[gmx-users] Test Particle Insertion of Water

Javier Cerezo jcb1 at um.es
Wed May 9 16:16:06 CEST 2012


The trr file has something wrong. Look at "Coords", it has 0 frames

You may have forgotten to set nstxout to a non-zero value?

Javier

El 09/05/12 16:10, Steven Neumann escribió:
> I added one water molecule in my topology to all water molecules:
>
> [ molecules ]
> ; Compound        #mols
> Alanine            40
> SOL               724
>
> Maybe I should add aditional line like:
>
> [ molecules ]
> ; Compound        #mols
> Alanine            40
> SOL               723
> SOL                  1
>
> What do you think?
>
>
> On Wed, May 9, 2012 at 3:04 PM, Steven Neumann <s.neumann08 at gmail.com 
> <mailto:s.neumann08 at gmail.com>> wrote:
>
>     Checking file md.trr
>     trn version: GMX_trn_file (single precision)
>     Reading frame       0 time    0.000
>     # Atoms  2569
>     Last frame       2000 time 100000.000
>
>
>     Item        #frames Timestep (ps)
>     Step          2001    50
>     Time          2001    50
>     Lambda        2001    50
>     Coords           0
>     Velocities    2001    50
>     Forces           0
>     Box           2001    50
>
>     Well, it looks ok. Any suggestions?
>
>
>     On Wed, May 9, 2012 at 3:01 PM, Javier Cerezo <jcb1 at um.es
>     <mailto:jcb1 at um.es>> wrote:
>
>         Sorry, I saw now the command line you've posted. Did you check
>         your trr with gmxcheck?
>
>
>         El 09/05/12 15:49, Steven Neumann escribió:
>>         hello gmx users,
>>
>>
>>         I am sorry for bothering you but I was searching mailing list
>>         and no results. I have a problem with my test particle
>>         insertion as I run the workflow I described previously with
>>         my mdp:
>>
>>         title       = Test Particle Insertion
>>         ; Run parameters
>>         integrator  = tpi
>>         nsteps      = 50000000    ; 100 ns
>>         dt          = 0.002     ; 2 fs
>>         ; Output control
>>         nstxout     = 0          ; suppress .trr output ; output
>>         coordinates every 25 ps
>>         nstvout     = 25000     ; velocities to output every 25000 steps
>>         nstenergy   = 1000      ; save energies every 2 ps
>>         nstlog      = 1000      ; update log file every 2 ps
>>         nstxtcout   = 100000         ; suppress (tlumic) xtc trajectory
>>         energygrps  = System
>>         continuation    = no           ; first dynamics run
>>         constraint_algorithm = lincs    ; holonomic constraints
>>         constraints     = all-bonds     ; all bonds (even heavy
>>         atom-H bonds) constrained
>>         lincs_iter      = 1             ; accuracy of LINCS
>>         lincs_order     = 4             ; also related to accuracy
>>         ; Neighborsearching
>>         ns_type     = grid      ; search neighboring grid cells
>>         nstlist     = 5         ; 10 fs
>>         vdwtype     = Switch
>>         rvdw-switch = 1.0
>>         rlist       = 1.4       ; short-range neighborlist cutoff (in nm)
>>         rcoulomb    = 1.4       ; short-range electrostatic cutoff
>>         (in nm)
>>         rvdw        = 1.2       ; short-range van der Waals cutoff
>>         (in nm)
>>         ewald_rtol  = 1e-5      ; relative strenght of the
>>         Ewald-shifted potential rcoulomb
>>         ; Electrostatics
>>         coulombtype     = PME       ; Particle Mesh Ewald for
>>         long-range electrostatics
>>         pme_order       = 4         ; cubic interpolation
>>         fourierspacing  = 0.12      ; grid spacing for FFT
>>         ; Temperature coupling is on
>>         tcoupl      = V-rescale                     ; modified
>>         Berendsen thermostat
>>         tc_grps     = System                 ; two coupling groups -
>>         more accurate
>>         tau_t       = 0.1                             ; time
>>         constant, in ps
>>         ref_t       = 318                         ; reference
>>         temperature, one for each group, in K
>>         ; Pressure coupling is on
>>         pcoupl      = Parrinello-Rahman             ; pressure
>>         coupling is on for NPT
>>         pcoupltype  = isotropic                     ; uniform scaling
>>         of box vectors
>>         tau_p       = 2.0                           ; time constant,
>>         in ps
>>         ref_p       = 1.0                           ; reference
>>         pressure, in bar
>>         compressibility = 4.5e-5                    ; isothermal
