Re: [gmx-users] stopped simulation

2013-11-06 Thread Justin Lemkul



On 11/6/13 4:52 PM, Mark Abraham wrote:

On Wed, Nov 6, 2013 at 8:22 PM, Justin Lemkul  wrote:




On 11/6/13 2:14 PM, Ehsan Sadeghi wrote:


Many thanks Justin. What is an appropriate cut-off value? My box size is
d=
0.5 nm; based on the definition of cut-off radius, its value shouble be
smaller than d/2; therefore 0.24 is an appropriate cut-off value. Am I
right?



No.  The cutoff value is not a function of box size; it is a fixed
property of the force field.  No wonder the simulation is crashing.  If
your box is only 0.5 nm, then a cutoff of 1.5 nm is triple-counting
interactions across PBC!



Triple counting is not possible, per minimum-image convention. I think


True.  Thinking too quickly ;)


Ehsan's report of a "0.5nm" box size is probably wrong, e.g. per its
documentation, editconf -d 0.5 does not produce a 0.5nm box.



editconf -box 0.5 does produce such a box, though, so it is possible.  grompp 
should have warned quite obviously about the combination of a 0.5-nm box with 
1.5-nm cutoffs, though.


-Justin

--
==

Justin A. Lemkul, Ph.D.
Postdoctoral Fellow

Department of Pharmaceutical Sciences
School of Pharmacy
Health Sciences Facility II, Room 601
University of Maryland, Baltimore
20 Penn St.
Baltimore, MD 21201

jalem...@outerbanks.umaryland.edu | (410) 706-7441

==
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Re: [gmx-users] stopped simulation

2013-11-06 Thread Mark Abraham
On Wed, Nov 6, 2013 at 8:22 PM, Justin Lemkul  wrote:

>
>
> On 11/6/13 2:14 PM, Ehsan Sadeghi wrote:
>
>> Many thanks Justin. What is an appropriate cut-off value? My box size is
>> d=
>> 0.5 nm; based on the definition of cut-off radius, its value shouble be
>> smaller than d/2; therefore 0.24 is an appropriate cut-off value. Am I
>> right?
>>
>>
> No.  The cutoff value is not a function of box size; it is a fixed
> property of the force field.  No wonder the simulation is crashing.  If
> your box is only 0.5 nm, then a cutoff of 1.5 nm is triple-counting
> interactions across PBC!
>

Triple counting is not possible, per minimum-image convention. I think
Ehsan's report of a "0.5nm" box size is probably wrong, e.g. per its
documentation, editconf -d 0.5 does not produce a 0.5nm box.

Mark

Refer to the primary literature for the Gromos parameter set you are using
> for proper settings.  You haven't said which one you're using, and there
> may be slight differences between them.  If the value you're using isn't
> taken directly from a paper, it's not credible.
>
> -Justin
>
>
>  Cheers, Ehsan
>>
>> - Original Message ----- From: "Justin Lemkul"  To:
>> "Discussion list for GROMACS users"  Sent:
>> Wednesday,
>> November 6, 2013 10:54:42 AM Subject: Re: [gmx-users] stopped simulation
>>
>>
>>
>> On 11/6/13 12:53 PM, Ehsan Sadeghi wrote:
>>
>>> Hi gmx users,
>>>
>>> I have simulated ionomer in water solution using gromos force field. But
>>> in
>>> middle of simulation(after 2 ns) the simulation stopped and I received
>>> these messages:
>>>
>>>
>>> WARNING: Listed nonbonded interaction between particles 174 and 188 at
>>> distance 3f which is larger than the table limit 3f nm.
>>>
>>> This is likely either a 1,4 interaction, or a listed interaction inside a
>>> smaller molecule you are decoupling during a free energy calculation.
>>> Since
>>> interactions at distances beyond the table cannot be computed, they are
>>> skipped until they are inside the table limit again. You will only see
>>> this
>>> message once, even if it occurs for several interactions.
>>>
>>> IMPORTANT: This should not happen in a stable simulation, so there is
>>> probably something wrong with your system. Only change the
>>> table-extension
>>> distance in the mdp file if you are really sure that is the reason.
>>>
>>> Fatal error: 1 particles communicated to PME node 5 are more than 2/3
>>> times
>>> the cut-off out of the domain decomposition cell of their charge group in
>>> dimension y. This usually means that your system is not well
>>> equilibrated.
>>>
>>>
>>>  I used simulated annealing for equilibrating the system in NVT and
>>> NPT
>>> condition. The mdp files are:
>>>
>>>  NVT --
>>>
>>> define = -DPOSRES integrator = md dt = 0.002 ; time step (in
>>> ps) nsteps = 25000 ; Maximum number of steps to perform
>>>
>>> ; OUTPUT CONTROL OPTIONS nstxout= 500 nstvout= 500 nstenergy  =
>>> 500 nstlog = 500 energygrps = Non-Water Water
>>>
>>> ; NEIGHBORSEARCHING PARAMETERS
>>>
>>> nstlist= 1 ns_type= grid rlist  = 1.5 pbc= xyz
>>>
>>> ; OPTIONS FOR ELECTROSTATICS AND VDW
>>>
>>> coulombtype= PME pme_order  = 4 fourierspacing= 0.16 rcoulomb   = 1.5
>>> vdw-type   = Cut-off rvdw   = 1.5
>>>
>>> ; Temperature coupling
>>>
>>> tcoupl = v-rescale tc-grps= Non-Water Water tau_t  = 0.1
>>> 0.1 ref_t  = 300300 ; Dispersion correction DispCorr   =
>>> EnerPres ;
>>> Pressure coupling is off pcoupl = no
>>>
>>> ; Annealing
>>>
>>> annealing   = single single annealing-npoints = 5  5 annealing-time = 0
>>> 10
>>> 20 30 40 0 10 20 30 40 annealing-temp = 300 320 340 360 380 300 320 340
>>> 360
>>> 380
>>>
>>> ; GENERATE VELOCITIES FOR STARTUP RUN gen_vel= yes gen_temp   = 300
>>> gen_seed   = -1
>>>
>>> ; OPTIONS FOR BONDS constraints = ; all-bonds continuation= no
>>> constraint_algorithm = lincs lincs_iter = 1 lincs_order= 4
>>>
>>> - NPT 
>>>
>>> define = -DPOSRES integrator = md dt = 0.002 nsteps =
>>> 25000
>>>

