[gmx-users] Issues of NEMD + 1/viscosity from g_energy

shikha nangia nshikha at yahoo.com
Sat Apr 16 22:31:54 CEST 2011


Thanks again, Justin.

Dear all,

I figured out the problem. Error was in my mdp file options. I did not specify the acc-groups correctly. I can get 1/viscosity using g_energy.

However, once the acc-groups are specified, now the NEW issue is not being able to run my job correctly.

I get the following errors:

Step 376, time 7.52 (ps)  LINCS WARNING
relative constraint deviation after LINCS:
rms 0.006964, max 0.163855 (between atoms 861 and 859)
bonds that rotated more than 30 degrees:
 atom 1 atom 2  angle  previous, current, constraint length

----
-------


-------------------------------------------------------
Program mdrun, VERSION 4.5.4
Source code file: domdec.c, line: 4124

Fatal error:
A charge group moved too far between two domain decomposition steps

---------------

I did not have any problems in my equilibrium simulations...this is happening in NEMD simulations.

Here is my .mdp file

title                    = Martini
cpp                      = /usr/bin/cpp
integrator               = md
tinit                    = 0.0
dt                       = 0.01
nsteps                   = 500
nstcomm                  = 1
comm-grps                         = system
nstxout                  = 10
nstvout                  = 10
nstfout                  = 10
nstlog                   = 10
nstenergy                = 10
nstxtcout                = 2500
xtc_precision            = 100
xtc-grps                 = 
energygrps               = system
nstlist                  = 1
ns_type                  = grid
pbc                      = xyz
rlist                    = 1.7
coulombtype              = Shift 
rcoulomb_switch          = 0.0
rcoulomb                 = 1.2
epsilon_r                = 15
vdw_type                 = Shift 
rvdw_switch              = 0.9
rvdw                     = 1.2
DispCorr                 = EnerPres
tcoupl                   = V-rescale
tc-grps                  = NGL W
tau_t                    = 1.0 1.0 
ref_t                    = 300. 300.
Pcoupl                   = No
Pcoupltype               = Isotropic
tau_p                    = 1.0 
compressibility          = 1e-5
ref_p                    = 1.0 
gen_vel                  = Yes
gen_temp                 = 300
gen_seed                 = 473529
constraints              = None
constraint_algorithm     = Lincs
unconstrained_start      = no
lincs_order              = 1
lincs_warnangle          = 30

; Non-equilibrium MD stuff
acc-grps                 =  NGL W
accelerate               =  0.1 0 0 -0.1 0 0
freezegrps               =   
freezedim                =   
cos_acceleration         = 0.1 
deform                   =  

Best,
SN

--- On Sat, 4/16/11, Justin A. Lemkul <jalemkul at vt.edu> wrote:

From: Justin A. Lemkul <jalemkul at vt.edu>
Subject: Re: [gmx-users] 1/viscosity from g_energy
To: "Discussion list for GROMACS users" <gmx-users at gromacs.org>
Date: Saturday, April 16, 2011, 3:27 PM



shikha nangia wrote:
> Thanks for your instant reply, Justin.
> 
> Dear all,
> 
> Please correct me if I am woring here....but...reading through the user-list, I gathered that -vis option og g_energy oes not give good results and instead cos_accleration should be used from the following reference.
> 
>> /@Article{Hess2002b,
> />/   author =      {B. Hess},
> />/   title =      {Determining the shear viscosity of model liquids from />/molecular simulation},
> />/   journal =      {J. Chem. Phys.},
> />/   year =      2002,
> />/   volume =     116,
> />/   pages =     {209-217}
> />/}
> /
> 
> I am trying to get the results of viscosity through cos_acceleration that probably are formatted as below (taken from a user-list).
> 
>> / Energy                      Average   Err.Est.       RMSD 
>  Tot-Drift
> />/ -------------------------------------------------------------------------------
> />/ 1/Viscosity                                        / (/ s/kg)
> /
> 
> 

If the proper output options are not there, then there may have been a problem in the .mdp file that prevented the correct energy terms from being written.  If present in the .edr file, it should be shown in the list (sorry, I was thinking of something else).  Please post your .mdp file.

-Justin

> Thanks again,
> 
> SN
> 
> --- On *Sat, 4/16/11, Justin A. Lemkul /<jalemkul at vt.edu>/* wrote:
> 
> 
>     From: Justin A. Lemkul <jalemkul at vt.edu>
>     Subject: Re: [gmx-users] 1/viscosity from g_energy
>     To: "Discussion list for GROMACS users" <gmx-users at gromacs.org>
>     Date: Saturday, April 16, 2011, 3:06 PM
> 
> 
> 
>     shikha nangia wrote:
>      > Dear gmx-users,
>      >
>      > I am trying to obtain 1/viscosity values for my system after
>     using the cos_acceleration option in the mdp file. My gromacs
>     version is 4.5.4 released on March 21, 2011.
>      > When I try using the g_energy option for my file
>      >
>      > g_energy -f ener.edr -o outfile.xvg
>      >
>      > I get the following options
>      >
>      > End your selection with an empty line or a zero.
>      > -------------------------------------------------------------------
>      >   1  Bond             2  Angle            3  Improper-Dih.    4     LJ-(SR)        5  Disper.-corr.    6  Coulomb-(SR)     7  Potential           8  Kinetic-En.    9  Total-Energy    10  Conserved-En.   11     Temperature     12  Pres.-DC      13  Pressure        14  Box-XX             15  Box-YY          16  Box-ZZ        17  Box-YX          18     Box-ZX          19  Box-ZY          20  Volume        21  Density            22  pV              23  Enthalpy        24  Vir-XX        25     Vir-XY          26  Vir-XZ          27  Vir-YX          28  Vir-YY           29  Vir-YZ          30  Vir-ZX          31  Vir-ZY             32  Vir-ZZ        33  Pres-XX         34  Pres-XY         35     Pres-XZ         36  Pres-YX   
    37  Pres-YY         38  Pres-YZ            39  Pres-ZX         40  Pres-ZY       41  Pres-ZZ         42     #Surf*SurfTen   43  Mu-X            44  Mu-Y          45  Mu-Z               46  T-System        47  Lamb-System      >
>      > I am not sure which option (1 to 47) gives 1/viscosity. I tried
>     looking through the manual and searching the user list but could not
>     resolve the issue.
>      >
>      > Please let me know what am I missing here.
>      >
> 
>     Use -vis rather than -o.
> 
>     -Justin
> 
>      > Thanks,
>      > SN
>      >
>      >
> 
>     -- ========================================
> 
>     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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-- ========================================

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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