[gmx-users] Questions regarding Polarization Energy Calculation

Mark Abraham Mark.Abraham at anu.edu.au
Sat Aug 18 05:17:18 CEST 2012


On 18/08/12, *jesmin jahan * <shraban03 at gmail.com> wrote:
> Hi Mark,
>
> Thanks for your reply.
>
> In the ffnonbonded.itp, I set all sigma and epsilon values to zero.
> So, the the LJ energy is coming as zero. But the  coulomb potential is
> non zero. What should I do to make it zero?

Each charge-charge interaction contributes both a Coulomb term and a GB 
polarization term. They're computed at nearly the same time, because 
both need the distance, so both contribute to the same timing stats. 
They show up in the different energy terms that you see. There's no way 
to separate them - and any code that can do so is probably still slower 
than GROMACS doing both.

>   Energies (kJ/mol)
> GB Polarization        LJ (SR)   Coulomb (SR)      Potential Kinetic En.
>    -2.23121e+03    0.00000e+00   -3.47729e+04   -3.70041e+04 0.00000e+00
>    Total Energy    Temperature Pressure (bar)
>    -3.70041e+04    0.00000e+00    0.00000e+00
>
>
> One more point: I am not sure whether getting the 0 for an energy
> does mean that it is not being calculated at all!

Most of GROMACS is supposed to avoid computing zero interactions. It's 
not true for the all-vs-all GB loops, which you're not using, and 
currently not true for bonded interactions. Since nobody seems likely 
would compute without LJ in a real calculation, this is not a big deal 
from GROMACS point of view. I'm still skeptical about what you're trying 
to measure. Performance of well-written code is generally not additive 
from its components. If you're later going to be computing on a real 
molecular system, you're going to have LJ and/or bonded terms, and how 
well the codes compute them *together with the Coulomb terms* is what 
you really want to measure. It's like measuring how long a top chef 
takes to prepare a meal, and then wondering how they manage to feed a 
whole restaurant on time. They do lots of time-slicing and get lots of 
efficiencies of scale that are not available if you're doing just one meal.

> It seems, the energy value was calculated but the result was  zero
> because the sigma and epsilon were zero. In that case, the time

...or that the LJ component of the energy is always present even if 
there are no interactions to compute for it, which I expect is the case.

> reported by the program will also include the time of the extra
> calculation (unless the program is smart enough to know before hand
> that the result is going to be zero and return from the top!).

IIRC neighbour searching detects there's no LJ and so doesn't trigger 
loops that compute LJ.

> So,
> while comparing with other molecular dynamic packages, its not fair to
> report that time for gromacs which also includes non GB time (as that
> can make Gromacs slower than others who do not include non GB-time).
>
> Any suggestions about this? What is the fair approach for gromacs?

Look at the flop break-down to see if GROMACS thinks it is computing LJ 
any more. Or do some real timing measurements and compare before and after.