>>         compressibility of water, bar^-1
>>         ; Periodic boundary conditions
>>         pbc         = xyz       ; 3-D PBC
>>         ; Dispersion correction
>>         DispCorr    = EnerPres  ; account for cut-off vdW scheme
>>         ; Velocity generation
>>         gen_vel     = yes       ; assign velocities from Maxwell
>>         distribution
>>         gen_temp    = 318       ; temperature for Maxwell distribution
>>         gen_seed    = -1        ; generate a random seed
>>
>>         Then My log file:
>>
>>
>>          The temperature for test particle insertion is 318.000 K
>>
>>         Started Test Particle Insertion on node 0 Wed May  9 14:18:18
>>         2012
>>
>>         Will insert 3 atoms with partial charges
>>
>>         Will insert 50000000 times in each frame of md318.trr
>>         Will use the same neighborlist for 5 insertions in a sphere
>>         of radius 0.050000
>>
>>         <V>  =         -nan nm^3
>>         <mu> =         -nan kJ/mol
>>         No MEGA Flopsen this time
>>
>>              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     %
>>         ------------------------------
>>         -----------------------------------------
>>          Rest                   4                   5.218       
>>         1.9   100.0
>>         -----------------------------------------------------------------------
>>          Total                  4                   5.218       
>>         1.9   100.0
>>         -----------------------------------------------------------------------
>>
>>             Parallel run - timing based on wallclock.
>>
>>                        NODE (s)   Real (s)      (%)
>>                Time:      0.485      0.485    100.0
>>                        (Mnbf/s)   (MFlops)   (steps/hour)
>>         Performance:      0.000      0.000            0.0
>>         Finished mdrun on node 0 Wed May  9 14:18:19 2012
>>
>>
>>
>>         Files are empty. Do you have any clue what is happening?
>>
>>         Thank you for your time,
>>
>>         Steven
>>
>>
>>         On Wed, May 9, 2012 at 1:45 PM, Javier Cerezo <jcb1 at um.es
>>         <mailto:jcb1 at um.es>> wrote:
>>
>>             Hi Steven
>>
>>             As I remember, TPI is based on the calculation of the
>>             potential at every conformation from the already computed
>>             simulation (inserting the particle in every snapshot), so
>>             velocities are not used.
>>
>>             Anyway, use both and see if there are any differences.
>>
>>             Javier
>>
>>             El 09/05/12 11:27, Steven Neumann escribió:
>>>             Dear Gmx Users,
>>>
>>>             I am running TPI of the water in the system containing
>>>             free amino acids. Steps:
>>>
>>>             1. I run the NPT simulation of 100 ns to equilibrate the
>>>             system.
>>>             2. I added 1 extra water molecule to the final pdb file
>>>             (converted from gro) and to topology
>>>             3. I creaded tpi.tpr using grompp using new pdb file
>>>             with extra water molecule
>>>             4. mdrun --s tpi298.tpr -rerun md298.trr -deffnm tpi298
>>>             -tpi tpi298.xvg -tpid tpid298.xvg
>>>
>>>             My question: Is it better generate new velocities in my
>>>             mdp file (continuation = yes, gen_vel = no, tpi
>>>             integrator) for a pdb file or use velocities from
>>>             previous simulations (gro file)?
>>>             If the second option is more appropriate what velocity
>>>             shall I adjust to the extra water molecule?
>>>
>>>             I will appreciate your reply.
>>>
>>>             Steven
>>>
>>>
>>
>>             -- 
>>             Javier CEREZO BASTIDA
>>             PhD Student
>>             Physical Chemistry
>>             Universidad de Murcia
>>             Murcia (Spain)
>>             Tel: (+34)868887434 <tel:%28%2B34%29868887434>
>>
>>             --
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>>
>>
>>
>>
>
>         -- 
>         Javier CEREZO BASTIDA
>         PhD Student
>         Physical Chemistry
>         Universidad de Murcia
>         Murcia (Spain)
>         Tel: (+34)868887434 <tel:%28%2B34%29868887434>
>
>         --
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>
>
>
>
>

-- 
Javier CEREZO BASTIDA
PhD Student
Physical Chemistry
Universidad de Murcia
Murcia (Spain)
Tel: (+34)868887434
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