Re: [gmx-users] shall we use double precision?

2013-06-11 Thread Albert
HI Mark: thank you for kind reply. I found the following in the documentations: Installations: Example. This is the procedure for compiling the serial version of GROMACS, using the GNU compilers. tar zxf gromacs-4.0.5.tar.gz cd gromacs-4.0.5 export plumedir="PLUMED root" cp $plumedir/patches

Re: [gmx-users] site-site Coulombic force

2013-06-11 Thread Mark Abraham
Not directly. Code that permitted doing so during the actual simulation would be far too inefficient. You can use tpbconv and trjconv to make matching subsets of your .tpr and output trajectory, and pass those through mdrun -rerun. Or, depending what you actually want, you may need to make an .mdp

Re: [gmx-users] shall we use double precision?

2013-06-11 Thread Dr. Vitaly Chaban
It is *desirable*. In many cases of free energy calculations, single precision is still reliable. Dr. Vitaly Chaban On Tue, Jun 11, 2013 at 7:35 AM, Albert wrote: > Hello : > > I am going to use Gromacs with PLUMD plugin to perform Metadynamics. > Since this methods involved in free ener

Re: [gmx-users] Angles not read

2013-06-11 Thread Steven Neumann
On Mon, Jun 10, 2013 at 1:44 PM, Justin Lemkul wrote: > > > On 6/10/13 8:42 AM, Justin Lemkul wrote: > >> >> >> On 6/10/13 8:40 AM, Steven Neumann wrote: >> >>> On Mon, Jun 10, 2013 at 1:27 PM, Justin Lemkul wrote: >>> >>> On 6/10/13 8:23 AM, Steven Neumann wrote: Dear Gmx U

[gmx-users] equilibration error

2013-06-11 Thread Souilem Safa
Dear Gromacs users, I tried to do the simulation of a single molecule in cyclohexane, I'm using gromos 53a6 force field for both molecules. i did all the minimization steps. After npt, I runned for 25 000 000 steps. just after around 100 000 steps, the system stops and i got this fatal error: Fa

[gmx-users] Constraints of distance

2013-06-11 Thread Steven Neumann
Dear Gmx Users, I am running CG simulation and I wish my beads to be constraint - one away from each other of 0.4 nm. I wan to use Lincs for this purpose. I do not have any bonds in my topology or rtp entry. I just add: [ constraints ] 1 2 1 0.4 2 3 1 0.4 ... 31 32

Re: [gmx-users] stay at some temperature during annealing

2013-06-11 Thread Justin Lemkul
On 6/11/13 1:11 AM, mu xiaojia wrote: Hi guys, I am using simulated annealing for my protein+water+Ion system, I tried to let the system stay at some temperature for a while, e.g.: stay at 600k from 3000ps to 1 ps, then gradually cool it down to 298k, so my mdp is like: annealing_time = 0

Re: [gmx-users] A charge group moved too far between two domain decomposition steps

2013-06-11 Thread Justin Lemkul
On 6/11/13 1:30 AM, Souilem Safa wrote: Dear Gromacs users, I tried to do the simulation of a single molecule in cyclohexane, I'm using gromos 53a6 force field for both molecules. i did all the minimization steps. After npt, I runned for 25 000 000 steps. just after around 100 000 steps, the

Re: [gmx-users] restraints on water oxygen atoms

2013-06-11 Thread Justin Lemkul
On 6/11/13 2:05 AM, Shima Arasteh wrote: These are the all commands to do iteration: After generating topology -concatenate the protein and bilayer structure files: #cat dimer-newbox.gro popc-whole.gro > system.gro ( Remove unnecessary lines and update the second line of the c

Re: [gmx-users] Angles not read

2013-06-11 Thread Justin Lemkul
On 6/11/13 5:59 AM, Steven Neumann wrote: On Mon, Jun 10, 2013 at 1:44 PM, Justin Lemkul wrote: On 6/10/13 8:42 AM, Justin Lemkul wrote: On 6/10/13 8:40 AM, Steven Neumann wrote: On Mon, Jun 10, 2013 at 1:27 PM, Justin Lemkul wrote: On 6/10/13 8:23 AM, Steven Neumann wrote: D

Re: [gmx-users] Constraints of distance

2013-06-11 Thread Justin Lemkul
On 6/11/13 6:30 AM, Steven Neumann wrote: Dear Gmx Users, I am running CG simulation and I wish my beads to be constraint - one away from each other of 0.4 nm. I wan to use Lincs for this purpose. I do not have any bonds in my topology or rtp entry. I just add: [ constraints ] 1 2 1