Re: [gmx-users] stopped simulation

2013-11-06 Thread Justin Lemkul



On 11/6/13 2:27 PM, Ehsan Sadeghi wrote:

What is this cut-off radius mentioned in the manual? The cut-off radius used
to truncate non-bonded inter-actions may not exceed half the shortest box
vector.



It refers to the longest cutoff used to evaluate nonbonded interactions, 
whatever that may be for your chosen force field.


http://www.gromacs.org/Documentation/Terminology/Minimum_Image_Convention

-Justin


Cheers, Ehsan

- Original Message - From: "Justin Lemkul"  To:
"Discussion list for GROMACS users"  Sent: Wednesday,
November 6, 2013 11:22:09 AM Subject: Re: [gmx-users] stopped simulation



On 11/6/13 2:14 PM, Ehsan Sadeghi wrote:

Many thanks Justin. What is an appropriate cut-off value? My box size is
d= 0.5 nm; based on the definition of cut-off radius, its value shouble be
smaller than d/2; therefore 0.24 is an appropriate cut-off value. Am I
right?



No.  The cutoff value is not a function of box size; it is a fixed property
of the force field.  No wonder the simulation is crashing.  If your box is
only 0.5 nm, then a cutoff of 1.5 nm is triple-counting interactions across
PBC!

Refer to the primary literature for the Gromos parameter set you are using
for proper settings.  You haven't said which one you're using, and there may
be slight differences between them.  If the value you're using isn't taken
directly from a paper, it's not credible.

-Justin


Cheers, Ehsan

- Original Message - From: "Justin Lemkul"  To:
"Discussion list for GROMACS users"  Sent:
Wednesday, November 6, 2013 10:54:42 AM Subject: Re: [gmx-users] stopped
simulation



On 11/6/13 12:53 PM, Ehsan Sadeghi wrote:

Hi gmx users,

I have simulated ionomer in water solution using gromos force field. But
in middle of simulation(after 2 ns) the simulation stopped and I
received these messages:


WARNING: Listed nonbonded interaction between particles 174 and 188 at
distance 3f which is larger than the table limit 3f nm.

This is likely either a 1,4 interaction, or a listed interaction inside
a smaller molecule you are decoupling during a free energy calculation.
Since interactions at distances beyond the table cannot be computed, they
are skipped until they are inside the table limit again. You will only
see this message once, even if it occurs for several interactions.

IMPORTANT: This should not happen in a stable simulation, so there is
probably something wrong with your system. Only change the
table-extension distance in the mdp file if you are really sure that is
the reason.

Fatal error: 1 particles communicated to PME node 5 are more than 2/3
times the cut-off out of the domain decomposition cell of their charge
group in dimension y. This usually means that your system is not well
equilibrated.


