Re: [gmx-users] Calculating diffusion coefficient in three dimension

2013-11-12 Thread Dr. Vitaly Chaban
MSD is 3D by default. Dr. Vitaly V. Chaban On Tue, Nov 12, 2013 at 6:01 AM, Venkat Reddy venkat...@gmail.com wrote: Dear all, I am simulating a spherical lipid vesicle. I want to calculate the diffusion coefficient for each lipid component in 3D. How to calculate it using g_msd (or any

Re: [gmx-users] Re: Reaction field zero and ions

2013-11-12 Thread Dr. Vitaly Chaban
There are no problems to have ions while using Reaction-Field treatment. Dr. Vitaly V. Chaban On Mon, Nov 11, 2013 at 7:06 PM, Justin Lemkul jalem...@vt.edu wrote: On 11/11/13 12:08 PM, Williams Ernesto Miranda Delgado wrote: Hello If I did the MD simulation using PME and neutralized

Re: [gmx-users] Charges in vacuum simulation

2013-10-28 Thread Dr. Vitaly Chaban
If in vacuum, I would add hydrogens via covalent bonds. Dr. Vitaly V. Chaban On Mon, Oct 28, 2013 at 10:29 AM, Richa Singh richa.s.rathor...@gmail.com wrote: Hi all, I'm trying to run a vacuum simulation of my protein which has a non-zero charge. How to deal with this charge? Can I add

Re: [gmx-users] Box size increases in NPT

2013-10-23 Thread Dr. Vitaly Chaban
If the job is not very parallel, it will not crash. It is better to preequilibrate in NVT beforehand. Cyclopropylchloride is probably a liquid at 290K, if the model is parametrized reasonably. So it should not phase-separate. Vitaly On Wed, Oct 23, 2013 at 11:29 AM, Mark Abraham

Re: [gmx-users] carbon nanotube - ifnite in length ?

2013-09-26 Thread Dr. Vitaly Chaban
I think this is in topology, not in MDP. With PBC, you just specify what happens to the particle after it crosses the edge of the box in certain direction. I have no preference regarding LINCS vs harmonic bonds. You can also freeze only the rim atoms of the nanotube from both ends and this will

Re: [gmx-users] trjcat after trjconv

2013-09-26 Thread Dr. Vitaly Chaban
I do not think that I ever tried myself, but is seems all the same. Why do you ask? Dr. Vitaly V. Chaban On Thu, Sep 26, 2013 at 3:40 PM, Venkat Reddy venkat...@gmail.com wrote: Dear all, I have a basic doubt. Is there any difference between the two processes where 1) I concatenate the

Re: [gmx-users] carbon nanotube - ifnite in length ?

2013-09-26 Thread Dr. Vitaly Chaban
I am just curious why the system would explode without periodic_molecules = yes. If the PBC procedure is applied before harmonic bond potential is calculated, than the opposite nanotube atoms should be (already) seen as neighboring. This looks the same as the solvent molecule, one atom of which

Re: [gmx-users] Preprocessor statements

2013-09-26 Thread Dr. Vitaly Chaban
Unlikely possible... But yeah, the feature might be handy. Dr. Vitaly V. Chaban On Thu, Sep 26, 2013 at 4:20 PM, grita cemilyi...@arcor.de wrote: Hi guys, Is it possible to specify in the topol.top file preprocessor statements, so that you can stop the simulation prematurely? I pull two

Re: [gmx-users] carbon nanotube - ifnite in length ?

2013-09-26 Thread Dr. Vitaly Chaban
restraints between nanotube atom and first atom of my chain or again - LINCS? Both chain and nanotube are made of the same type of 8 type of atoms. Please, advise. Steven On Thu, Sep 26, 2013 at 3:19 PM, Dr. Vitaly Chaban vvcha...@gmail.com wrote: I am just curious why the system would explode

Re: [gmx-users] Calculation of binding enthalpy in vacuum

2013-09-23 Thread Dr. Vitaly Chaban
Dear John - I think you can achieve the goal even faster if you just define two groups, such as MOL1 and MOL2 in MDP and then see the interaction energy between them using g_energy. 5% is a decent agreement. Usually, even basis set superposition error is larger (if you include this correction).

Re: [gmx-users] Funky output trajectory (lines all over the place)

2013-09-23 Thread Dr. Vitaly Chaban
Dear Jonathan - Is it not a PBC effect? Try to display atoms as spheres - it will look better. Otherwise, use the options in trjconv to remove PBC in the visualized structure(s). Dr. Vitaly V. Chaban On Mon, Sep 23, 2013 at 9:22 AM, Jonathan Saboury jsab...@gmail.com wrote: I tried minimizing

Re: [gmx-users] script to convert the TIP3P water model into TIP4P

2013-09-23 Thread Dr. Vitaly Chaban
I am confused. Why do you want 4-sites water? Dr. Vitaly V. Chaban On Mon, Sep 23, 2013 at 10:36 AM, ABEL Stephane 175950 stephane.a...@cea.fr wrote: Hello all, It is not a gromacs problem per se, but I hope that some gromacs users can help me. I would to do simulations of phospholipid

