[gmx-users] Re:What does this message mean?

Mark Abraham Mark.Abraham at anu.edu.au
Wed Jun 6 07:37:35 CEST 2012


On 6/06/2012 12:26 AM, Bao Kai wrote:
> Hi, Mark,
>
> Following please find the information.
>
> pure_water]$ g_energy_d -f step11.edr
>                           :-)  G  R  O  M  A  C  S  (-:
>
>                        GROwing Monsters And Cloning Shrimps
>
>                              :-)  VERSION 4.5.5  (-:
>
>          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.
>
>                      :-)  g_energy_d (double precision)  (-:
>
> Option     Filename  Type         Description
> ------------------------------------------------------------
>    -f     step11.edr  Input        Energy file
>   -f2       ener.edr  Input, Opt.  Energy file
>    -s      topol.tpr  Input, Opt.  Run input file: tpr tpb tpa
>    -o     energy.xvg  Output       xvgr/xmgr file
> -viol  violaver.xvg  Output, Opt. xvgr/xmgr file
> -pairs    pairs.xvg  Output, Opt. xvgr/xmgr file
> -ora    orienta.xvg  Output, Opt. xvgr/xmgr file
> -ort    orientt.xvg  Output, Opt. xvgr/xmgr file
> -oda    orideva.xvg  Output, Opt. xvgr/xmgr file
> -odr    oridevr.xvg  Output, Opt. xvgr/xmgr file
> -odt    oridevt.xvg  Output, Opt. xvgr/xmgr file
> -oten    oriten.xvg  Output, Opt. xvgr/xmgr file
> -corr   enecorr.xvg  Output, Opt. xvgr/xmgr file
> -vis      visco.xvg  Output, Opt. xvgr/xmgr file
> -ravg  runavgdf.xvg  Output, Opt. xvgr/xmgr file
> -odh       dhdl.xvg  Output, Opt. xvgr/xmgr file
>
> Option       Type   Value   Description
> ------------------------------------------------------
> -[no]h       bool   no      Print help info and quit
> -[no]version bool   no      Print version info and quit
> -nice        int    19      Set the nicelevel
> -b           time   0       First frame (ps) to read from trajectory
> -e           time   0       Last frame (ps) to read from trajectory
> -[no]w       bool   no      View output .xvg, .xpm, .eps and .pdb files
> -xvg         enum   xmgrace  xvg plot formatting: xmgrace, xmgr or none
> -[no]fee     bool   no      Do a free energy estimate
> -fetemp      real   300     Reference temperature for free energy calculation
> -zero        real   0       Subtract a zero-point energy
> -[no]sum     bool   no      Sum the energy terms selected rather than display
>                              them all
> -[no]dp      bool   no      Print energies in high precision
> -nbmin       int    5       Minimum number of blocks for error estimate
> -nbmax       int    5       Maximum number of blocks for error estimate
> -[no]mutot   bool   no      Compute the total dipole moment from the
>                              components
> -skip        int    0       Skip number of frames between data points
> -[no]aver    bool   no      Also print the exact average and rmsd stored in
>                              the energy frames (only when 1 term is requested)
> -nmol        int    1       Number of molecules in your sample: the energies
>                              are divided by this number
> -[no]driftcorr bool no      Useful only for calculations of fluctuation
>                              properties. The drift in the observables will be
>                              subtracted before computing the fluctuation
>                              properties.
> -[no]fluc    bool   no      Calculate autocorrelation of energy fluctuations
>                              rather than energy itself
> -[no]orinst  bool   no      Analyse instantaneous orientation data
> -[no]ovec    bool   no      Also plot the eigenvectors with -oten
> -acflen      int    -1      Length of the ACF, default is half the number of
>                              frames
> -[no]normalize bool yes     Normalize ACF
> -P           enum   0       Order of Legendre polynomial for ACF (0 indicates
>                              none): 0, 1, 2 or 3