 I used simulated annealing for equilibrating the system in NVT and
NPT condition. The mdp files are:

 NVT --

define = -DPOSRES integrator = md dt = 0.002 ; time step (in
ps) nsteps = 25000 ; Maximum number of steps to perform

; OUTPUT CONTROL OPTIONS nstxout= 500 nstvout= 500 nstenergy  =
500 nstlog = 500 energygrps = Non-Water Water

; NEIGHBORSEARCHING PARAMETERS

nstlist= 1 ns_type= grid rlist  = 1.5 pbc= xyz

; OPTIONS FOR ELECTROSTATICS AND VDW

coulombtype= PME pme_order  = 4 fourierspacing= 0.16 rcoulomb   = 1.5
vdw-type   = Cut-off rvdw   = 1.5

; Temperature coupling

tcoupl = v-rescale tc-grps= Non-Water Water tau_t  = 0.1 0.1
ref_t  = 300300 ; Dispersion correction DispCorr   = EnerPres ;
Pressure coupling is off pcoupl = no

; Annealing

annealing   = single single annealing-npoints = 5  5 annealing-time = 0
10 20 30 40 0 10 20 30 40 annealing-temp = 300 320 340 360 380 300 320
340 360 380

; GENERATE VELOCITIES FOR STARTUP RUN gen_vel= yes gen_temp   = 300
gen_seed   = -1

; OPTIONS FOR BONDS constraints = ; all-bonds continuation= no
constraint_algorithm = lincs lincs_iter = 1 lincs_order= 4

- NPT 

define = -DPOSRES integrator = md dt = 0.002 nsteps =
25000

; OUTPUT CONTROL OPTIONS nstxout= 500 nstvout= 500 nstfout=
500 nstenergy  = 500 nstlog = 500 energygrps = Non-Water Water

; NEIGHBORSEARCHING PARAMETERS

nstlist= 5 ns_type= grid rlist  = 1.5 pbc= xyz

; OPTIONS FOR ELECTROSTATICS AND VDW

coulombtype= PME pme_order  = 4 fourierspacing= 0.16 rcoulomb   = 1.5
vdw-type   = Cut-off rvdw   = 1.5

; Temperature coupling

tcoupl = v-rescale tc-grps= Non-Water Water tau_t  = 0.1 0.1
ref_t  = 300300 ; Dispersion correction DispCorr   = EnerPres

pcoupl = Parrinello-Rahman Pcoupltype = Isotropic tau_p  = 2.0
compressibility = 4.5e-5 ref_p  = 1.0 refcoord_scaling = com

; Annealing

annealing   = single single annealing-npoints = 5  5 annealing-time = 0
10 20 30 40 0 10 20 30 40 annealing-temp = 380 360 340 320 300 380 360
34

Re: [gmx-users] stopped simulation

2013-11-06 Thread Ehsan Sadeghi
What is this cut-off radius mentioned in the manual? The cut-off radius used to 
truncate non-bonded inter-actions may not exceed half the shortest box vector.

Cheers,
Ehsan

- Original Message -
From: "Justin Lemkul" 
To: "Discussion list for GROMACS users" 
Sent: Wednesday, November 6, 2013 11:22:09 AM
Subject: Re: [gmx-users] stopped simulation



On 11/6/13 2:14 PM, Ehsan Sadeghi wrote:
> Many thanks Justin. What is an appropriate cut-off value? My box size is d=
> 0.5 nm; based on the definition of cut-off radius, its value shouble be
> smaller than d/2; therefore 0.24 is an appropriate cut-off value. Am I
> right?
>

No.  The cutoff value is not a function of box size; it is a fixed property of 
the force field.  No wonder the simulation is crashing.  If your box is only 
0.5 
nm, then a cutoff of 1.5 nm is triple-counting interactions across PBC!

Refer to the primary literature for the Gromos parameter set you are using for 
proper settings.  You haven't said which one you're using, and there may be 
slight differences between them.  If the value you're using isn't taken 
directly 
from a paper, it's not credible.