[gmx-users] trjconv and Floating point exception

2013-09-23 Thread Dr. Vitaly Chaban
Using trjconv -f traj.xtc -o confout.gro -dump 1500, I routinely get the following error: Select a group: 0 Selected 0: 'System' Reading frame 0 time0.000 Precision of traj.xtc is 0.004 (nm) Using output precision of 0.001 (nm) Back Off! I just backed up confout.gro to

Re: [gmx-users] Re: Re: Calculation of binding enthalpy in vacuum

2013-09-23 Thread Dr. Vitaly Chaban
On Mon, Sep 23, 2013 at 2:40 PM, Jong Wha Lee jongwh...@postech.ac.kr wrote: Dear Vitaly, Thank you for your suggestion. I have also tried calculating interaction energies by specifying energygrps in .mdp file, but calculated energies deviate greatly from QM calculated energies and

Re: [gmx-users] trjconv and Floating point exception

2013-09-23 Thread Dr. Vitaly Chaban
Dr. Vitaly V. Chaban On Mon, Sep 23, 2013 at 2:10 PM, Justin Lemkul jalem...@vt.edu wrote: On 9/23/13 6:41 AM, Dr. Vitaly Chaban wrote: Using trjconv -f traj.xtc -o confout.gro -dump 1500, I routinely get the following error: Select a group: 0 Selected 0: 'System' Reading frame

Re: [gmx-users] Constraining a part of the system

2013-09-17 Thread Dr. Vitaly Chaban
the smart way is to constrain everything at once in MDP... Dr. Vitaly V. Chaban On Tue, Sep 17, 2013 at 10:50 PM, HANNIBAL LECTER hanniballecte...@gmail.com wrote: Is there a smart way of writing the constraint sections in the topology file other than entering the values manually ? On Tue,

Re: [gmx-users] identical results or exactly the same results?

2013-09-15 Thread Dr. Vitaly Chaban
The [numerical] results will depend on architecture you are running on. No matter where the binary input file was prepared. Dr. Vitaly V. Chaban On Sun, Sep 15, 2013 at 10:22 AM, Albert mailmd2...@gmail.com wrote: Hello: I've got a md.tpr file generated by grompp, I am just wondering

Re: [gmx-users] Number Density

2013-09-15 Thread Dr. Vitaly Chaban
I would guess that the density is zero at the center, since you do not have solvent molecules inside the membrane. Yes, the output density is number of interaction sites per nm^3, calculated in each slice, whose size you had specified. Dr. Vitaly V. Chaban On Sun, Sep 15, 2013 at 5:23 PM, Sun

Re: Fwd: [gmx-users] SD integrator

2013-09-15 Thread Dr. Vitaly Chaban
file. I am still not sure as to what is the source of this discrepancy. After a few tests I think this can be caused by improper parameterization of the bonds but I am not sure how to go about correcting any discrepancies. On Fri, Sep 13, 2013 at 5:53 PM, Dr. Vitaly Chaban vvcha

Re: [gmx-users] Distance calculation

2013-09-14 Thread Dr. Vitaly Chaban
g_mindist also has something useful in this direction, I guess. Dr. Vitaly V. Chaban On Sat, Sep 14, 2013 at 12:10 AM, Rama ramkishn...@gmail.com wrote: Hi , I there any tool to calculate distance between particular atom from one group(protein) to particular atom from another group(DMPC

Fwd: [gmx-users] SD integrator

2013-09-13 Thread Dr. Vitaly Chaban
There must be some problem with degrees of freedom in your system... Dr. Vitaly V. Chaban -- Forwarded message -- From: HANNIBAL LECTER hanniballecte...@gmail.com Date: Fri, Sep 13, 2013 at 7:15 PM Subject: [gmx-users] SD integrator To: Discussion list for GROMACS users

Re: Fwd: [gmx-users] SD integrator

2013-09-13 Thread Dr. Vitaly Chaban
to some parameters for CNT. On Fri, Sep 13, 2013 at 1:50 PM, HANNIBAL LECTER hanniballecte...@gmail.com wrote: I am position restraining the CNT group. That affects the degrees of freedom. On Sep 13, 2013 1:43 PM, Dr. Vitaly Chaban vvcha...@gmail.com wrote: There must be some problem

Re: [gmx-users] GaussView 4.0 and ITP adjuster

2013-09-09 Thread Dr. Vitaly Chaban
Hmmm GaussView is a supplement to Gaussian to prepare input files and visualize some (but far not all) results. Of course, it has nothing to do with gromacs and its topologies. Or, do I misunderstand you? Dr. Vitaly V. Chaban On Sun, Sep 8, 2013 at 1:29 PM, MUSYOKA THOMMAS

