[gmx-users] implicit solvent error

Chhaya Singh chhayasingh014 at gmail.com
Sun Jun 24 10:06:26 CEST 2018


sorry i attached a wrong file.
this is my inputs about the implcit solvent



 integrator          =  md
dt                  =  0.005    ; ps !
nsteps              =  20000000 ; total 10 ns.

nstlog                  = 5000
nstxout                 = 0  ;1000
nstvout                 = 0  ;1000
nstfout                 = 0  ;1000
nstxtcout               = 5000
nstenergy               = 5000

nstlist             =  10

cutoff-scheme       = group

rlist               =  5
rvdw                =  5
rcoulomb            = 5
coulombtype         = cut-off
vdwtype             = cut-off
bd_fric             =  0
;ld_seed             =  -1
pbc                 =  no
ns_type             =  simple
constraints         = all-bonds
lincs_order         = 4
lincs_iter          = 1
lincs-warnangle     = 30

Tcoupl              = v-rescale
tau_t               = 1.0
tc-grps             =  Protein
ref_t               =  300

Pcoupl              =  no

gen_vel             =  yes
gen_temp            =  300
gen_seed            =  173529
;http://www.mail-archive.com/gmx-users@gromacs.org/msg20866.html

;mine addition
comm_mode       = angular
nstcomm         = 10

; IMPLICIT SOLVENT ALGORITHM
implicit_solvent         = gbsa

; GENERALIZED BORN ELECTROSTATICS
; Algorithm for calculating Born radii
gb_algorithm             = OBC  ;Still
; Frequency of calculating the Born radii inside rlist
nstgbradii               = 1
; Cutoff for Born radii calculation; the contribution from atoms
; between rlist and rgbradii is updated every nstlist steps
rgbradii                 = 5
; Dielectric coefficient of the implicit solvent
gb_epsilon_solvent       = 80
; Salt concentration in M for Generalized Born models
gb_saltconc              = 0
; Scaling factors used in the OBC GB model. Default values are OBC(II)
gb_obc_alpha             = 1
gb_obc_beta              = 0.8
gb_obc_gamma             = 4.85
gb_dielectric_offset     = 0.009
sa_algorithm             = Ace-approximation
; Surface tension (kJ/mol/nm^2) for the SA (nonpolar surface) part of GBSA
; The value -1 will set default value for Still/HCT/OBC GB-models.
sa_surface_tension       = -1



1,1           Top


On 24 June 2018 at 13:17, Alex <nedomacho at gmail.com> wrote:

> Your EM is unrelated to dynamics. I mean, it could, but we don't know
> anything about your simulated system. I am of course assuming that your MPI
> setup is optimal for gmx and you actually get to use those 16 threads,
> assuming those aren't an emulation of some sort.
>
>
>
> On 6/24/2018 1:33 AM, Chhaya Singh wrote:
>
>> Hi,
>> I have attached the energy minimization mdp file.
>> please look through it .
>>
>>
>>
>> cpp                 =
>> /lib/cpp                                                 ; prepocessor of
>> the current machine
>> define              =
>> -DFLEXIBLE                                               ; -DPOSRES,
>> -DPOSRES_IONS ;DFLEX_SPC; FLEXible SPC and POSition REStraints
>>
>> integrator          =
>> steep                                                    ; steepest
>> descent
>> algorithm
>> dt                  =
>> 0.005                                                    ; time step in ps
>> nsteps              =
>> 5000                                                     ; number of steps
>>
>> emtol               =
>> 100                                                      ; convergence
>> criterion
>> emstep              =
>> 0.05                                                     ; intial step
>> size
>> constraints           = none
>> constraint-algorithm  = lincs
>> unconstrained-start   =
>> no                                                      ; Do not constrain
>> the start configuration
>> ;shake_tol           = 0.0001
>> nstlist             =
>> 0                                                        ; step frequency
>> for updating neighbour list
>> ns_type             =
>> simple                                                   ; grid ; method
>> for nighbour searching (?)
>> nstxout             =
>> 100                                                      ; frequency for
>> writing coords to output
>> nstvout             =
>> 100                                                      ; frequency for
>> writing velocities to output
>> nstfout             =  0    ; frequency for writing forces to output
>> nstlog              =  100    ; frequency for writing energies to log file
>> nstenergy           =  100  ; frequency for writing energies to energy
>> file
>> nstxtcout           =  0    ; frequency for writing coords to xtc traj
>> xtc_grps            =  system ; group(s) whose coords are to be written in
>> xtc traj
>> energygrps          =  system ; group(s) whose energy is to be written in
>> energy file
>> pbc                 =  no    ; use pbc
>> rlist               =  1.4    ; cutoff (nm)
>> coulombtype         =  cutoff ; truncation for minimisation, with large
>> cutoff
>> rcoulomb            =  1.4
>> vdwtype             =  cut-off  ; truncation for minimisation, with large
>> cutoff
>> rvdw                =  1.4
>> nstcomm             =  0  ; number of steps for centre of mass motion
>> removal (in vacuo only!)
>> Tcoupl              =  no
>> Pcoupl              =  no
>> "min-implicit.mdp" 40L,
>> 2616C
>> 1,1           Top
>>
>>
>>
>> the system I am using has the following information:
>> PBS -l select=1:ncpus=16:mpiprocs=16
>> #PBS -l walltime=24:00:00
>>
>>
>>
>> On 24 June 2018 at 13:00, Alex <nedomacho at gmail.com> wrote:
>>
>> This input has no information about implicit solvent and a simple google
>>> search immediately yields mdp examples using gbsa. As far as performance
>>> is
>>> concerned, we don't know the specs of your machine or the size of your
>>> system. With cutoff electrostatics and a cutoff of 5 nm, one can expect
>>> quite a bit of scaling with system size beyond linear.
>>>
>>> Alex
>>>
>>>
>>>
>>> On 6/24/2018 1:04 AM, Chhaya Singh wrote:
>>>
>>> Hi,
>>>>
>>>> I am trying to simulate a protein in an implicit solvent in groamcs
>>>> using
>>>> amber ff99sb ildn .
>>>> the mdpfile that I am using is I have shown below:
>>>>
>>>>
>>>> integrator          =  md
>>>> dt                  =  0.001 ;0.005    ; ps !
>>>> nsteps              =  5000000 ; total 5 ns.
>>>>
>>>> nstlog                  = 5000
>>>> nstxout                 = 0  ;1000
>>>> nstvout                 = 0  ;1000
>>>> nstfout                 = 0  ;1000
>>>> nstxtcout               = 5000
>>>> nstenergy               = 5000
>>>>
>>>> nstlist             =  10
>>>>
>>>> cutoff-scheme       = group
>>>>
>>>> rlist               =  5
>>>> rvdw                =  5
>>>> rcoulomb            =  5
>>>> coulombtype         = cut-off
>>>> vdwtype             = cut-off
>>>> bd_fric             =  0
>>>> ;ld_seed             =  -1
>>>> pbc                 =  no
>>>> ns_type             =  grid  ;simple => gives domain decomposition error
>>>> constraints         = all-bonds
>>>> lincs_order         = 4
>>>> lincs_iter          = 1
>>>> lincs-warnangle     = 30
>>>>
>>>> Tcoupl              = v-rescale
>>>> tau_t               = 1.0
>>>> tc-grps             = Protein
>>>> ref_t               = 310
>>>>
>>>>
>>>>
>>>> This is the mdp file that I am using for equilibration and production
>>>> run,
>>>> if there is anything that I can fix in mdp file please let me know.
>>>> I am getting very less speed using an implicit solvent in gromacs.
>>>> is there any way to increase the speed.
>>>> the speed right now I am getting is 0.47- 0.74 ns /day using one node.
>>>> please help.
>>>>
>>>> --
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