-Justin

> Cheers, Ehsan
>
> - Original Message - From: "Justin Lemkul"  To:
> "Discussion list for GROMACS users"  Sent: Wednesday,
> November 6, 2013 10:54:42 AM Subject: Re: [gmx-users] stopped simulation
>
>
>
> On 11/6/13 12:53 PM, Ehsan Sadeghi wrote:
>> Hi gmx users,
>>
>> I have simulated ionomer in water solution using gromos force field. But in
>> middle of simulation(after 2 ns) the simulation stopped and I received
>> these messages:
>>
>>
>> WARNING: Listed nonbonded interaction between particles 174 and 188 at
>> distance 3f which is larger than the table limit 3f nm.
>>
>> This is likely either a 1,4 interaction, or a listed interaction inside a
>> smaller molecule you are decoupling during a free energy calculation. Since
>> interactions at distances beyond the table cannot be computed, they are
>> skipped until they are inside the table limit again. You will only see this
>> message once, even if it occurs for several interactions.
>>
>> IMPORTANT: This should not happen in a stable simulation, so there is
>> probably something wrong with your system. Only change the table-extension
>> distance in the mdp file if you are really sure that is the reason.
>>
>> Fatal error: 1 particles communicated to PME node 5 are more than 2/3 times
>> the cut-off out of the domain decomposition cell of their charge group in
>> dimension y. This usually means that your system is not well equilibrated.
>>
>>
>>  I used simulated annealing for equilibrating the system in NVT and NPT
>> condition. The mdp files are:
>>
>>  NVT --
>>
>> define = -DPOSRES integrator = md dt = 0.002 ; time step (in
>> ps) nsteps = 25000 ; Maximum number of steps to perform
>>
>> ; OUTPUT CONTROL OPTIONS nstxout= 500 nstvout= 500 nstenergy  =
>> 500 nstlog = 500 energygrps = Non-Water Water
>>
>> ; NEIGHBORSEARCHING PARAMETERS
>>
>> nstlist= 1 ns_type= grid rlist  = 1.5 pbc= xyz
>>
>> ; OPTIONS FOR ELECTROSTATICS AND VDW
>>
>> coulombtype= PME pme_order  = 4 fourierspacing= 0.16 rcoulomb   = 1.5
>> vdw-type   = Cut-off rvdw   = 1.5
>>
>> ; Temperature coupling
>>
>> tcoupl = v-rescale tc-grps= Non-Water Water tau_t  = 0.1
>> 0.1 ref_t  = 300300 ; Dispersion correction DispCorr   = EnerPres ;
>> Pressure coupling is off pcoupl = no
>>
>> ; Annealing
>>
>> annealing   = single single annealing-npoints = 5  5 annealing-time = 0 10
>> 20 30 40 0 10 20 30 40 annealing-temp = 300 320 340 360 380 300 320 340 360
>> 380
>>
>> ; GENERATE VELOCITIES FOR STARTUP RUN gen_vel= yes gen_temp   = 300
>> gen_seed   = -1
>>
>> ; OPTIONS FOR BONDS constraints = ; all-bonds continuation= no
>> constraint_algorithm = lincs lincs_iter = 1 lincs_order= 4
>>
>> - NPT 
>>
>> define = -DPOSRES integrator = md dt = 0.002 nsteps =
>> 25000
>>
>> ; OUTPUT CONTROL OPTIONS nstxout= 500 nstvout= 500 nstfout=
>> 500 nstenergy  = 500 nstlog = 500 energygrps = Non-Water Water
>>
>> ; NEIGHBORSEARCHING PARAMETERS
>>
>> nstlist= 5 ns_type= grid rlist  = 1.5 pbc= xyz
>>
>> ; OPTIONS FOR ELECTROSTATICS AND VDW
>>
>> coulombtype= PME pme_order  = 4 fourierspacing= 0.16 rcoulomb   = 1.5
>> vdw-type  

Re: [gmx-users] stopped simulation

2013-11-06 Thread Justin Lemkul



On 11/6/13 2:14 PM, Ehsan Sadeghi wrote:

Many thanks Justin. What is an appropriate cut-off value? My box size is d=
0.5 nm; based on the definition of cut-off radius, its value shouble be
smaller than d/2; therefore 0.24 is an appropriate cut-off value. Am I
right?



No.  The cutoff value is not a function of box size; it is a fixed property of 
the force field.  No wonder the simulation is crashing.  If your box is only 0.5 
nm, then a cutoff of 1.5 nm is triple-counting interactions across PBC!


Refer to the primary literature for the Gromos parameter set you are using for 
proper settings.  You haven't said which one you're using, and there may be 
slight differences between them.  If the value you're using isn't taken directly 
from a paper, it's not credible.


-Justin


Cheers, Ehsan

- Original Message - From: "Justin Lemkul"  To:
"Discussion list for GROMACS users"  Sent: Wednesday,
November 6, 2013 10:54:42 AM Subject: Re: [gmx-users] stopped simulation



On 11/6/13 12:53 PM, Ehsan Sadeghi wrote:

Hi gmx users,

I have simulated ionomer in water solution using gromos force field. But in
middle of simulation(after 2 ns) the simulation stopped and I received
these messages:


WARNING: Listed nonbonded interaction between particles 174 and 188 at
distance 3f which is larger than the table limit 3f nm.