Re: [gmx-users] GaussView 4.0 and ITP adjuster

2013-09-09 Thread Dr. Vitaly Chaban
. Thank you. http://www.hindawi.com/journals/chem/2013/803151/ On Mon, Sep 9, 2013 at 12:46 PM, Dr. Vitaly Chaban vvcha...@gmail.comwrote: Hmmm GaussView is a supplement to Gaussian to prepare input files and visualize some (but far not all) results. Of course, it has nothing to do

Re: [gmx-users] Re: periodic_molecule missing interactions

2013-08-30 Thread Dr. Vitaly Chaban
I think it is a dangerous practice to simulate with a cutoff of 0.5 nm. Irrespectively of what you study. Dr. Vitaly V. Chaban On Fri, Aug 30, 2013 at 11:32 AM, Valentina valentina.erast...@durham.ac.uk wrote: Thank you for your reply. My box is quite small indeed, so my cut-offs are 0.5

Re: [gmx-users] psf to tpr

2013-08-16 Thread Dr. Vitaly Chaban
No, it is not. But you can at least convert coordinates via VMD. If you want to use gromacs trajectory analysis tools, it is easier to convert NAMD trajectory to gromacs trajectory. Otherwise, I have no idea why one may need to jump between codes. Dr. Vitaly V. Chaban On Fri, Aug 16, 2013 at

Re: [gmx-users] Lateral Diffusion of Lipids

2013-08-12 Thread Dr. Vitaly Chaban
Via an index file, I would guess... Or what do you mean exactly? Dr. Vitaly V. Chaban On Mon, Aug 12, 2013 at 5:26 AM, Kieu Thu Nguyen kieuthu2...@gmail.comwrote: Dear users, I want to use g_msd to measure diffusion coefficients of lipid bilayer. But i do not know how to choose the

Re: [gmx-users] Force Field for peptides and proteins

2013-08-12 Thread Dr. Vitaly Chaban
I like CHARMM. Dr. Vitaly V. Chaban On Mon, Aug 12, 2013 at 2:19 PM, Maria Astón Serrano m.aston.serr...@gmail.com wrote: Dear Gromacs users, We would like to know which is the Force Field which is customarily preferred for simulations of peptides and proteins. Thank you very much.

Re: [gmx-users] GROMACS 4.6.3 Static Linking

2013-07-20 Thread Dr. Vitaly Chaban
Soneone said here that static versions are impossible for Cray... Dr. Vitaly V. Chaban On Fri, Jul 19, 2013 at 12:55 PM, Andrew R Turner a.tur...@epcc.ed.ac.ukwrote: Hi I am having problems creating static versions of the GROMACS binaries for a Cray XE6 (www.hector.ac.uk). The build

Re: [gmx-users] Chlorate ion force field

2013-07-16 Thread Dr. Vitaly Chaban
I am afraid you will need to derive it from scratch. There should be some studies about perchlorate salts in literature. Make a search. Dr. Vitaly V. Chaban On Tue, Jul 16, 2013 at 6:08 AM, Sushma Yadav sushc...@gmail.com wrote: Dear users, How do I get the force-field for ClO4- ion in

Re: [gmx-users] snapshot

2013-07-15 Thread Dr. Vitaly Chaban
look for either -dt or -skip. Dr. Vitaly V. Chaban On Mon, Jul 15, 2013 at 2:03 AM, Rama ramkishn...@gmail.com wrote: Hi, How to get a snapshots in equal intervals of time (250ps) from production MD trajectory. I'm using -sep , -t0, -timestep but output came only one .gro file. --

Re: [gmx-users] How to calculate enthalpy

2013-07-15 Thread Dr. Vitaly Chaban
Sure, you can. Dr. Vitaly V. Chaban On Mon, Jul 15, 2013 at 8:38 AM, pooja_gu...@nccs.res.in wrote: Hi I want calculate the enthalpy of water molecule corresponding to protein folded and unfolded state. How much a single water molecule (enthalpy and free energy) contribute in folding ?

Re: [gmx-users] How to calculate enthalpy

2013-07-15 Thread Dr. Vitaly Chaban
H = U +pV, all these terms are available through g_energy. Your resulting values will be per mole, so I would perform no additional normalization. Personally, I would simulate all cases (folded, unfolded, etc) with the same number of waters -- to avoid any possible artifacts. Dr. Vitaly V.