Re: [gmx-users] restraints on water oxygen atoms

2013-06-11 Thread Shima Arasteh
I put the output file of shrinking steps after 32 iterations: https://jumpshare.com/b/5Y6WUGv7OT1sOFzsrWgN   Sincerely, Shima - Original Message - From: Justin Lemkul To: Shima Arasteh ; Discussion list for GROMACS users Cc: Sent: Tuesday, June 11, 2013 3:25 PM Subject: Re: [gmx-us

Re: [gmx-users] Constraints of distance

2013-06-11 Thread Dr. Vitaly Chaban
I think all is correct. Why are you asking? People normally report problems. Dr. Vitaly Chaban On Tue, Jun 11, 2013 at 12:30 PM, Steven Neumann wrote: > Dear Gmx Users, > > I am running CG simulation and I wish my beads to be constraint - one away > from each other of 0.4 nm. I wan to use

Re: [gmx-users] A charge group moved too far between two domain decomposition steps

2013-06-11 Thread Dr. Vitaly Chaban
This problem indeed happens from time to time. With versions 4.5+ it is more frequent than with versions up to 4.0.7. It is not always connected to blowing up in the sense of bad contacts, positive potential energy, etc. The more cores you use per job, the more likely this error to appear. The larg

Re: [gmx-users] stay at some temperature during annealing

2013-06-11 Thread Dr. Vitaly Chaban
On Tue, Jun 11, 2013 at 12:52 PM, Justin Lemkul wrote: > > > On 6/11/13 1:11 AM, mu xiaojia wrote: > >> Hi guys, >> >> I am using simulated annealing for my protein+water+Ion system, I tried to >> let the system stay at some temperature for a while, e.g.: stay at 600k >> from 3000ps to 1 ps,

[gmx-users] Re: restraints on water oxygen atoms

2013-06-11 Thread JW Gibbs
Hi, As Justin had already suggested, restraints will lead to nasty atomic clashes. Looking at the gro file you have provided, it seems that the system is very poorly equilibrated. I had a similar issue. If the forcefield you are using is accurate enough, follow the steps as follows: 1. Take th

Re: [gmx-users] Re: restraints on water oxygen atoms

2013-06-11 Thread Justin Lemkul
On 6/11/13 9:38 AM, JW Gibbs wrote: Hi, As Justin had already suggested, restraints will lead to nasty atomic clashes. Looking at the gro file you have provided, it seems that the system is very poorly equilibrated. I had a similar issue. If the forcefield you are using is accurate enough, fo

Fwd: Re: [gmx-users] restraints on water oxygen atoms

2013-06-11 Thread Justin Lemkul
I was having issues with my email earlier today, so some things did not go through. Apologies if this is a multiple post, but I wanted to make sure it got through, especially since it provides resolution to a very long-running thread: On 6/11/13 7:46 AM, Shima Arasteh wrote: I put the outpu

Re: [gmx-users] A charge group moved too far between two domain decomposition steps

2013-06-11 Thread Justin Lemkul
On 6/11/13 9:27 AM, Dr. Vitaly Chaban wrote: This problem indeed happens from time to time. With versions 4.5+ it is more frequent than with versions up to 4.0.7. It is not always connected to blowing up in the sense of bad contacts, positive potential energy, etc. The more cores you use per jo

Re: [gmx-users] Constraints of distance

2013-06-11 Thread Steven Neumann
I was not sure about the fucntion type (1 or 2). Once in manual it is stated that function 1 is only for exclusions and another time it can be used to miimc bonds. Both functions are working though. Thanks anyway. Steven On Tue, Jun 11, 2013 at 2:18 PM, Dr. Vitaly Chaban wrote: > I think all i

Re: [gmx-users] A charge group moved too far between two domain decomposition steps

2013-06-11 Thread Dr. Vitaly Chaban
On Tue, Jun 11, 2013 at 3:52 PM, Justin Lemkul wrote: > > > On 6/11/13 9:27 AM, Dr. Vitaly Chaban wrote: > >> This problem indeed happens from time to time. With versions 4.5+ it is >> more frequent than with versions up to 4.0.7. It is not always connected >> to >> blowing up in the sense of bad

Re: [gmx-users] Constraints of distance

2013-06-11 Thread Dr. Vitaly Chaban
Steven - I probably know nothing about "function #2", but "function 1" is used just everywhere. It does constrain intramolecular distances. Good luck. Vitaly Dr. Vitaly Chaban On Tue, Jun 11, 2013 at 4:46 PM, Steven Neumann wrote: > I was not sure about the fucntion type (1 or 2). Once in ma

[gmx-users] Membrane Equilibration

2013-06-11 Thread Neha
Hi everybody, I am trying to simulate a lipid bilayer and wanted to use Parrinello Rahman coupling. However, I read that Parinello-Rahman is not great for equilibration so I thought I would do a small run using the Berendsen barostat to decrease the chances of large oscillations. I then used the .