> -fitfn       enum   none    Fit function: none, exp, aexp, exp_exp, vac,
>                              exp5, exp7, exp9 or erffit
> -ncskip      int    0       Skip N points in the output file of correlation
>                              functions
> -beginfit    real   0       Time where to begin the exponential fit of the
>                              correlation function
> -endfit      real   -1      Time where to end the exponential fit of the
>                              correlation function, -1 is until the end
>
> Opened step11.edr as double precision energy file
>
> Select the terms you want from the following list by
> selecting either (part of) the name or the number or a combination.
> End your selection with an empty line or a zero.
> -------------------------------------------------------------------
>    1  LJ-(SR)          2  Disper.-corr.    3  Coulomb-(SR)     4  Coul.-recip.
>    5  Potential        6  Kinetic-En.      7  Total-Energy     8  Temperature
>    9  Pres.-DC        10  Pressure        11  Box-X           12  Box-Y
>   13  Box-Z           14  Volume          15  Density         16  pV
>   17  Enthalpy        18  Vir-XX          19  Vir-XY          20  Vir-XZ
>   21  Vir-YX          22  Vir-YY          23  Vir-YZ          24  Vir-ZX
>   25  Vir-ZY          26  Vir-ZZ          27  Pres-XX         28  Pres-XY
>   29  Pres-XZ         30  Pres-YX         31  Pres-YY         32  Pres-YZ
>   33  Pres-ZX         34  Pres-ZY         35  Pres-ZZ         36  #Surf*SurfTen
>   37  Box-Vel-XX      38  Box-Vel-YY      39  Box-Vel-ZZ      40  Mu-X
>   41  Mu-Y            42  Mu-Z            43  T-System        44  Lamb-System
>
> 10
> 15
> 8
>
>
> Back Off! I just backed up energy.xvg to ./#energy.xvg.3#
> Last energy frame read 1000 time 1000.000
>
> Statistics over 1000001 steps [ 0.0000 through 1000.0000 ps ], 3 data sets
> All statistics are over 200001 points
>
> Energy                      Average   Err.Est.       RMSD  Tot-Drift
> -------------------------------------------------------------------------------
> Temperature                 317.954      0.055    5.75871   0.187709  (K)
> Pressure                    100.523       0.21    406.025  0.0312674  (bar)
> Density                     967.417       0.16     8.5886   0.992783  (kg/m^3)
>
> You may want to use the -driftcorr flag in order to correct
> for spurious drift in the graphs. Note that this is not
> a substitute for proper equilibration and sampling!
>
> WARNING: nmol = 1, this may not be what you want.
>
> Temperature dependent fluctuation properties at T = 317.954.
>
> Heat capacities obtained from fluctuations do *not* include
> quantum corrections. If you want to get a more accurate estimate
> please use the g_dos program.
>
> WARNING: Please verify that your simulations are converged and perform
> a block-averaging error analysis (not implemented in g_energy yet)
>
> ++++ PLEASE READ AND CITE THE FOLLOWING REFERENCE ++++
> M. P. Allen and D. J. Tildesley
> Computer simulation of liquids
> Oxford Science Publications 1 (1987) pp. 1
> -------- -------- --- Thank You --- -------- --------
>
>
> gcq#74: "Baseball Heroes Only" (P.J. Harvey)
>
> Thank you.
> Kai
>
>
> On 5/06/2012 10:51 PM, Bao Kai wrote:
>> Hi, all,
>>
>> It is very easy for me to get the following message.
>>
>> WARNING: nmol = 1, this may not be what you want.
>>
>> Temperature dependent fluctuation properties at T = 317.98.
>>
>> I am wondering if somebody can tell me what does it mean or if it is a
>> problem to improve?

Had you made different choices of output quantities, there would be more 
output from g_energy, and in that context the value of nmol is relevant. 
With your choices it doesn't matter, and I have opened a bug report to 
explore whether this output should not appear at all.

Thanks,

Mark



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