Re: [gmx-users] Mass in GMX topology

2013-07-13 Thread Dr. Vitaly Chaban
On Thu, Jul 11, 2013 at 1:17 PM, Steven Neumann s.neuman...@gmail.comwrote: Thank you. Another question: Does RDF depends on the mass of the atom? On the one hand it gives different value of the force in equation of motion but on the other hand velocities are rescaled with a thermostat. It

Re: [gmx-users] Xe atom

2013-07-11 Thread Dr. Vitaly Chaban
...@gmail.comwrote: ya.. but there is experimental data to confirm the presence. can you help me to solve this problem On 9 July 2013 11:54, Dr. Vitaly Chaban vvcha...@gmail.com wrote: Is this, http://en.wikipedia.org/wiki/Xenon, your Xe ? If so, it will obviously not sit in the binding site

Re: [gmx-users] Cyclohexane as a solvent

2013-07-11 Thread Dr. Vitaly Chaban
if you prepare a separate ITP for each solvent, you will save some nerves in the long term Dr. Vitaly V. Chaban On Thu, Jul 11, 2013 at 7:14 PM, Justin Lemkul jalem...@vt.edu wrote: On 7/11/13 8:59 AM, Shima Arasteh wrote: Dear all, I see cyclohexane parameters in top par CGenFF

Re: [gmx-users] Xe atom

2013-07-09 Thread Dr. Vitaly Chaban
to simply add the xe parameters to .gro file and topol file? or may i need to make changes in forcefield? pls help Thanking you Divya On 8 July 2013 19:16, Dr. Vitaly Chaban vvcha...@gmail.com wrote: I am a too curious person not to ask WHY Xe is of interest in connection

Re: [gmx-users] Xe atom

2013-07-08 Thread Dr. Vitaly Chaban
I am a too curious person not to ask WHY Xe is of interest in connection with the protein..? Dr. Vitaly V. Chaban On Mon, Jul 8, 2013 at 6:45 PM, Justin Lemkul jalem...@vt.edu wrote: On 7/8/13 9:21 AM, divyasunil wrote: Hello, Please help me to add Xe atom to GROMOS96 53a6 force field.

Re: [gmx-users] new forcefield not appear in slave node pdb2gmx list

2013-07-06 Thread Dr. Vitaly Chaban
I think this question is for the developers of your operating system ... Dr. Vitaly V. Chaban On Sat, Jul 6, 2013 at 6:10 PM, Hari Pandey hariche...@yahoo.com wrote: Hi all gromacs users, I have new forcefield and I have this folder in my working directory as well as in

Re: [gmx-users] Re: g_velacc

2013-07-05 Thread Dr. Vitaly Chaban
Use this command line: -- g_velacc -nonormalize -acflen 2001 -- g_integrate -f vac.xvg -integrate -- Multiply the resulting value by 333.333, the result will be self-diffusion coefficient expressed as result * 10^(-9) m^2/s. The velocities should be written down at least every 10fs during MD.

Re: [gmx-users] Re: g_velacc

2013-07-05 Thread Dr. Vitaly Chaban
g_integrate should be g_analyze below. Sorry. On Fri, Jul 5, 2013 at 12:20 PM, Dr. Vitaly Chaban vvcha...@gmail.comwrote: Use this command line: -- g_velacc -nonormalize -acflen 2001 -- g_integrate -f vac.xvg -integrate -- Multiply the resulting value by 333.333, the result will be self

Re: [gmx-users] shell MD

2013-07-05 Thread Dr. Vitaly Chaban
In which case can the determinant not be computed? Dr. Vitaly V. Chaban On Thu, Jul 4, 2013 at 10:53 AM, Sergey gandalfg...@yandex.ru wrote: Dear users, I'm trying to run MD with SWM4-DP model (data from http://virtualchemistry.org), but I always have error: Can not invert matrix,

Re: [gmx-users] shell MD

2013-07-05 Thread Dr. Vitaly Chaban
was successful. 05.07.2013, 14:48, Dr. Vitaly Chaban vvcha...@gmail.com: In which case can the determinant not be computed? Dr. Vitaly V. Chaban On Thu, Jul 4, 2013 at 10:53 AM, Sergey gandalfg...@yandex.ru wrote: Dear users, I'm trying to run MD with SWM4-DP model (data from http

Re: [gmx-users] shell MD

2013-07-05 Thread Dr. Vitaly Chaban
, can :) I will have to run shell MD in NAMD, though it will be slower a bit. Seemingly, only Vitaly see my problem :). 05.07.2013, 16:31, Dr. Vitaly Chaban vvcha...@gmail.com: The was a bug report on this error a few years ago, http://redmine.gromacs.org/issues/332 Can your problem

Re: [gmx-users] Re: Re: Lennard-Jones potential for protons

2013-07-04 Thread Dr. Vitaly Chaban
why not to pick up a QM technique to study the interaction? Dr. Vitaly V. Chaban On Thu, Jul 4, 2013 at 3:58 AM, Jong Wha Lee jongwh...@postech.ac.krwrote: Thank you Mark and Vitaly. I understand that simulation of protons in the solution phase is unphysical. Though I haven't mentioned

Re: [gmx-users] Re: g_velacc

2013-07-04 Thread Dr. Vitaly Chaban
It would be nice to see plotted velocity autocorrelation function, VACF, which you integrate? The resulting diffusion constant looks crazy large, so there must be something rotten in the VACF. Dr. Vitaly V. Chaban On Thu, Jul 4, 2013 at 8:32 AM, Ishwor ishwor.poudya...@gmail.com wrote: I

