Re: [gmx-users] Cannot find gmx_mpi when installing gromacs 5.0

2014-08-28 Thread Mark Abraham
I'd guess your permissions on some part of
/users/yli/gromacs-5.0/exec/bin/gmx_mpi
are such that you can't access.

Mark


On Thu, Aug 28, 2014 at 4:06 AM, 朱文鹏 jasonzhu...@gmail.com wrote:

 Dear all,

 I am trying to install gromacs 5.0 by cmake on my cluster. But an error
 occurs when I make install.

 The module list for environment is given as below:
 mvapich2/2.0rc1-intel
 cmake/2.8.12.2
 intel/2013.1.106
 fftw/3.3.2

 And the sequence of commands to execute is:
 ---
 cmake ../ \
 -DCMAKE_C_COMPILER=mpicc \
 -DCMAKE_CXX_COMPILER=mpicxx \
 -DGMX_X11=OFF \
 -DGMX_MPI=ON \
 -DCMAKE_INSTALL_PREFIX=/users/yli/gromacs-5.0/exec \
 -DCMAKE_INCLUDE_PATH=/gpfs/runtime/opt/fftw/3.3.2/include \
 -DCMAKE_LIBRARY_PATH=/gpfs/runtime/opt/fftw/3.3.2/lib/libfftw3f.a

 make

 make install
 ---

 Configuration and make finished successfully. There are no errors or
 warnings on the first two steps. However, an error shows up at the final
 step of make install as below:
 ---
 ..
 -- Up-to-date:

 /users/yli/gromacs-5.0/exec/include/gromacs/trajectoryanalysis/analysismodule.h
 -- Up-to-date:

 /users/yli/gromacs-5.0/exec/include/gromacs/trajectoryanalysis/analysissettings.h
 -- Up-to-date:

 /users/yli/gromacs-5.0/exec/include/gromacs/trajectoryanalysis/cmdlinerunner.h
 CMake Error at src/programs/cmake_install.cmake:42 (FILE):
   file INSTALL cannot find /users/yli/gromacs-5.0/exec/bin/gmx_mpi.
 Call Stack (most recent call first):
   src/cmake_install.cmake:40 (INCLUDE)
   cmake_install.cmake:49 (INCLUDE)


 make: *** [install] Error 1
 ---

 And the executable file gmx_mpi cannot be found anywhere. It is the first
 time I install the version 5.0. The same installation and environments work
 for the version 4.6.5. I am wondering if anyone has the same problems when
 installing gromacs 5.0. I would appreciate it if you have any suggestion to
 my installation.

 Thank you very much.

 Best,
 Jason
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Re: [gmx-users] md simulation steps

2014-08-28 Thread Mark Abraham
No :-)

It depends what you are trying to observe; generally that's statistical in
nature and you thus need to make a large number of independent
post-equilibration observations from a converged trajectory. Doing that is
generally quite difficult - you should be guided by what previous people
have done in similar work.

Mark


On Thu, Aug 28, 2014 at 7:34 AM, Meenakshi Rajput ashi.rajpu...@gmail.com
wrote:

 hello
 Can you tell me how many steps are sufficient for md simulation of
 protein-ligand complex?
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[gmx-users] water not getting settle

2014-08-28 Thread Lovika Moudgil
Hi everyone ,

I am getting an error about water i.e

step 168: Water molecule starting at atom 5226 can not be settled.
Check for bad contacts and/or reduce the timestep if appropriate.

I have already tried reducing timestep ..but it didn't worked . If I freeze
water things work fine . But what if I do not want to freeze it !! What is
the other way to get it settled ?

Thanks and Regards
Lovika
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Re: [gmx-users] water not getting settle

2014-08-28 Thread Mark Abraham
Depends what the problem really is. See strategies at
http://www.gromacs.org/Documentation/Terminology/Blowing_Up

Mark


On Thu, Aug 28, 2014 at 9:35 AM, Lovika Moudgil lovikamoud...@gmail.com
wrote:

 Hi everyone ,

 I am getting an error about water i.e

 step 168: Water molecule starting at atom 5226 can not be settled.
 Check for bad contacts and/or reduce the timestep if appropriate.

 I have already tried reducing timestep ..but it didn't worked . If I freeze
 water things work fine . But what if I do not want to freeze it !! What is
 the other way to get it settled ?

 Thanks and Regards
 Lovika
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Re: [gmx-users] Time varying electric field - phase term

2014-08-28 Thread Johnny Lu
Or, can you wait a while before you turn on the field?