Mark

>
>
> Thanks,
> Jesmin
>
> On Fri, Aug 17, 2012 at 12:00 AM, Mark Abraham 
> <Mark.Abraham at anu.edu.au> wrote:
> > On 17/08/2012 1:14 PM, jesmin jahan wrote:
> >>
> >> Hi Mark,
> >>
> >> According to your advice "  remove the  the bonded terms and zero the
> >> VDW parameters",
> >> I removed everything under [ bond] , [angles], [pairs] and [ dihedrals
> >> ],
> >
> >
> > This only removes the "bonded" terms (in the sense of those atoms that
> > interact because of the presence of bonds). The VDW parameters for
> > non-bonded interactions are in ffnonbonded.itp for your force field. You
> > should probably follow the advice here
> > 
> http://www.gromacs.org/Documentation/How-tos/Adding_a_Residue_to_a_Force_Field#Modifying_a_force_field
> > to get a local copy you can change conveniently.
> >
> >
> >>   and run the simulation mdrun rerun.
> >>
> >> I  got output something like the following:
> >>
> >>
> >>     Energies (kJ/mol)
> >> GB Polarization        LJ (SR)   Coulomb (SR) Potential    Kinetic
> >> En.
> >>     -2.23121e+03    7.54287e+07   -3.47729e+04 7.53917e+07
> >> 0.00000e+00
> >>     Total Energy    Temperature Pressure (bar)
> >>      7.53917e+07    0.00000e+00    0.00000e+00
> >>
> >> where the previous output was something like this:
> >>
> >> Energies (kJ/mol)
> >>             Bond          Angle    Proper Dih. Improper Dih.GB
> >> Polarization
> >>      2.12480e+03    4.80088e+02    1.06648e+03 9.04861e+01
> >> -2.23122e+03
> >>            LJ-14     Coulomb-14        LJ (SR) Coulomb (SR)
> >> Potential
> >>      7.05695e+02    5.47366e+03   -4.16856e+02 -8.74797e+03
> >> -1.45483e+03
> >>      Kinetic En.   Total Energy    Temperature Pressure (bar)
> >>      0.00000e+00   -1.45483e+03    0.00000e+00 0.00000e+00
> >>
> >>
> >>
> >>     Energies (kJ/mol)
> >> GB Polarization        LJ (SR)   Coulomb (SR) Potential    Kinetic
> >> En.
> >>     -2.23121e+03    4.17621e+13   -3.47729e+04 4.17621e+13
> >> 0.00000e+00
> >>     Total Energy    Temperature Pressure (bar)
> >>      4.17621e+13    0.00000e+00    0.00000e+00
> >>
> >>
> >> So, you can see, although it has managed to remove some extra terms,
> >> the LJ and Columb potential are still there. I searched for VWD
> >> parameters. Although I saw various options for VWD, its not clear
> >> from the options, how to turn it off. Could you kindly tell me more
> >> clearly about it?
> >>
> >>
> >> I was also looking into the forcefield.itp file. I set the gen-pairs
> >> to no , fudgeLJ 1 and fudgeQQ to 1 which were yes, .5 and .83
> >> respectively originally.
> >>
> >> [ defaults ]
> >> ; nbfunc        comb-rule       gen-pairs       fudgeLJ fudgeQQ
> >> 1               2              no             1     1
> >>
> >> Please let me know how to get rid of calculation of other energies
> >> (LJ, Culumb and Total Potential) and how to set the parameters for
> >> this properly.
> >
> >
> > You can't get rid of the total. It's the total. You're trying to 
> keep the
> > (GB) Coulomb.
> >
> > Mark
> >
> >
> >>
> >> Thanks for your help.
> >>
> >> Sincerely,
> >> Jesmin
> >> On Thu, Aug 16, 2012 at 3:27 AM, Mark Abraham <Mark.Abraham at anu.edu.au>
> >> wrote:
> >>>
> >>> On 16/08/2012 5:08 PM, jesmin jahan wrote:
> >>>>
> >>>> Hi Mark,
> >>>>
> >>>> Thanks for your reply.
> >>>> If I open the .tpr file using notepad, it seems to be a binary file.
> >>>> Then, how to remove the  the bonded terms and zero the VDW 
> parameters?
> >>>
> >>>
> >>> In the .top file from which you made the .tpr. (And contributing .itp
> >>> files)
> >>> Parts of chapter 5 may help with this process.
> >>>
> >>> Mark
> >>>
> >>>
> >>>> I really need to compare how fast different well known package can
> >>>> compute GB-polarization energy and how good the energy values are?