This is likely either a 1,4 interaction, or a listed interaction inside a
smaller molecule you are decoupling during a free energy calculation. Since
interactions at distances beyond the table cannot be computed, they are
skipped until they are inside the table limit again. You will only see this
message once, even if it occurs for several interactions.

IMPORTANT: This should not happen in a stable simulation, so there is
probably something wrong with your system. Only change the table-extension
distance in the mdp file if you are really sure that is the reason.

Fatal error: 1 particles communicated to PME node 5 are more than 2/3 times
the cut-off out of the domain decomposition cell of their charge group in
dimension y. This usually means that your system is not well equilibrated.


 I used simulated annealing for equilibrating the system in NVT and NPT
condition. The mdp files are:

 NVT --

define = -DPOSRES integrator = md dt = 0.002 ; time step (in
ps) nsteps = 25000 ; Maximum number of steps to perform

; OUTPUT CONTROL OPTIONS nstxout= 500 nstvout= 500 nstenergy  =
500 nstlog = 500 energygrps = Non-Water Water

; NEIGHBORSEARCHING PARAMETERS

nstlist= 1 ns_type= grid rlist  = 1.5 pbc= xyz

; OPTIONS FOR ELECTROSTATICS AND VDW

coulombtype= PME pme_order  = 4 fourierspacing= 0.16 rcoulomb   = 1.5
vdw-type   = Cut-off rvdw   = 1.5

; Temperature coupling

tcoupl = v-rescale tc-grps= Non-Water Water tau_t  = 0.1
0.1 ref_t  = 300300 ; Dispersion correction DispCorr   = EnerPres ;
Pressure coupling is off pcoupl = no

; Annealing

annealing   = single single annealing-npoints = 5  5 annealing-time = 0 10
20 30 40 0 10 20 30 40 annealing-temp = 300 320 340 360 380 300 320 340 360
380

; GENERATE VELOCITIES FOR STARTUP RUN gen_vel= yes gen_temp   = 300
gen_seed   = -1

; OPTIONS FOR BONDS constraints = ; all-bonds continuation= no
constraint_algorithm = lincs lincs_iter = 1 lincs_order= 4

- NPT 

define = -DPOSRES integrator = md dt = 0.002 nsteps =
25000

; OUTPUT CONTROL OPTIONS nstxout= 500 nstvout= 500 nstfout=
500 nstenergy  = 500 nstlog = 500 energygrps = Non-Water Water

; NEIGHBORSEARCHING PARAMETERS

nstlist= 5 ns_type= grid rlist  = 1.5 pbc= xyz

; OPTIONS FOR ELECTROSTATICS AND VDW

coulombtype= PME pme_order  = 4 fourierspacing= 0.16 rcoulomb   = 1.5
vdw-type   = Cut-off rvdw   = 1.5

; Temperature coupling

tcoupl = v-rescale tc-grps= Non-Water Water tau_t  = 0.1
0.1 ref_t  = 300300 ; Dispersion correction DispCorr   = EnerPres

pcoupl = Parrinello-Rahman Pcoupltype = Isotropic tau_p  = 2.0
compressibility = 4.5e-5 ref_p  = 1.0 refcoord_scaling = com

; Annealing

annealing   = single single annealing-npoints = 5  5 annealing-time = 0 10
20 30 40 0 10 20 30 40 annealing-temp = 380 360 340 320 300 380 360 340 320
300


; GENERATE VELOCITIES FOR STARTUP RUN gen_vel= no

; OPTIONS FOR BONDS constraints = ; all-bonds continuation= yes
;continuation from NVT constraint_algorithm = lincs lincs_iter = 1
lincs_order= 4 --

Is the equilibration time is long enough? I appreciate any help/suggestion
regarding my case.



The cutoffs values (1.5) are wrong for using any of the Gromos parameter
sets. Likely the dynamics have become unstable due to violation of the
physical model.

-Justin



--
==

Justin A. Lemkul, Ph.D.
Postdoctoral Fellow

Department of Phar

Re: [gmx-users] stopped simulation

2013-11-06 Thread Ehsan Sadeghi
Many thanks Justin. What is an appropriate cut-off value? My box size is d= 0.5 
nm; based on the definition of cut-off radius, its value shouble be smaller 
than d/2; therefore 0.24 is an appropriate cut-off value. Am I right?