So far, I know that people can do npt after nvt.
Can you run simulation without field, then, with field?
Just have to count the delays.

There might be some truncation effect tough if you turn on the field
suddenly.


On Wed, Aug 27, 2014 at 3:25 PM, steven shawn shawnstev...@gmail.com
wrote:

 Thanks for your reply Johnny Lu. That is a very good point. But I have not
 seen any sin Electric field. Can gromacs generate sin Electric fields too?


 On Tue, Aug 26, 2014 at 8:33 PM, Johnny Lu johnny.lu...@gmail.com wrote:

  I wonder if gromacs can do both sine and cosine?
 
  If so, the sum angle formula can work.
 
 
 
 http://en.wikipedia.org/wiki/List_of_trigonometric_identities#Angle_sum_and_difference_identities
 
 
 
  On Sat, Aug 23, 2014 at 10:42 AM, steven shawn shawnstev...@gmail.com
  wrote:
 
   Dear gromacs users, I am trying to use an electric field which is
 varying
   with time. I read the previous posts and successfully generated time
   varying electric field with E-xt, E-yt and E-zt.
  
   but I need an electric field which has an initial phase term (ie. of
 the
   form E= E0cos(2*pi*f*t+some angle term)) where i want to specify the
  angle
   term. Most of the posts i read mentioned this angle term must be
  specified
   in the third term after E-xt.
   I tried it but failed to generate an initial phase. Can anyone help me
  with
   this?
  
  
   thanks in advance.
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[gmx-users] MD exit condition

2014-08-28 Thread Eric Smoll
Hello Gromacs users,

I am using Gromacs 4.6.5

Is there a way to set an exit condition during a simulation? I am
interested in terminating dynamics when two groups are separated by a
certain distance.

If it is not possible to set an exit condition, I suspect I can post
process the trajectory with trjconv using the -exec flag and/or the -trunc
flag:

1.) The manual states that the -exec flag will Execute a command for every
output frame with the frame number as argument. What kinds of commands I
can pass to this flag?

2.) If the -exec is not useful, I plan to analyse the the output of
g_dist to find the the time t when two groups exceed my distance
criterion and run trjconv -trunc t to crop the trajectory appropriately.
Is there a better way?

Best,
Eric
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Re: [gmx-users] Cannot find gmx_mpi when installing gromacs 5.0

2014-08-28 Thread 朱文鹏
Dear Mark,

Thank you for your response. But I can install gromacs 4.6.5 successfully
with the same permission.

I will still contact the administrator of the cluster. Do you have idea
what permissions I should ask them for if I need to install 5.0? Any files
or directories, or any permissions to execute files?

I don't think it is good for gromacs installation to access some parts
needing higher permissions. After all, most of users who need to install
gromacs onto cluster are not administrators.

Best,
Jason


Date: Thu, 28 Aug 2014 08:45:40 +0200
From: Mark Abraham mark.j.abra...@gmail.com
To: Discussion list for GROMACS users gmx-us...@gromacs.org
Subject: Re: [gmx-users] Cannot find gmx_mpi when installing gromacs
5.0
Message-ID:
camnumaqmqgkjdl7rgzfm4ua4ovxspo5r98evumm5zucp1oj...@mail.gmail.com
Content-Type: text/plain; charset=UTF-8

I'd guess your permissions on some part of
/users/yli/gromacs-5.0/exec/bin/gmx_mpi
are such that you can't access.

Mark


On Thu, Aug 28, 2014 at 4:06 AM, ??? jasonzhu...@gmail.com wrote:

 Dear all,

 I am trying to install gromacs 5.0 by cmake on my cluster. But an error
 occurs when I make install.

 The module list for environment is given as below:
 mvapich2/2.0rc1-intel
 cmake/2.8.12.2
 intel/2013.1.106
 fftw/3.3.2

 And the sequence of commands to execute is:
 ---
 cmake ../ \
 -DCMAKE_C_COMPILER=mpicc \
 -DCMAKE_CXX_COMPILER=mpicxx \
 -DGMX_X11=OFF \
 -DGMX_MPI=ON \
 -DCMAKE_INSTALL_PREFIX=/users/yli/gromacs-5.0/exec \
 -DCMAKE_INCLUDE_PATH=/gpfs/runtime/opt/fftw/3.3.2/include \
 -DCMAKE_LIBRARY_PATH=/gpfs/runtime/opt/fftw/3.3.2/lib/libfftw3f.a

 make

 make install
 ---

 Configuration and make finished successfully. There are no errors or
 warnings on the first two steps. However, an error shows up at the final
 step of make install as below:
 ---
 ..
 -- Up-to-date:

 /users/yli/gromacs-5.0/exec/include/gromacs/trajectoryanalysis/
analysismodule.h
 -- Up-to-date:

 /users/yli/gromacs-5.0/exec/include/gromacs/trajectoryanalysis/
analysissettings.h
 -- Up-to-date:

 /users/yli/gromacs-5.0/exec/include/gromacs/trajectoryanalysis/
cmdlinerunner.h
 CMake Error at src/programs/cmake_install.cmake:42 (FILE):
   file INSTALL cannot find /users/yli/gromacs-5.0/exec/bin/gmx_mpi.
 Call Stack (most recent call first):
   src/cmake_install.cmake:40 (INCLUDE)
   cmake_install.cmake:49 (INCLUDE)


 make: *** [install] Error 1
 ---

 And the executable file gmx_mpi cannot be found anywhere. It is the
first
 time I install the version 5.0. The same installation and environments
work
 for the version 4.6.5. I am wondering if anyone has the same problems when
 installing gromacs 5.0. I would appreciate it if you have any suggestion
to
 my installation.

 Thank you very much.

 Best,
 Jason
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[gmx-users] GB parameters for DNA

2014-08-28 Thread Jianguo Li
Dear everyone,

I would like to simulate a DNA-protein complex using implicit solvent model. 
Anyone has the GB parameters for phosphorus atom?  I searched the mailing list, 
but did not find the answer.

Thanks in advance

Cheers,
Jianguo 
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[gmx-users] Positive Potential Energy.

2014-08-28 Thread Dan Sponseller
Hello everyone.

I am still fairly new to gromcs but I have researched this well.

I am getting a positive potential energy (my bond energy is always positive) no 
matter how long I run my simulation. I also get this when doing minimizations. 
Even just one molecule set at know minimum conformation. 

I am running in vacuo with no pbc. I have read on the mail list that in vacuo 
can produce this? This doesn’t make sense as the molecule should fly apart with 
always positive PE.

I have tried gromos ff and opsla ff. Both do this. A colleague of mine also  
gets this with his simulations although he reports negative potential when 
solvated.

Any help would be appreciated or any explanation on how to interpret gromacs 
output on this.

I would question gromacs’ abilities if it cannot give a reasonable potential 
energy for a simple system.

Daniel Sponseller
PhD student
George Mason University
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[gmx-users] Surface tension for membrane simulation

2014-08-28 Thread Xiang Ning
Hi all,

I have a question of surface tension in membrane simulation. I found that in 
equilibration and production step, the pressure set up for membrane simulation 
is below:

; Pressure coupling is on
pcoupl          = Parrinello-Rahman         ; Pressure coupling on in NPT
pcoupltype      = semiisotropic             ; uniform scaling of x-y box 
vectors, independent z
tau_p           = 2.0                           ; time constant, in ps
ref_p           = 1.0   1.0                     ; reference pressure, x-y, z 
(in bar)
compressibility = 4.5e-5        4.5e-5  ; isothermal compressibility, bar^-1
 
I would like to know, during these steps, do we have constant pressure or 
constant surface tension? Moreover, different membrane have different surface 
tension, do we need to change and write it in the mdp file (ref_p value?) to 
run the simulation? 

Thanks a lot for your assistance! 

Best,
Ning
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Re: [gmx-users] Positive Potential Energy.

2014-08-28 Thread Justin Lemkul



On 8/28/14, 2:04 PM, Dan Sponseller wrote:

Hello everyone.

I am still fairly new to gromcs but I have researched this well.

I am getting a positive potential energy (my bond energy is always positive) no 
matter how long I run my simulation. I also get this when doing minimizations. 
Even just one molecule set at know minimum conformation.



Bond energy can only ever be zero (all bonds at exactly equilibrium values) or 
positive (not equilibrium values).



I am running in vacuo with no pbc. I have read on the mail list that in vacuo 
can produce this? This doesn’t make sense as the molecule should fly apart with 
always positive PE.

I have tried gromos ff and opsla ff. Both do this. A colleague of mine also  
gets this with his simulations although he reports negative potential when 
solvated.



Negative potentials in condensed phase systems occur because of the massive 
amount of favorable nonbonded interactions, particularly hydrogen bonding 
between waters and with solute.