> >>>> That's why time is an important factor me my experiments and I  
> really
> >>>> want to measure the time for GB energy in isolation !
> >>>>
> >>>> Thanks,
> >>>> Jesmin
> >>>>>
> >>>>> On Thu, Aug 16, 2012 at 2:44 AM, Mark Abraham 
> <Mark.Abraham at anu.edu.au>
> >>>>> wrote:
> >>>>>>
> >>>>>> On 16/08/2012 4:26 PM, jesmin jahan wrote:
> >>>>>>>
> >>>>>>> Hi Mark,
> >>>>>>>
> >>>>>>> Thanks for your previous reply.
> >>>>>>> I tried to run single point energy simulation with some proteins.
> >>>>>>> I got .log files with content like this:
> >>>>>>>
> >>>>>>> Energies (kJ/mol)
> >>>>>>>               Bond Angle    Proper Dih.  Improper Dih.GB
> >>>>>>> Polarization
> >>>>>>>        1.54109e+04 3.84351e+03    8.47152e+03    3.58425e+02
> >>>>>>> -1.69666e+04
> >>>>>>>              LJ-14 Coulomb-14        LJ (SR)   Coulomb (SR)
> >>>>>>> Potential
> >>>>>>>        4.29664e+03 3.63997e+04    2.22900e+05   -5.18818e+04
> >>>>>>> 2.22832e+05
> >>>>>>>        Kinetic En.   Total Energy    Temperature Pressure (bar)
> >>>>>>>        1.08443e+09 1.08465e+09    2.73602e+07    0.00000e+00
> >>>>>>> .......
> >>>>>>>
> >>>>>>> Computing:                               M-Number M-Flops  %
> >>>>>>> Flops
> >>>>>>>
> >>>>>>>
> >>>>>>> 
> -----------------------------------------------------------------------------
> >>>>>>>     Generalized Born Coulomb                 
> 0.005711           0.274
> >>>>>>> 0.2
> >>>>>>>     GB Coulomb + LJ                          0.416308          
> 25.395
> >>>>>>> 18.5
> >>>>>>>     Outer nonbonded loop                     
> 0.016367           0.164
> >>>>>>> 0.1
> >>>>>>>     1,4 nonbonded interactions               
> 0.008410           0.757
> >>>>>>> 0.6
> >>>>>>>     Born radii (HCT/OBC)                     0.439486          
> 80.426
> >>>>>>> 58.5
> >>>>>>>     Born force chain rule                    
> 0.439486           6.592
> >>>>>>> 4.8
> >>>>>>> NS-Pairs                                 0.943653 19.817
> >>>>>>> 14.4
> >>>>>>>     Reset In Box                             
> 0.003179           0.010
> >>>>>>> 0.0
> >>>>>>> CG-CoM                                   0.006358 0.019
> >>>>>>> 0.0
> >>>>>>> Bonds                                    0.003219 0.190
> >>>>>>> 0.1
> >>>>>>> Angles                                   0.005838 0.981
> >>>>>>> 0.7
> >>>>>>> Propers                                  0.011273 2.582
> >>>>>>> 1.9
> >>>>>>> Virial                                   0.003899 0.070
> >>>>>>> 0.1
> >>>>>>> Stop-CM                                  0.003179 0.032
> >>>>>>> 0.0
> >>>>>>> Calc-Ekin                                0.006358 0.172
> >>>>>>> 0.1
> >>>>>>>
> >>>>>>>
> >>>>>>> 
> -----------------------------------------------------------------------------
> >>>>>>> Total 137.479
> >>>>>>> 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 6859.0
> >>>>>>>
> >>>>>>>
> >>>>>>>         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        0.043        0.0
> >>>>>>> 1.4
> >>>>>>>     Comm. coord. 16          1        0.003        0.0
> >>>>>>> 0.1
> >>>>>>>     Neighbor search 16          1        0.103        0.0
> >>>>>>> 3.5
> >>>>>>>     Force 16          1        1.530        0.5
> >>>>>>> 51.5
> >>>>>>>     Wait + Comm. F 16          1        0.264        0.1
> >>>>>>> 8.9
> >>>>>>>     Write traj. 16          1        0.062        0.0
> >>>>>>> 2.1
> >>>>>>>     Update 16          1        0.001        0.0
> >>>>>>> 0.0
> >>>>>>>     Comm. energies 16          2        0.933        0.3
> >>>>>>> 31.4
> >>>>>>>     Rest 16                   0.031        0.0
> >>>>>>> 1.1
> >>>>>>>
> >>>>>>> 
> -----------------------------------------------------------------------
> >>>>>>>     Total 16                   2.970        0.9
> >>>>>>> 100.0
> >>>>>>>