Re: [gmx-users] Lennard-Jones potential for protons

2013-07-03 Thread Dr. Vitaly Chaban
I am also not aware of the force field parameters for hydrated/solvated proton, but maybe I am just wrong here. An attempt to describe proton with Newtonian dynamics will unlikely give you anything similar to reality. Lennard-Jones parameters play no role here, by the way, some force fields

Re: [gmx-users] Atomtype OWT3 not found during EM step

2013-07-03 Thread Dr. Vitaly Chaban
I would guess the new atom type should be in the ITP file. And of course, you are expected to define bonded and nonbonded terms for all applicable pairs, triples... of atoms. Good luck. Dr. Vitaly V. Chaban On Wed, Jul 3, 2013 at 6:41 PM, Juganta K. Roy juganta...@yahoo.com wrote: Dear all,

Re: [gmx-users] System expansion

2013-06-20 Thread Dr. Vitaly Chaban
Hi Oliver - Hmm. Did you try to start from (a little bit) different configurations on the problematic machine? Or re-install gromacs there, perhaps? Dr. Vitaly Chaban On Thu, Jun 20, 2013 at 3:44 PM, Oliver Schillinger o.rus...@fz-juelich.dewrote: Dear Gromacs users, I experience

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 mailmd2...@gmail.com wrote: Hello : I am going to use Gromacs with PLUMD plugin to perform Metadynamics. Since this methods

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 s.neuman...@gmail.comwrote: Dear Gmx Users, I am running CG simulation and I wish my beads to be constraint - one away from each other of 0.4

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

2013-06-11 Thread Dr. Vitaly Chaban
. The larger *spatially) system you simulate, the more likely it to appear. The simple advice is to reduce the time-step, but it is not to be understood as a universal treatment. Of course, you can reinitialize your charge groups, as this is better connected with the below error message. Dr. Vitaly

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

2013-06-11 Thread Dr. Vitaly Chaban
annealing, which you do not list here. Dr. Vitaly Chaban -- gmx-users mailing listgmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/Search before posting! * Please don't post (un)subscribe

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 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 versions up to 4.0.7. It is not always connected to blowing up in the sense

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 s.neuman...@gmail.comwrote: I was not sure about the fucntion type (1

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 nshafi...@wesleyan.edu wrote: Hi everybody, I am trying to simulate a lipid bilayer and wanted to use Parrinello Rahman

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 hoe

Re: [gmx-users] Can we connect two boxes together for the simulation?

2013-06-04 Thread Dr. Vitaly Chaban
editconf is a nice tool to create vacuum in your box. You can then insert one of your box into another box using cat box1.gro box2.gro, just remove the very last line in box1.gro. Dr. Vitaly Chaban On Tue, Jun 4, 2013 at 2:46 PM, Bao Kai paeanb...@gmail.com wrote: Hi, all, I want

Re: [gmx-users] Can we connect two boxes together for the simulation?

2013-06-04 Thread Dr. Vitaly Chaban
Nohow. Numbers in GRO files serve exclusively decorative function. Dr. Vitaly Chaban On Tue, Jun 4, 2013 at 4:12 PM, Bao Kai paeanb...@gmail.com wrote: Hi, I guess the renumbering of the atoms and molecules will be a problem, especially when the two boxes contain the same type

Re: [gmx-users] ngmx not installed in gmx4.6.1

2013-06-04 Thread Dr. Vitaly Chaban
I do not know about the newest versions, but in older ones ngmx was missed when you did not have the lesstif library installed. Dr. Vitaly Chaban On Tue, Jun 4, 2013 at 5:55 PM, Chandan Choudhury iitd...@gmail.com wrote: Dear gmx users, I had installed gromacs 4.6.1 using cmake. All

Re: [gmx-users] .GRO Formatting

2013-05-30 Thread Dr. Vitaly Chaban
In GRO file, the atom numbers do not really matter. Just use any number you like. It will work correctly. mdrun will renumber atoms from 9, as it likes, automatically. Dr. Vitaly Chaban On Thu, May 30, 2013 at 4:57 AM, Phil pmcho...@syr.edu wrote: I'm working on a .GRO file and have

Re: [gmx-users] Difference between the electrostatic treatments PME/Cut-offs and Reaction Field

2013-05-30 Thread Dr. Vitaly Chaban
Hmmm... And what does the observed difference look like, numerically? On Thu, May 30, 2013 at 10:14 AM, Mark Abraham mark.j.abra...@gmail.comwrote: No charges = no problem. You can trivially test this yourself with mdrun -rerun ;-) Manual 4.1.4 talks about what RF is doing. Mark On

Re: [gmx-users] Continue simulation from the specific time

2013-05-29 Thread Dr. Vitaly Chaban
If the frame was saved to the trajectory file, just extract it with trjconv -dump $timeframe -o conf.gro and continue your MD. No need for any additional energy minimizations, of course. Dr. Vitaly Chaban On Wed, May 29, 2013 at 12:45 PM, Андрей Гончар gontc...@gmail.com wrote: Hello