Any help would be appreciated or any explanation on how to interpret gromacs 
output on this.

I would question gromacs’ abilities if it cannot give a reasonable potential 
energy for a simple system.


What is the system?  Positive energy is indeed reasonable in vacuo.

-Justin

--
==

Justin A. Lemkul, Ph.D.
Ruth L. Kirschstein NRSA 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
http://mackerell.umaryland.edu/~jalemkul

==
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Re: [gmx-users] Positive Potential Energy.

2014-08-28 Thread Tsjerk Wassenaar
Hey Daniel :)


This doesn’t make sense as the molecule should fly apart with always
 positive PE.


You need a force to make things fly apart, but the force has little to do
with the absolute PE. It's the gradients that do it. And as Justin points
out, your system can choose between positive PE and even more positive PE.

Cheers,

Tsjerk


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Tsjerk A. Wassenaar, Ph.D.
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[gmx-users] GPU Acceleration in case of Implicit Solvent Simulations

2014-08-28 Thread Siva Dasetty
Dear all,

Can we use periodic boundary conditions in case of implicit solvent
simulations? If so, why?
Also, can implicit solvent model in gromacs in any version (till 5.0) be
implemented in more than 2 processors or can it at least use GPU
acceleration provided by gromacs?

I have tried using pbc=no and group cut-off scheme in gpu based gromacs
V5.0, but there is a warning which says GPU is disabled because it
effectively works only with verlet cut-off scheme and verlet cut-off scheme
requires pbc=xyz or xy.

Also tried implementing in gromacs version 4.5.5 using openMM after
following the installation instructions in the following link, (
http://www.gromacs.org/Documentation/Installation_Instructions_4.5/GROMACS-OpenMM)
and here again there is no luck as we dont have the compatible hardware.

Thanks,
Siva
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[gmx-users] Martini force field for inhibitors

2014-08-28 Thread Sridhar Kumar Kannam
Dear Gromacs users,

I have very recently started working with  Gromacs and Martini force field.
I am able to generate the coarse-grained model for HIV Protease (1hvr.pdb).
I want to simulate the protein along with its inhibitor. Are there any
guidelines for building (coarse-graining) its inhibitor ?

Sorry for the naive question ...

Thank you.






-- 
Cheers !!!
Sridhar  Kumar Kannam :)
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[gmx-users] g_select syntax

2014-08-28 Thread Bin Liu
Hi Everyone,

I am recently puzzled by the syntax and behaviour of g_select. I want to
obtain the residue index list of LIPID whose center of mass is within 1.0
nm of the surface of protein. In my case, each LIPID molecule consists of
only one residue. I wrote the selection.dat as follows, and set -selrpos to
atom and -seltype to res_com. Here I think Protein is the reference
group, so -selrpos should be atom because I care about the distance to its
surface. LIPID is the analysis group and I care about their individual
center of mass. So -seltype should be res_com.

selection.dat:
resname LIPID and within 1.0 of group Protein;

g_select -sf selection.dat -f traj.trr -s traj.tpr -n system.ndx  -oi
index.dat -seltype res_com -selrpos atom



However I tried another selection. This time instead of retrieving the
residue index, I tried to retrieve the index of a key atom of the LIPID
molecule.
selection.dat:
rdist = res_com within 1.0 of group Protein;
group_C15 = (resname LIPID) and (rdist) and (name C15);
group_C15;

g_select -sf selection.dat -f traj.trr -s traj.tpr -n system.ndx  -oi
index.dat -seltype atom -selrpos atom

I thought these two selections should give the same number of indices per
frame, as the second selection merely retrieve the atom indices of the
corresponding key atoms in the LIPID molecules selected by the first
selection. However the first selection gives significantly more indices
than the second selection does. I guess my understanding of g_select syntax
might be flawed. Please point out my misunderstanding. Thank you very much.

Best Regards,

Bin
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[gmx-users] Water droplet moving away from surface

2014-08-28 Thread Kester Wong
Dear all,I am running an equilibration calculation using a new force field (GRAPPA), for a 10,000 water molecules on graphene. The run is up to 378 ps now. Iam concerned that the water droplet will drift away from the surface, rather than forming a nice droplet.Is the cutoff values in my equilibration setup appropriate for this water/graphene in vacuum?I have shared the link to the XTC, PDB, and MDP files for my run.https://drive.google.com/file/d/0B7ym8d6G9-e2eUJQMDFLTlBBZ1U/edit?usp=sharingRegards,Kester
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