[gmx-developers] [Fwd: coulomb SR in 3.3cvs]

David spoel at xray.bmc.uu.se
Mon Jul 18 19:32:41 CEST 2005


On Mon, 2005-07-18 at 17:31 +0200, Michel Cuendet wrote:
> Hi David,
> 
> No, there is no LJ-LR when runnnig g_energy. (?)
> 
> I'm using parrinello-rahman pressure coupling. But it seems to me that 
> there is no significant difference related to that :
Is this from the same tpr? How can the density be different?

Did you check this:
http://www.gromacs.org/features/changes33.html


> 
> 3.2.1 :
> 
> ----------------------------------------------------------------
> 
> Volume                      887.289    1.27296    1.25576 -0.0555579  -0.722363
> pV                         -187.347    5068.08    5066.15      37.24    484.195
> Pressure (bar)             -3.46691    94.8199    94.7838   0.697585       9.07
> Density (SI)                1005.13    1.44124    1.42162  0.0631539   0.821127
> 
> 3.3
> ----------------------------------------------------------------
> Volume                      887.104    1.40517    1.39327  0.0596162   0.632051
> pV                          11.4915    5133.23    5129.17    66.7174    707.338
> Pressure (bar)             0.282085    96.0735    95.9974    1.24973    13.2496
> Density (SI)                1005.34    1.59044    1.57699 -0.0674518  -0.715124
> 
> 
> Thanks for your assitsance !
> 
> Bye,
> 
> Michel
> 
> Below is my mdp file :
> 
> 
> constraints         =  hbonds
> 
> integrator          =  md
> 
> dt                  =  0.002    ; ps !
> 
> nsteps              =  2000000  ; total 4.0 ns.
> 
> nstcomm             =  1
> 
> nstxout             =  20000
> 
> nstvout             =  100000
> 
> nstfout             =  0
> 
> nstlog              =  1000
> 
> nstenergy           =  10
> 
> nstxtcout           =  10
> 
> xtc_grps            =  System
> 
> nstlist             =  10
> 
> ns_type             =  grid
> 
> coulombtype         =  PME
> 
> rlist               =  1.0
> 
> rcoulomb            =  1.0
> 
> vdwtype             = shift
> 
> rvdw_switch         =  0.9
> 
> rvdw                =  1.0
> 
> Tcoupl              =  nose-hoover
> 
> tc-grps             =  Protein  Other
> 
> tau_t               =  0.1      0.1
> 
> ref_t               =  300      300
> 
> energygrps          =  T MHC_a12_Tax
> 
> Pcoupl              =  parrinello-rahman
> 
> Pcoupltype          =  isotropic
> 
> tau_p               =  1.0
> 
> compressibility     =  4.5e-5
> 
> ref_p               =  1.0
> 
> 
> 
> David van der Spoel wrote:
> 
> >On Mon, 18 Jul 2005, Michel Cuendet wrote:
> >
> >  
> >
> >>Hi,
> >>
> >>I subitted this message already on the gmx-users mailing list, but got no
> >>feedback. I think it's an important issue for the CVS version 3.3. In the
> >>meantime, I could reproduce the problem on xeon cpus, so it's not itanium specific.
> >>    
> >>
> >
> >Are these all the energies? No LJ-LR?
> >Are you running pressure coupling? If so check differences there as well.
> >
> >Do also check the revisions page.
> >
> >  
> >
> >>Here is the original message :
> >>--------------------------------------------------------------------------------
> >>
> >>I compiled the 3.3 CVS version of 27.05.2005 on itanium2 with the intel
> >>8.1 compiler. (for those who don't know, the cvs version brings a
> >>terrific speedup on itaniums). Tests were performed with both versions
> >>in double precision.
> >>
> >>I compared the different energies obtained with 3.2.1 and 3.3, by taking
> >>the same trr (from a 3.2.1 equilibration, 85000 atoms, PME) and running
> >>it with both versions for about 12ps. From the tables below, one sees
> >>that there is a gap between Coulomb (SR) of 3450 KJ/mol, and between
> >>potential energies of  3280 KJ/mol.
> >>
> >>A close inspection of the energy files reveals that the version 3.3
> >>reproduces the same energy as 3.2.1 at the first step, but the system
> >>relaxes very quickly (0.5ps) to a lower energy with 3.3.
> >>
> >>Rerunning with 3.3 the trajectory produced by 3.2.1 surprisingly gives
> >>the correct energies.
> >>
> >>Any explaination for that ?
> >>
> >>Thanks,
> >>Michel
> >>
> >>
> >>3.2.1 :
> >>
> >>Energy                      Average       RMSD     Fluct.      Drift  Tot-Drift
> >>
> >>-------------------------------------------------------------------------------
> >>
> >>G96Bond                      6723.8    140.873    138.612   -6.69756   -87.0817
> >>
> >>G96Angle                    10213.6    173.746    173.579    2.02771    26.3642
> >>
> >>Proper Dih.                 4446.16    89.4129    84.2042    8.01199    104.172
> >>
> >>Improper Dih.               3264.55     78.886    78.3318   -2.48685    -32.334
> >>
> >>LJ-14                       852.608     79.621      79.52     1.0681    13.8874
> >>
> >>Coulomb-14                  62903.9    126.041    122.079   -8.35397   -108.618
> >>
> >>LJ (SR)                      166906    1099.22     1099.1   -4.19132   -54.4955
> >>
> >>Coulomb (SR)             -1.2043e+06    1629.38    1629.34    -3.3074   -43.0028
> >>
> >>Coulomb (LR)                -188686     91.952    90.6651    4.08445     53.106
> >>
> >>Potential                -1.13768e+06    1031.78    1031.12   -9.84429   -127.995
> >>
> >>3.3 CVS
> >>
> >>Energy                      Average       RMSD     Fluct.      Drift  Tot-Drift
> >>
> >>-------------------------------------------------------------------------------
> >>
> >>G96Bond                     6486.57    122.559    120.492   -7.32269   -77.6351
> >>
> >>G96Angle                    10003.9    152.062    152.054  -0.496268   -5.26144
> >>
> >>Proper Dih.                 4391.87    83.2508    80.8574    6.47554    68.6537
> >>
> >>Improper Dih.               3194.22    78.6896    78.6495   0.819815    8.69168
> >>
> >>LJ-14                       833.553    76.0076    75.8776   -1.45206   -15.3947
> >>
> >>Coulomb-14                    62899    124.539     123.82   -4.36711   -46.3001
> >>
> >>LJ (SR)                      167720    1182.33    1157.55    78.6782    834.146
> >>
> >>Coulomb (SR)             -1.20775e+06    1897.76    1850.85   -137.014   -1452.62
> >>
> >>Coul. recip.                -188746     100.09    100.079    0.48938    5.18841
> >>
> >>Potential                -1.14096e+06    1149.25    1132.33   -64.1897   -680.539
> >>
> >>
> >>
> >>    
> >>
> >
> >  
> >
> 
-- 
David.
________________________________________________________________________
David van der Spoel, PhD, Assoc. Prof., Molecular Biophysics group,
Dept. of Cell and Molecular Biology, Uppsala University.
Husargatan 3, Box 596,          75124 Uppsala, Sweden
phone:  46 18 471 4205          fax: 46 18 511 755
spoel at xray.bmc.uu.se    spoel at gromacs.org   http://xray.bmc.uu.se/~spoel
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