> >>>>>>> 
> -----------------------------------------------------------------------
> >>>>>>>
> >>>>>>> NOTE: 31 % 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:      0.056 0.056    100.0
> >>>>>>>                   (Mnbf/s) (GFlops)   (ns/day)  (hour/ns)
> >>>>>>> Performance:      7.497 2.442      1.535     15.637
> >>>>>>>
> >>>>>>>
> >>>>>>> >From the log file, it seems, the time includes the time for 
> LJ and
> >>>>>>> Columb Potential Energy. But as I said before, I am only 
> interested
> >>>>>>> to
> >>>>>>> GB-energy times. I am doing a comparative study of GB-energy
> >>>>>>> performance (values vs time) for different molecular dynamic
> >>>>>>> packages.
> >>>>>>
> >>>>>>
> >>>>>> Since the LJ calculation also needs the distances, GROMACS does 
> them
> >>>>>> in
> >>>>>> the same loops and makes no apology for being efficient. :-) If 
> you're
> >>>>>> really trying to measure the time for the GB energy in 
> isolation, then
> >>>>>> you
> >>>>>> will need to construct a different model physics that lacks LJ
> >>>>>> interactions.
> >>>>>> Or perhaps you don't really want to measure the time for GB 
> energy in
> >>>>>> isolation. Depends what you're planning on using the 
> information for,
> >>>>>> but
> >>>>>> usually measuring a time representative of the calculation you 
> plan to
> >>>>>> run
> >>>>>> later is a good way to avoid having to account for lots of 
> subtleties
> >>>>>> of
> >>>>>> different packages.
> >>>>>>
> >>>>>>
> >>>>>>> That's why I was trying to deduct the time for any other extra 
> energy
> >>>>>>> computation time from it.
> >>>>>>>
> >>>>>>> Can anyone tell me how to get the exact time of GB-polarization
> >>>>>>> energy
> >>>>>>> (including Born radii) and excluding the times for any other
> >>>>>>> additional energy (like LJ and Columb etc) from gromacs 
> simutation?
> >>>>>>
> >>>>>>
> >>>>>> The .tpr you use for the rerun doesn't have to be one that will
> >>>>>> produce
> >>>>>> a sensible model physics. If you remove the bonded terms and 
> zero the
> >>>>>> VDW
> >>>>>> parameters then the only thing left to compute is the 
> electrostatics,
> >>>>>> which
> >>>>>> will give you the time you seek. You'll still potentially have time
> >>>>>> spent
> >>>>>> doing neighbour searching, and that is something you need to 
> consider
> >>>>>> for
> >>>>>> gauging relative performance of different packages. Again, the 
> times
> >>>>>> you
> >>>>>> measure will not be significant unless you run for at least several
> >>>>>> minutes.
> >>>>>>
> >>>>>> Mark
> >>>>>>
> >>>>>>
> >>>>>>> Thanks,
> >>>>>>> Jesmin
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> On Tue, Aug 14, 2012 at 10:16 AM, jesmin jahan 
> <shraban03 at gmail.com>
> >>>>>>> wrote:
> >>>>>>>>
> >>>>>>>> Thanks Mark for your reply. I was trying to use Single-Point 
> Energy
> >>>>>>>> Calculation as you advised in your first reply but for most 
> of the
> >>>>>>>> files the simulation failed because I was using the original .pdb
> >>>>>>>> files in the mdrun command.
> >>>>>>>>
> >>>>>>>> Anyways. I really appreciate your help.
> >>>>>>>> Thanks again,
> >>>>>>>> Jesmin
> >>>>>>>>
> >>>>>>>> On Tue, Aug 14, 2012 at 1:26 AM, Mark Abraham
> >>>>>>>> <Mark.Abraham at anu.edu.au> wrote:
> >>>>>>>>>
> >>>>>>>>> On 14/08/2012 7:38 AM, jesmin jahan wrote:
> >>>>>>>>>>
> >>>>>>>>>> Dear Gromacs Users,
> >>>>>>>>>>
> >>>>>>>>>> I have some questions regarding GB-Polarization Energy 
> Calculation
> >>>>>>>>>> with Gromacs. I will be grateful if someone can help me 
> with the
> >>>>>>>>>> answers.
> >>>>>>>>>>
> >>>>>>>>>> I am trying to calculate GB-Polarization energy for different
> >>>>>>>>>> Protein
> >>>>>>>>>> molecules. I am interested both in energy values with the time