Cheers,
Ehsan

- Original Message -
From: "Justin Lemkul" 
To: "Discussion list for GROMACS users" 
Sent: Wednesday, November 6, 2013 10:54:42 AM
Subject: Re: [gmx-users] stopped simulation



On 11/6/13 12:53 PM, Ehsan Sadeghi wrote:
> Hi gmx users,
>
> I have simulated ionomer in water solution using gromos force field. But in 
> middle of simulation(after 2 ns) the simulation stopped and I received these 
> messages:
>
>
> WARNING: Listed nonbonded interaction between particles 174 and 188
> at distance 3f which is larger than the table limit 3f nm.
>
> This is likely either a 1,4 interaction, or a listed interaction inside
> a smaller molecule you are decoupling during a free energy calculation.
> Since interactions at distances beyond the table cannot be computed,
> they are skipped until they are inside the table limit again. You will
> only see this message once, even if it occurs for several interactions.
>
> IMPORTANT: This should not happen in a stable simulation, so there is
> probably something wrong with your system. Only change the table-extension
> distance in the mdp file if you are really sure that is the reason.
>
> Fatal error:
> 1 particles communicated to PME node 5 are more than 2/3 times the cut-off 
> out of the domain decomposition cell of their charge group in dimension y.
> This usually means that your system is not well equilibrated.
>
>
> 
> I used simulated annealing for equilibrating the system in NVT and NPT 
> condition. The mdp files are:
>
>  NVT --
>
> define = -DPOSRES
> integrator = md
> dt = 0.002 ; time step (in ps)
> nsteps = 25000 ; Maximum number of steps to perform
>
> ; OUTPUT CONTROL OPTIONS
> nstxout= 500
> nstvout= 500
> nstenergy  = 500
> nstlog = 500
> energygrps = Non-Water Water
>
> ; NEIGHBORSEARCHING PARAMETERS
>
> nstlist= 1
> ns_type= grid
> rlist  = 1.5
> pbc= xyz
>
> ; OPTIONS FOR ELECTROSTATICS AND VDW
>
> coulombtype= PME
> pme_order  = 4
> fourierspacing= 0.16
> rcoulomb   = 1.5
> vdw-type   = Cut-off
> rvdw   = 1.5
>
> ; Temperature coupling
>
> tcoupl = v-rescale
> tc-grps= Non-Water Water
> tau_t  = 0.10.1
> ref_t  = 300300
> ; Dispersion correction
> DispCorr   = EnerPres
> ; Pressure coupling is off
> pcoupl = no
>
> ; Annealing
>
> annealing   = single single
> annealing-npoints = 5  5
> annealing-time = 0 10 20 30 40 0 10 20 30 40
> annealing-temp = 300 320 340 360 380 300 320 340 360 380
>
> ; GENERATE VELOCITIES FOR STARTUP RUN
> gen_vel= yes
> gen_temp   = 300
> gen_seed   = -1
>
> ; OPTIONS FOR BONDS
> constraints = ; all-bonds
> continuation= no
> constraint_algorithm = lincs
> lincs_iter = 1
> lincs_order= 4
>
> - NPT 
>
> define = -DPOSRES
> integrator = md
> dt = 0.002
> nsteps = 25000
>
> ; OUTPUT CONTROL OPTIONS
> nstxout= 500
> nstvout= 500
> nstfout= 500
> nstenergy  = 500
> nstlog = 500
> energygrps = Non-Water Water
>
> ; NEIGHBORSEARCHING PARAMETERS
>
> nstlist= 5
> ns_type= grid
> rlist  = 1.5
> pbc= xyz
>
> ; OPTIONS FOR ELECTROSTATICS AND VDW
>
> coulombtype= PME
> pme_order  = 4
> fourierspacing= 0.16
> rcoulomb   = 1.5
> vdw-type   = Cut-off
> rvdw   = 1.5
>
> ; Temperature coupling
>
> tcoupl = v-rescale
> tc-grps= Non-Water Water
> tau_t  = 0.10.1
> ref_t  = 300300
> ; Dispersion correction
> DispCorr   = EnerPres
>
> pcoupl = Parrinello-Rahman
> Pcoupltype = Isotropic
> tau_p  = 2.0
> compressibility = 4.5e-5
> ref_p  = 1.0
> refcoord_scaling = com
>
> ; Annealing
>
> annealing   = single single
> annealing-npoints = 5  5
> annealing-time = 0 10 20 30 40 0 10 20 30 40
> annealing-temp = 380 360 340 320 300 380 360 340 320 300
>
>
> ; GENERATE VELOCITIES FOR STARTUP RUN
> gen_vel= no
>
> ; OPTIONS FOR BONDS
> constraints = ; all-bonds
> continuation= yes ;continuation from NVT
> constraint_algorithm = lincs
> lincs_iter = 1
> lincs_order= 4
> --
>
> Is the equilibration time is long enough? I appreciate any help/suggestion 
> regarding my case.
>

The cutoffs values (1.5) are wrong for using any of the Gromos parameter sets. 
Likely the dynamics have become unst

Re: [gmx-users] stopped simulation

2013-11-06 Thread Justin Lemkul



On 11/6/13 12:53 PM, Ehsan Sadeghi wrote:

Hi gmx users,

I have simulated ionomer in water solution using gromos force field. But in 
middle of simulation(after 2 ns) the simulation stopped and I received these 
messages:


WARNING: Listed nonbonded interaction between particles 174 and 188
at distance 3f which is larger than the table limit 3f nm.