Re: [gmx-users] Continue simulation from the specific time

2013-05-29 Thread Dr. Vitaly Chaban
Aside from original question, you will probably want to initialize velocities (gen_vel) in order to evolve a different trajectory rather than repeating previous one. Dr. Vitaly Chaban On Wed, May 29, 2013 at 1:00 PM, Dr. Vitaly Chaban vvcha...@gmail.comwrote: If the frame was saved

[gmx-users] Re: choice of force field -reg

2013-05-29 Thread Dr. Vitaly Chaban
If you want to observe H-bond dynamics and do it with an atomistic precision than, of course, you need an all-atom representation. United atoms will still *effectively* account for H-bonding, if you are happy with reduced precision. Dr. Vitaly Chaban On Wed, May 29, 2013 at 8:01 AM, Revthi

Re: [gmx-users] How to choose bd_fric value in brownian dynamics

2013-05-29 Thread Dr. Vitaly Chaban
According to my understanding, setting friction coefficient is quite a personal thing. The higher is bd-fric, the smaller are velocities. Why not to set bd-fric = 0 in order to start with? See manual for details of how this trick works. Dr. Vitaly Chaban On Wed, May 29, 2013 at 11:48 AM

Re: [gmx-users] How to choose bd_fric value in brownian dynamics

2013-05-29 Thread Dr. Vitaly Chaban
. Why don't you want to use molecular dynamics? Dr. Vitaly Chaban On Wed, May 29, 2013 at 4:10 PM, Mohan maruthi sena maruthi.s...@gmail.comwrote: Hello Sir , Thanks for your quick reply. I have used bd_fric =0 and then my simulation is blowing up. I have used a time step of 0.002ps

Re: [gmx-users] Extending simualtions

2013-05-29 Thread Dr. Vitaly Chaban
Tnks I believe the idea is that you should have trajectory file, energy file, logfile, etc, so that gromacs could append them. If they have non-default name, you probably should specify them explicitly in the invocation line. Dr. Vitaly Chaban Fábio Filippi MatioliGraduando em

Re: [gmx-users] pulling simulations

2013-05-29 Thread Dr. Vitaly Chaban
The force should not probably exceed kT product too much... Dr. Vitaly Chaban On Wed, May 29, 2013 at 3:19 PM, Sathish Kumar sathishk...@gmail.comwrote: Dear Sir, In pulling simulations how to set pull_rate and pull_k .On which basis we can set these values

[gmx-users] Re: Extending simulations

2013-05-29 Thread Dr. Vitaly Chaban
I do not remember all the keys. Rename your files to their default names and you will have nothing to specify except mdrun -cpi On Wed, May 29, 2013 at 6:31 PM, Fábio Filippi Matioli fabiof...@hotmail.com wrote: Hello, i'm who asked about extending simulations. You sad for me pen teh

[gmx-users] Re: Extending simulations

2013-05-29 Thread Dr. Vitaly Chaban
perhaps mdrun -cpi -deffnm full will also do the job in your case On Wed, May 29, 2013 at 6:36 PM, Dr. Vitaly Chaban vvcha...@gmail.comwrote: I do not remember all the keys. Rename your files to their default names and you will have nothing to specify except mdrun -cpi On Wed, May

Re: [gmx-users] Gromacs for Non biological systems

2013-05-28 Thread Dr. Vitaly Chaban
Look for my papers. At least, two dozens of them are about non-biophysical stuff. Gromacs can. The question is whether you can provide an adequate Hamiltonian to describe your systems involving Al-surface. Dr. Vitaly Chaban On Mon, May 27, 2013 at 10:59 PM, Jeya vimalan jeyavimala

Re: [gmx-users] choice of forcefield

2013-05-28 Thread Dr. Vitaly Chaban
In my mind, MARTINI is a decent option to build your particular topology upon. Dr. Vitaly Chaban On Tue, May 28, 2013 at 8:22 AM, Revthi Sanker revthi.san...@yahoo.comwrote: Dear all, I am a beginner to performing simulations and my system consists of protein+ cholesteryl ester

[gmx-users] Re: choice of force field -reg

2013-05-28 Thread Dr. Vitaly Chaban
without knowing full details of your simulated system and the goals you pose, I cannot advise anything more definite than I did before. if I were you and my system were yours, I would start with MARTINI FF. I wish you a success in your endeavor. Dr. Vitaly Chaban On Tue, May 28, 2013 at 6

Re: [gmx-users] how to get the epsilon and sigma values of CO

2013-05-27 Thread Dr. Vitaly Chaban
if there are many values in the literature, what do you want? On Mon, May 27, 2013 at 4:29 PM, Ishwor Poudyal ishwor_p...@hotmail.comwrote: Dear all.I want to study simulation of carbonmonoxide in water...I get different values of force constant partial charge while searching for those

Re: [gmx-users] Why the shape of the molecules changed?