> >>>>>>>>>> required to calculate the Born Radii and Polarization Energy.
> >>>>>>>>>> I am not doing any energy minimization step as the files I am
> >>>>>>>>>> using
> >>>>>>>>>> as
> >>>>>>>>>> input are already minimized.
> >>>>>>>>>>
> >>>>>>>>>> Here is the content of my  mdrun.mdp file:
> >>>>>>>>>>
> >>>>>>>>>> constraints         = none
> >>>>>>>>>> integrator =  md
> >>>>>>>>>> pbc                       =  no
> >>>>>>>>>> dt                         =  0.001
> >>>>>>>>>> nsteps =  0
> >>>>>>>>>> implicit_solvent    = GBSA
> >>>>>>>>>> gb_algorithm        = HCT
> >>>>>>>>>> sa_algorithm        = None
> >>>>>>>>>>
> >>>>>>>>>> And I am using following three steps for all the .pdb files I
> >>>>>>>>>> have:
> >>>>>>>>>>
> >>>>>>>>>> let x is the name of the .pdb file.
> >>>>>>>>>>
> >>>>>>>>>> pdb2gmx -f x.pdb -ter -ignh -ff amber99sb -water none
> >>>>>>>>>> grompp -f mdr.mdp -c conf.gro -p topol.top -o imd.tpr
> >>>>>>>>>> mpirun -np 8 mdrun_mpi -deffnm imd -v -g x.log
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> So you're not using the advice I gave you about how to calculate
> >>>>>>>>> single
> >>>>>>>>> point energies. OK.
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>> 1 .Now the running time reported by a log file also 
> includes other
> >>>>>>>>>> times. Its also not clear to me whether the time includes 
> the time
> >>>>>>>>>> for
> >>>>>>>>>> Born Radii calculations.
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> The timing breakdown is printed at the end of the .log file. 
> Likely
> >>>>>>>>> your
> >>>>>>>>> time is heavily dominated by the GB calculation and 
> communication
> >>>>>>>>> cost. Born
> >>>>>>>>> radii calculation are part of the former, and not reported
> >>>>>>>>> separately. You
> >>>>>>>>> should not bother with timing measurements unless your run 
> goes for
> >>>>>>>>> at least
> >>>>>>>>> several minutes, else your time will be dominated by I/O and 
> setup
> >>>>>>>>> costs.
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>> So, to get the GB-energy time  I am doing the following: I 
> am also
> >>>>>>>>>> running a simulation with "implicit_solvent" set to "no" 
> and I am
> >>>>>>>>>> taking the difference of these two (with GB and Without GB). Is
> >>>>>>>>>> that
> >>>>>>>>>> a
> >>>>>>>>>> right approach?
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> No, that measures the weight difference between an apple and an
> >>>>>>>>> orange, not
> >>>>>>>>> whether the apple's seeds are heavy.
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>> I also want to be sure that it also includes Born-Radii
> >>>>>>>>>> calculation
> >>>>>>>>>> time.
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> It's part of the GB calculation, so it's included in its timing.
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>> Is there any other approach to do this?
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> 2. I was trying to run the simulations on 192 cores (16 
> nodes each
> >>>>>>>>>> with 12 codes). But I got "There is no domain decomposition 
> for 12
> >>>>>>>>>> nodes that is compatible with the given box and a minimum cell
> >>>>>>>>>> size
> >>>>>>>>>> of
> >>>>>>>>>> 2.90226 nm" error for some pdb files. Can anyone explain 
> what is
> >>>>>>>>>> happening. Is there any restriction on number of nodes can be
> >>>>>>>>>> used?
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> Yes. See discussion linked from
> >>>>>>>>> http://www.gromacs.org/Documentation/Errors
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>> 3. I run the simulations with 1 way 96 (8 nodes each with 12
> >>>>>>>>>> cores).
> >>>>>>>>>> Its not clear to me from the log file whether Gromacs is 
> able to
> >>>>>>>>>> utilize all the 92 cores. It seems, it is using only 8 nodes.