This is likely either a 1,4 interaction, or a listed interaction inside
a smaller molecule you are decoupling during a free energy calculation.
Since interactions at distances beyond the table cannot be computed,
they are skipped until they are inside the table limit again. You will
only see this message once, even if it occurs for several interactions.

IMPORTANT: This should not happen in a stable simulation, so there is
probably something wrong with your system. Only change the table-extension
distance in the mdp file if you are really sure that is the reason.

Fatal error:
1 particles communicated to PME node 5 are more than 2/3 times the cut-off out 
of the domain decomposition cell of their charge group in dimension y.
This usually means that your system is not well equilibrated.



I used simulated annealing for equilibrating the system in NVT and NPT 
condition. The mdp files are:

 NVT --

define = -DPOSRES
integrator = md
dt = 0.002 ; time step (in ps)
nsteps = 25000 ; Maximum number of steps to perform

; OUTPUT CONTROL OPTIONS
nstxout= 500
nstvout= 500
nstenergy  = 500
nstlog = 500
energygrps = Non-Water Water

; NEIGHBORSEARCHING PARAMETERS

nstlist= 1
ns_type= grid
rlist  = 1.5
pbc= xyz

; OPTIONS FOR ELECTROSTATICS AND VDW

coulombtype= PME
pme_order  = 4
fourierspacing= 0.16
rcoulomb   = 1.5
vdw-type   = Cut-off
rvdw   = 1.5

; Temperature coupling

tcoupl = v-rescale
tc-grps= Non-Water Water
tau_t  = 0.10.1
ref_t  = 300300
; Dispersion correction
DispCorr   = EnerPres
; Pressure coupling is off
pcoupl = no

; Annealing

annealing   = single single
annealing-npoints = 5  5
annealing-time = 0 10 20 30 40 0 10 20 30 40
annealing-temp = 300 320 340 360 380 300 320 340 360 380

; GENERATE VELOCITIES FOR STARTUP RUN
gen_vel= yes
gen_temp   = 300
gen_seed   = -1

; OPTIONS FOR BONDS
constraints = ; all-bonds
continuation= no
constraint_algorithm = lincs
lincs_iter = 1
lincs_order= 4

- NPT 

define = -DPOSRES
integrator = md
dt = 0.002
nsteps = 25000

; OUTPUT CONTROL OPTIONS
nstxout= 500
nstvout= 500
nstfout= 500
nstenergy  = 500
nstlog = 500
energygrps = Non-Water Water

; NEIGHBORSEARCHING PARAMETERS

nstlist= 5
ns_type= grid
rlist  = 1.5
pbc= xyz

; OPTIONS FOR ELECTROSTATICS AND VDW

coulombtype= PME
pme_order  = 4
fourierspacing= 0.16
rcoulomb   = 1.5
vdw-type   = Cut-off
rvdw   = 1.5

; Temperature coupling

tcoupl = v-rescale
tc-grps= Non-Water Water
tau_t  = 0.10.1
ref_t  = 300300
; Dispersion correction
DispCorr   = EnerPres

pcoupl = Parrinello-Rahman
Pcoupltype = Isotropic
tau_p  = 2.0
compressibility = 4.5e-5
ref_p  = 1.0
refcoord_scaling = com

; Annealing

annealing   = single single
annealing-npoints = 5  5
annealing-time = 0 10 20 30 40 0 10 20 30 40
annealing-temp = 380 360 340 320 300 380 360 340 320 300


; GENERATE VELOCITIES FOR STARTUP RUN
gen_vel= no

; OPTIONS FOR BONDS
constraints = ; all-bonds
continuation= yes ;continuation from NVT
constraint_algorithm = lincs
lincs_iter = 1
lincs_order= 4
--

Is the equilibration time is long enough? I appreciate any help/suggestion 
regarding my case.



The cutoffs values (1.5) are wrong for using any of the Gromos parameter sets. 
Likely the dynamics have become unstable due to violation of the physical model.