Re: [gmx-users] Membrane Equilibration

2013-06-11 Thread Dr. Vitaly Chaban
what happens to your energy before the observed crash? does the crash happen at the same time-step each time? Dr. Vitaly Chaban On Tue, Jun 11, 2013 at 5:22 PM, Neha wrote: > Hi everybody, > > I am trying to simulate a lipid bilayer and wanted to use Parrinello Rahman > coupling. However, I r

Re: [gmx-users] Constraints of distance

2013-06-11 Thread Justin Lemkul
On 6/11/13 10:46 AM, Steven Neumann wrote: I was not sure about the fucntion type (1 or 2). Once in manual it is stated that function 1 is only for exclusions and another time it can be used to miimc bonds. Both functions are working though. Thanks anyway. More precisely, constraints of typ

Re: [gmx-users] Membrane Equilibration

2013-06-11 Thread HANNIBAL LECTER
ref_p= 0.0 0.0 ?? Are you sure about this?? On Tue, Jun 11, 2013 at 12:08 PM, Dr. Vitaly Chaban wrote: > what happens to your energy before the observed crash? does the crash > happen at the same time-step each time? > > > Dr. Vitaly Chaban > > > On Tue, Jun 11, 2013 at 5:2

Re: [gmx-users] A charge group moved too far between two domain decomposition steps

2013-06-11 Thread Justin Lemkul
On 6/11/13 10:55 AM, Dr. Vitaly Chaban wrote: On Tue, Jun 11, 2013 at 3:52 PM, Justin Lemkul mailto:jalem...@vt.edu>> wrote: On 6/11/13 9:27 AM, Dr. Vitaly Chaban wrote: This problem indeed happens from time to time. With versions 4.5+ it is more frequent than with ve

Re: [gmx-users] Membrane Equilibration

2013-06-11 Thread Justin Lemkul
On 6/11/13 1:13 PM, HANNIBAL LECTER wrote: ref_p= 0.0 0.0 ?? Are you sure about this?? That's a likely culprit. See below for another. On Tue, Jun 11, 2013 at 12:08 PM, Dr. Vitaly Chaban wrote: what happens to your energy before the observed crash? does the crash

[gmx-users] Re: Membrane Equilibration

2013-06-11 Thread Neha
Hi everybody, Thank you so much for taking the time to read this. I thought ref_p would need to be 0.0 and 0.0 if I wanted zero surface tension. How else could I get a tensionless membrane? As for the generating velocities, I completely forgot that would ruin the equilibrium. Would you recommend

[gmx-users] Re: Membrane Equilibration

2013-06-11 Thread JW Gibbs
Exactly so. I think Gromacs issues a warning when you try to initialize velocities with Parrinello-Rahman barostat. But if you performed your equilibration at 105K using Berendsen barostat, I think it should be okay and you should put gen-vel = no. -- View this message in context: http://groma

Re: [gmx-users] Re: Membrane Equilibration

2013-06-11 Thread Justin Lemkul
On 6/11/13 1:25 PM, Neha wrote: Hi everybody, Thank you so much for taking the time to read this. I thought ref_p would need to be 0.0 and 0.0 if I wanted zero surface tension. How else could I get a tensionless membrane? As far as I understand, surface tension is only applied when using "p

[gmx-users] Re: Membrane Equilibration

2013-06-11 Thread JW Gibbs
Is there a reason you would like to keep it at 105K? Just curious which forcefield are you using? Also, for proper surface tension, there is an option called pcoupltype = surface-tension. I think you should check that out. -- View this message in context: http://gromacs.5086.x6.nabble.co

[gmx-users] Re: Membrane Equilibration

2013-06-11 Thread Neha
Hi, I am using the Martini field for those who wanted to know. My values for the mdp file for ref_p were inspired from this paper as it says pressure was coupled anisotropically to 0 bar in all directions. http://www.sciencedirect.com/science/article/pii/S0005273611002045 I think I will try to

[gmx-users] System does not heat up to 300K.