> >>>>>>>>>> Does Gromacs use both shared and distributed memory 
> parallelism?
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> Not at the moment. Look at the top of your .log file for clues
> >>>>>>>>> about
> >>>>>>>>> what
> >>>>>>>>> your configuration is making available to GROMACS. It is likely
> >>>>>>>>> that
> >>>>>>>>> mpirun
> >>>>>>>>> -np 8 makes only 8 MPI processes available to GROMACS. Using 
> more
> >>>>>>>>> will
> >>>>>>>>> require you to use your MPI installation correctly (and we can't
> >>>>>>>>> help
> >>>>>>>>> with
> >>>>>>>>> that).
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>> 4.   In the single-point energy  calculation "mdrun -s 
> input.tpr
> >>>>>>>>>> -rerun configuration.pdb", is the configuration.pdb 
> mentioned  is
> >>>>>>>>>> the
> >>>>>>>>>> original pdb file used on pdb2gmx  with -f option? Or its a
> >>>>>>>>>> modified
> >>>>>>>>>> pdb file? I am asking because if I use the original file 
> that does
> >>>>>>>>>> not
> >>>>>>>>>> work always :-(
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> It can be any configuration that matches the .top file you 
> gave to
> >>>>>>>>> grompp.
> >>>>>>>>> That's the point - you only need one run input file to 
> compute the
> >>>>>>>>> energy of
> >>>>>>>>> any such configuration you later want. The configuration you 
> gave
> >>>>>>>>> to
> >>>>>>>>> grompp
> >>>>>>>>> (or any other tool) doesn't matter.
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>> 5. Is there any known speedup factor of Gromacs on multicores?
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> That depends on your simulation system, hardware, network and
> >>>>>>>>> algorithm.
> >>>>>>>>> Don't bother with fewer than hundreds of atoms per core.
> >>>>>>>>>
> >>>>>>>>> Mark
> >>>>>>>>> --
> >>>>>>>>> gmx-users mailing list gmx-users at gromacs.org
> >>>>>>>>> http://lists.gromacs.org/mailman/listinfo/gmx-users
> >>>>>>>>> * Only plain text messages are allowed!
> >>>>>>>>> * Please search the archive at
> >>>>>>>>> http://www.gromacs.org/Support/Mailing_Lists/Search before 
> posting!
> >>>>>>>>> * Please don't post (un)subscribe requests to the list. Use 
> the www
> >>>>>>>>> interface or send it to gmx-users-request at gromacs.org.
> >>>>>>>>> * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> --
> >>>>>>>> Jesmin Jahan Tithi
> >>>>>>>> PhD Student, CS
> >>>>>>>> Stony Brook University, NY-11790.
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>> --
> >>>>>> gmx-users mailing list gmx-users at gromacs.org
> >>>>>> http://lists.gromacs.org/mailman/listinfo/gmx-users
> >>>>>> * Only plain text messages are allowed!
> >>>>>> * Please search the archive at
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> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> --
> >>>>> Jesmin Jahan Tithi
> >>>>> PhD Student, CS
> >>>>> Stony Brook University, NY-11790.
> >>>>>
> >>>>
> >>>> --
> >>>> Jesmin Jahan Tithi
> >>>> PhD Student, CS
> >>>> Stony Brook University, NY-11790.
> >>>
> >>>
> >>> --
> >>> gmx-users mailing list    gmx-users at gromacs.org
> >>> http://lists.gromacs.org/mailman/listinfo/gmx-users
> >>> * Only plain text messages are allowed!
> >>> * Please search the archive at
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> >>
> >>
> >>
> >
> > --
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>
>
>
> -- 
> Jesmin Jahan Tithi
> PhD Student, CS
> Stony Brook University, NY-11790.
> -- 
> gmx-users mailing list    gmx-users at gromacs.org
> http://lists.gromacs.org/mailman/listinfo/gmx-users
> * Only plain text messages are allowed!
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> http://www.gromacs.org/Support/Mailing_Lists/Search before posting!
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