2013-05-25 Thread Dr. Vitaly Chaban
Of course, you can simulate what you like, but I would personally use an all-atom representation for long hydrocarbons. I think explicit hydrogens matter for conformations. V.V. Chaban On Thu, May 23, 2013 at 5:16 PM, Bao Kai paeanb...@gmail.com wrote: Hi, all, I finally wrote a decane

[gmx-users] DD fails

2013-05-19 Thread Dr. Vitaly Chaban
that it happens? Thank you. Dr. Vitaly Chaban -- gmx-users mailing listgmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/Search before posting! * Please don't post (un)subscribe requests

[gmx-users] Re: DD fails

2013-05-19 Thread Dr. Vitaly Chaban
UPD: the version of gromacs exhibiting this marvellous behavior is 4.5.5. On Mon, May 20, 2013 at 8:11 AM, Dr. Vitaly Chaban vvcha...@gmail.comwrote: any ideas what the below error message can indicate? Step 350755: The charge group starting at atom 44257 moved than the distance allowed

Re: [gmx-users] Charmm27 potential energies.

2013-05-09 Thread Dr. Vitaly Chaban
electrostatic charges for each site. Dr. Vitaly Chaban On Thu, May 9, 2013 at 11:33 PM, Eric Stokes es...@uw.edu wrote: Hello, I am attempting to generate force-field parameters for a fatty acid molecule that contains a carboxilic acid head group. I decided to use the parameters for stearic

Re: [gmx-users] Usage of g_spatial

2013-05-07 Thread Dr. Vitaly Chaban
I think you can process the trajectories without generating TPR. Dr. Vitaly Chaban On Tue, May 7, 2013 at 12:12 PM, Venkat Reddy venkat...@gmail.com wrote: Dear gromacs users, I am analyzing trajectories of an ionic liquid system generated using AMBER MD package. The force field parameters

Re: [gmx-users] simulation single molecule in water

2013-05-07 Thread Dr. Vitaly Chaban
Your problem has nothing to do with barostat. There is such thing as DispCorr. I am unsure whether if should be turned on or off in case of your model. It does influence density to certain extent. Dr. Vitaly Chaban -Original Message- From: gmx-users-boun...@gromacs.org

Re: [gmx-users] where can be obtain circled lipids bilayer?

2013-05-02 Thread Dr. Vitaly Chaban
parameter of the the lipid is large enough. 2) When concentration of lipids in the box is reasonably low. Dr. Vitaly Chaban thank you very much Albert -- gmx-users mailing listgmx-users@gromacs.org http://lists.gromacs.org/**mailman/listinfo/gmx-usershttp://lists.gromacs.org/mailman

Re: [gmx-users] vacum simulation

2013-05-02 Thread Dr. Vitaly Chaban
LINCS doesn't like your system... or your system doesn't like LINCS... You can decrease the time-step as the simplest action. Dr. Vitaly Chaban On Thu, May 2, 2013 at 2:40 PM, Souilem Safa safasouil...@gmail.com wrote: Dear Gromacs users , I did the simulation of a single molecule

Re: [gmx-users] g_msd for many molecules

2013-05-01 Thread Dr. Vitaly Chaban
The resulting MSD will correspond to the average from individual atoms. Calculating MSD of an individual atom and ascribing it to a [small] molecule, which this atom belongs to, is reasonable. Assuming that averaged MSD from atoms correspond to the cluster they form is not. Dr. Vitaly Chaban

Re: [gmx-users] Martini with PME, temp two low

2013-04-25 Thread Dr. Vitaly Chaban
Hmmm Aren't the keywords here charged system + PME? Dr. Vitaly Chaban On Thu, Apr 25, 2013 at 1:34 PM, XAvier Periole x.peri...@rug.nl wrote: Did you visualise the system? T in function of time? Epot in function of time? As a side note (not relevant for PME) the mix of nstlist = 10

Re: [gmx-users] Problem with gromacs in Cluster

2013-04-25 Thread Dr. Vitaly Chaban
The salvation is to use: mdrun -cpi state.cpt Dr. Vitaly Chaban On Thu, Apr 25, 2013 at 2:37 PM, Justin Lemkul jalem...@vt.edu wrote: Can any body tell me how do it split script i such that i will get all 20ns simulation You specified a given time limit for the job, and the run

Re: [gmx-users] Martini with PME, temp two low

2013-04-25 Thread Dr. Vitaly Chaban
Aren't the keywords here charged system + PME? Dr. Vitaly Chaban On Thu, Apr 25, 2013 at 1:34 PM, XAvier Periole x.peri...@rug.nl wrote: Did you visualise the system? T in function of time? Epot in function of time? As a side note (not relevant for PME) the mix of nstlist = 10

Re: [gmx-users] using CHARMM force field for organic molecule

2013-04-22 Thread Dr. Vitaly Chaban
a simple way is x2top Dr. Vitaly Chaban On Mon, Apr 22, 2013 at 1:38 PM, aixintiankong aixintiank...@126.comwrote: Dear , I want to use charmm force field to simulate the protein and ligand system. The protein can selcet charmm27 in gromacs, but i don't konw how to get the charmm

[gmx-users] Re: Water spreading on graphene!