2013-06-11 Thread Marc Hömberger
Hi, I have a system setup (minimized etc.) and wanted to heat this system gradually with simulated annealing. I set up the mdp file as you can see below (simulated annealing part is marked bold). But when the heating is finished, the log file tells me that the temperature of the system is only 1K

[gmx-users] Enthalpy Confusion

2013-06-11 Thread Jeffery Perkins
This may just be me not understanding what I'm looking at, but I'm trying to get the Enthalpy of a simple test system of LJ fluid, running version 4.5.4 initially I've tried using the enthalpy option in g_energy but I noticed that if i compare that value to H=U+pV using either the average or the i

Re: [gmx-users] System does not heat up to 300K.

2013-06-11 Thread Justin Lemkul
On 6/11/13 2:07 PM, Marc Hömberger wrote: Hi, I have a system setup (minimized etc.) and wanted to heat this system gradually with simulated annealing. I set up the mdp file as you can see below (simulated annealing part is marked bold). But when the heating is finished, the log file tells me

Re: [gmx-users] System does not heat up to 300K.

2013-06-11 Thread Dr. Vitaly Chaban
According to your MD parameters, your system should attain T=300K at the 300th nanosecond. Since you have run only for 50 * 0.002 ps = 1ns, you got T=1K, since temperature elevates linearly, based on your setup. Dr. Vitaly Chaban On Tue, Jun 11, 2013 at 8:07 PM, Marc Hömberger wrote: >

Re: [gmx-users] System does not heat up to 300K.

2013-06-11 Thread Marc Hoemberger
Thanks, I must have confused the units for the simulated annealing parameters. On Tue, Jun 11, 2013 at 2:12 PM, Dr. Vitaly Chaban wrote: > According to your MD parameters, your system should attain T=300K at the > 300th > nanosecond. > > Since you have run only for 50 * 0.002 ps = 1ns, you g

Re: [gmx-users] Enthalpy Confusion

2013-06-11 Thread David van der Spoel
On 2013-06-11 20:09, Jeffery Perkins wrote: This may just be me not understanding what I'm looking at, but I'm trying to get the Enthalpy of a simple test system of LJ fluid, running version 4.5.4 initially I've tried using the enthalpy option in g_energy but I noticed that if i compare that valu

[gmx-users] Re: Enthalpy Confusion

2013-06-11 Thread Jeffery Perkins
that's what i thought, and what i tried to do, my pressure is a bit higher then that, we want a Lennard-Jones liquid so it's running at 1000+ bar, and while I agree that gromacs is giving H as Etot + pV it appears that when i calculate pV i get a different value from what g_energy returns for it I

Re: [gmx-users] Re: Enthalpy Confusion

2013-06-11 Thread Michael Shirts
If you are computing enthaply in the NPT ensemble, P is constant, and is the applied pressure. The "pressure" quantity calculated from the KE and the virial is not the pressure. It is a quantity that when averaged over time is equal the pressure. Only the average is meaningful macroscopically.

[gmx-users] 2013 GROMACS USA Workshop and Conference

2013-06-11 Thread Michael Shirts
Dear GROMACS users list members: We are pleased to announce the 2013 GROMACS USA Workshop and Conference at the University of Virginia in Charlottesville, Virginia, on September 13-15th. This will be the first full GROMACS workshop held here in the U.S. The workshop and conference will consist o

Re: [gmx-users] Constraints of distance

2013-06-11 Thread Steven Neumann
Thank you Justin. So using nrexcl 0 or 1 (should be the same with constraints) and type 1 will allow bonded atoms to interact (vdW) with each other? On Tue, Jun 11, 2013 at 6:10 PM, Justin Lemkul wrote: > > > On 6/11/13 10:46 AM, Steven Neumann wrote: > >> I was not sure about the fucntion type

[gmx-users] Re: Enthalpy Confusion

2013-06-11 Thread Jeffery Perkins
>If you are computing enthaply in the NPT ensemble, P is constant, and >is the applied pressure. >The "pressure" quantity calculated from the KE and the virial is not >the pressure. It is a quantity that when averaged over time is equal >the pressure. Only the average is meaningful macroscop

[gmx-users] [ defaults ] and nonbonded

2013-06-11 Thread Steven Neumann
Dear Gromacs Users, I got really confused: In manual [defualts ]: "nbfunc is the non-bonded function type. Use 1 (Lennard-Jones) or 2 (Buckingham)" I want to use mdrun -table table.xvg with my own potential, which one I should choose? "gen-pairs - is for pair generation. The default is ‘no’, i.

