mnbf/s)   (GFlops)   (ns/day)  (hour/ns)
> Performance:     12.702      3.856      2.425      9.896
> Finished mdrun on node 0 Wed Aug 29 02:32:21 2012
>
>
>
> The GB- energy value reported is half of that reported by Amber 11 and
> Octree based Molecular dynamic package.
>
> Although I guess the difference can be due to the difference in
> algorithms they are using, but there could be some other reason.
> If anyone knows what are the possible reasons behind this, please let
> me know. May be fixing them will give me same value for all different
> Molecular Dynamic Package.
>
> Best Regard,
> Jesmin
>
> On Mon, Aug 27, 2012 at 6:25 PM, Mark Abraham <Mark.Abraham at anu.edu.au> wrote:
>> On 28/08/2012 2:33 AM, jesmin jahan wrote:
>>> Dear All,
>>>
>>> I am using Gromacs 4.5.3 for GB-Polarization Energy Calculation. As I
>>> am not interested to any other energy terms right now, I have set all
>>> the non-bonded parameters to 0.
>>>
>>> I am also calculating GB polarization energy using other available
>>> Molecular Dynamic Packages and doing a comparative study between them
>>> (say: Accuracy Vs. Speed Up).
>>> I have already used Gromacs for calculating GB-energy for 168
>>> different Protein molecules and the energy values reported were more
>>> or less the same as reported by others.
>>>
>>> Now, I am using a virus shell as input in this process. It contains
>>> 1.5 million atoms. Unfortunately, this time, the energy reported is
>>> almost half of the value reported by others.
>>> So, I am a little bit confused. Am I doing something wrong? I have
>>> heard previously that there is no max size for Gromacs.
>>
>> Probably you're comparing apples with oranges. Your previous reports were
>> choosing to use a cut-off in the non-bonded interactions. Perhaps some of
>> the other codes are not or cannot. That would greatly affect performance and
>> the value of the result, and is part of why it is meaningless to try to
>> extract the time for just a part of a calculation without the timing of its
>> support infrastructure (such as constructing the pair list from the
>> cut-off). Also, since you are computing on proteins, you probably have
>> bonded and VDW interactions in your force field also, and your timing
>> comparisons will be misleading if you ignore those. The time taken to
>> execute an implementation of a complex algorithm is rarely additive in its
>> parts. For example, software that makes good or bad use of the cache in a
>> real calculation won't have the opportunity to show that if the whole
>> problem size fits in the L1 cache because it's been stripped down.
>>
>> Mark
>> --
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>
>




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