2013-04-21 Thread Dr. Vitaly Chaban
interactions, which you would not have had in real experiment. I also expect a specific behavior, if your droplet is very small. Maybe, I would simulate this system without PBC at all. Dr. Vitaly Chaban I have a graphene like surface (carbons on a hexagonal lattice with zero partial charges

[gmx-users] Re: Viscosity calculation using cos_acceleration

2013-04-16 Thread Dr. Vitaly Chaban
ability a workability of the utility. It has been tried many times and works really perfectly. Dr. Vitaly Chaban -- gmx-users mailing listgmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/Search

Re: [gmx-users] Re: RDF output has no data

2013-04-09 Thread Dr. Vitaly Chaban
So there is a problem with your trajectory file. Try to understand what kind of problem it is. I can recollect that I experienced something like that why translating CPMD trajectory to GROMACS. Maybe, it does not write time for each frame at the right place -- just a guess. Dr. Vitaly Chaban

Re: [gmx-users] Re: How to set the sigma and epsilon for Cu2+ in OPLS-AA/L

2013-04-09 Thread Dr. Vitaly Chaban
On Tue, Apr 9, 2013 at 9:39 AM, fantasticqhl fantastic...@gmail.com wrote: Dear Dr. Vitaly Chaban, Thanks very much for your patient and detailed suggestions on this problem. Actually, I am doing what your suggested now. I optimized the copper-ligand complex using QM method, and then did

Re: [gmx-users] Re: How to set the sigma and epsilon for Cu2+ in OPLS-AA/L

2013-04-09 Thread Dr. Vitaly Chaban
On Tue, Apr 9, 2013 at 11:03 AM, fantasticqhl fantastic...@gmail.comwrote: Dear Dr. Vitaly Chaban, Thanks very much again. I am sorry for the unclear, charge transfer was also taken into account for the complex, I did not mentioned in the last e-mail. What do you mean by finite T effect

[gmx-users] Re: Lipid membrane partially broken and create huge voids

2013-04-09 Thread Dr. Vitaly Chaban
is no showing in VMD. Could any suggestions on this behavior. I think your particles are still there... Try to adjust VMD settings. Dr. Vitaly Chaban -- gmx-users mailing listgmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users * Please search the archive at http

[gmx-users] Re: Simulating a large system

2013-04-08 Thread Dr. Vitaly Chaban
Hi, is it possible to instruct gromacs to only perform the dynamics on half of the system or protein while ignoring the rest? thanks Would you explain to us why you need so exotic setup? Dr. Vitaly Chaban -- gmx-users mailing listgmx-users@gromacs.org http://lists.gromacs.org/mailman

[gmx-users] Re: can we use GPU from another machine for calculation?

2013-04-08 Thread Dr. Vitaly Chaban
... I am not an expert in this question, but intuitively the bandwidth between your two workstations will likely kill most of the anticipated performance gain. Dr. Vitaly Chaban -- gmx-users mailing listgmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users * Please search

[gmx-users] Re: Simulating a large system

2013-04-08 Thread Dr. Vitaly Chaban
If you do not care about the atoms, which are too far away from the region of interest, is it not reasonable just to cut that useless part? Also, you may want to look towards implicit solvent simulations. Dr. Vitaly Chaban On Mon, Apr 8, 2013 at 11:35 AM, Juan Antonio Raygoza Garay raygo

Re: [gmx-users] Re: How to set the sigma and epsilon for Cu2+ in OPLS-AA/L

2013-04-08 Thread Dr. Vitaly Chaban
? Dr. Vitaly Chaban On Mon, Apr 8, 2013 at 1:09 PM, fantasticqhl fantastic...@gmail.com wrote: Dear Dr. Vitaly Chaban, Thanks very much for your explanation. I guess that I get what you mean now! Thanks! All the best, Qinghua Liao On 04/07/2013 11:35 AM, Dr. Vitaly Chaban wrote

[gmx-users] Re: RDF output has no data

2013-04-08 Thread Dr. Vitaly Chaban
I believe the problem is in the way which you used to convert AMBER trajectory to the GROMACS trajectory I would suggest to try gmxdump and see what your trajectory looks like. Oe maybe even better - try to visualize it in VMD to see if the format is correct. Dr. Vitaly Chaban Sir I

Re: [gmx-users] Re: How to set the sigma and epsilon for Cu2+ in OPLS-AA/L

2013-04-08 Thread Dr. Vitaly Chaban
distances AFTER you turn on all the necessary potentials (Coulombic attraction in case of OPLS). Dr. Vitaly Chaban On Mon, Apr 8, 2013 at 3:14 PM, fantasticqhl fantastic...@gmail.com wrote: Dear Dr. Vitaly Chaban, Thanks very much for concern on my research! We are going to the use

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