Re: [gmx-users] Re: Enthalpy Confusion

2013-06-11 Thread David van der Spoel
On 2013-06-11 21:57, Jeffery Perkins wrote: If you are computing enthaply in the NPT ensemble, P is constant, and is the applied pressure. The "pressure" quantity calculated from the KE and the virial is not the pressure. It is a quantity that when averaged over time is equal the pressure. O

[gmx-users] Re: Enthalpy Confusion

2013-06-11 Thread Jeffery Perkins
>You should not use pV from g_energy though, as Michael explained, rather >you need ref_p times . This precludes that your system is in >equilibrium of course. That is what I had initially thought, then take that with the to get ? or should i be doing < U+*ref_p > = ? But even so I still get d

Re: [gmx-users] Re: Enthalpy Confusion

2013-06-11 Thread Michael Shirts
> or should i be doing < U+*ref_p > = ? More specifically, + *ref_p = H isn't really meaningful thing. I mean, you can define something such that = H, but that's not really thermodynamics. > example system gives = -1168 kJ/mol and i find = -725 kJ/mol either Interesting. What material at

Re: [gmx-users] Re: mdrun segmentation fault for new build of gromacs 4.6.1

2013-06-11 Thread Szilárd Páll
Hi Amil, On Mon, Jun 10, 2013 at 11:03 PM, Amil Anderson wrote: > Szilárd, > > I tried the build using a PATH without the Intel compilers and NOT including > the directives -DGMX_EXTERNAL_BLAS=OFF and -DGMX_EXTERNAL_LAPACK=OFF and it > used the FFTW 3.2 wrappers to MKL. Here is the output fro

[gmx-users] Re: Enthalpy Confusion

2013-06-11 Thread Jeffery Perkins
> >or should i be doing < U+*ref_p > = ? >More specifically, + *ref_p = H > isn't really meaningful thing. I mean, you can define something >such that = H, but that's not really thermodynamics. sorry I always have issues deciding how to talk about this stuff, so thanks for putting up with

Aw: [gmx-users] Enthalpy Confusion

2013-06-11 Thread lloyd riggs
If you only want the total for the system or a delta for an entire run, indexed group there of, covarience (covar/aneig) does a good job.  I found neither actually fit, but the covarience does, or if you do it by hand using only LJ parmeters for the indexed sets, however I was using proteins, so f

[gmx-users] Re: gromacs 4.6.2 MPI distribution location problems

2013-06-11 Thread sirishkaushik
Note that this works fine with 4.5.5. when I installed using: ./configure CPPFLAGS="-I/home/kaushik/fftw-new/include" LDFLAGS="-L/home/kaushik/fftw-new/lib" --enable-mpi --prefix /home/kaushik/gromacs_executable/gromacs-old ldd mdrun on the 4.5.5 version correctly points to the fftw and the mpi

Re: [gmx-users] [ defaults ] and nonbonded

2013-06-11 Thread Justin Lemkul
On 6/11/13 4:12 PM, Steven Neumann wrote: Dear Gromacs Users, I got really confused: In manual [defualts ]: "nbfunc is the non-bonded function type. Use 1 (Lennard-Jones) or 2 (Buckingham)" I want to use mdrun -table table.xvg with my own potential, which one I should choose? "gen-pairs - i

Re: [gmx-users] Constraints of distance

2013-06-11 Thread Justin Lemkul
On 6/11/13 3:47 PM, Steven Neumann wrote: Thank you Justin. So using nrexcl 0 or 1 (should be the same with constraints) and type 1 will allow bonded atoms to interact (vdW) with each other? No, there will be differences for type 1 in this case. Type 1 generates exclusions per nrexcl. Usi

[gmx-users] Re: Genbox center of box

2013-06-11 Thread Matt Bawn
OK I found the problem. I had installed Surfnet the protein cavity finder a few weeks ago, and it turns out this also has a function called genbox! so my silly mistake. I was wondering why centre and not center. Thanks, Matt On Mon, Jun 10, 2013 at 6:23 PM, Justin Lemkul [via GROMACS] < ml-

[gmx-users] Re: distance_restraints

2013-06-11 Thread maggin
Hi, Justin, You are right, I should first fix the bad geometry. I check 1dx0.pdb, and the problematic areas are: atom1 atom2 1 N1+ (GLY124 N) 4 H (GLY124 HT3) 181 C (PRO137 CD)182 H (PRO137 HD1) 262 H (PHE14