-Justin

--
==

Justin A. Lemkul, Ph.D.
Postdoctoral Fellow

Department of Pharmaceutical Sciences
School of Pharmacy
Health Sciences Facility II, Room 601
University of Maryland, Baltimore
20 Penn St.
Baltimore, MD 21201

jalem...@outerbanks.umaryland.edu | (410) 706-7441

==
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[gmx-users] stopped simulation

2013-11-06 Thread Ehsan Sadeghi
Hi gmx users,

I have simulated ionomer in water solution using gromos force field. But in 
middle of simulation(after 2 ns) the simulation stopped and I received these 
messages:


WARNING: Listed nonbonded interaction between particles 174 and 188
at distance 3f which is larger than the table limit 3f nm.

This is likely either a 1,4 interaction, or a listed interaction inside
a smaller molecule you are decoupling during a free energy calculation.
Since interactions at distances beyond the table cannot be computed,
they are skipped until they are inside the table limit again. You will
only see this message once, even if it occurs for several interactions.

IMPORTANT: This should not happen in a stable simulation, so there is
probably something wrong with your system. Only change the table-extension
distance in the mdp file if you are really sure that is the reason.

Fatal error:
1 particles communicated to PME node 5 are more than 2/3 times the cut-off out 
of the domain decomposition cell of their charge group in dimension y.
This usually means that your system is not well equilibrated.



I used simulated annealing for equilibrating the system in NVT and NPT 
condition. The mdp files are: 

 NVT --

define = -DPOSRES
integrator = md 
dt = 0.002 ; time step (in ps)
nsteps = 25000 ; Maximum number of steps to perform

; OUTPUT CONTROL OPTIONS
nstxout= 500 
nstvout= 500 
nstenergy  = 500 
nstlog = 500 
energygrps = Non-Water Water

; NEIGHBORSEARCHING PARAMETERS

nstlist= 1 
ns_type= grid 
rlist  = 1.5 
pbc= xyz 

; OPTIONS FOR ELECTROSTATICS AND VDW

coulombtype= PME 
pme_order  = 4   
fourierspacing= 0.16 
rcoulomb   = 1.5 
vdw-type   = Cut-off
rvdw   = 1.5 

; Temperature coupling

tcoupl = v-rescale
tc-grps= Non-Water Water
tau_t  = 0.10.1 
ref_t  = 300300 
; Dispersion correction
DispCorr   = EnerPres 
; Pressure coupling is off
pcoupl = no 

; Annealing

annealing   = single single
annealing-npoints = 5  5
annealing-time = 0 10 20 30 40 0 10 20 30 40
annealing-temp = 300 320 340 360 380 300 320 340 360 380

; GENERATE VELOCITIES FOR STARTUP RUN
gen_vel= yes 
gen_temp   = 300 
gen_seed   = -1  

; OPTIONS FOR BONDS
constraints = ; all-bonds 
continuation= no 
constraint_algorithm = lincs 
lincs_iter = 1
lincs_order= 4   

- NPT 

define = -DPOSRES
integrator = md 
dt = 0.002 
nsteps = 25000 

; OUTPUT CONTROL OPTIONS
nstxout= 500 
nstvout= 500
nstfout= 500
nstenergy  = 500
nstlog = 500 
energygrps = Non-Water Water

; NEIGHBORSEARCHING PARAMETERS

nstlist= 5 
ns_type= grid 
rlist  = 1.5 
pbc= xyz 

; OPTIONS FOR ELECTROSTATICS AND VDW

coulombtype= PME 
pme_order  = 4  
fourierspacing= 0.16 
rcoulomb   = 1.5 
vdw-type   = Cut-off
rvdw   = 1.5 

; Temperature coupling

tcoupl = v-rescale
tc-grps= Non-Water Water
tau_t  = 0.10.1
ref_t  = 300300 
; Dispersion correction
DispCorr   = EnerPres 

pcoupl = Parrinello-Rahman
Pcoupltype = Isotropic
tau_p  = 2.0
compressibility = 4.5e-5
ref_p  = 1.0
refcoord_scaling = com 

; Annealing

annealing   = single single
annealing-npoints = 5  5
annealing-time = 0 10 20 30 40 0 10 20 30 40
annealing-temp = 380 360 340 320 300 380 360 340 320 300


; GENERATE VELOCITIES FOR STARTUP RUN
gen_vel= no

; OPTIONS FOR BONDS
constraints = ; all-bonds 
continuation= yes ;continuation from NVT
constraint_algorithm = lincs 
lincs_iter = 1
lincs_order= 4   
--

Is the equilibration time is long enough? I appreciate any help/suggestion 
regarding my case.

Kind regards,
Ehsan


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