Re: [gmx-users] trjcat after trjconv

2013-09-26 Thread Tsjerk Wassenaar
Yes. Cheers, Tsjerk On Fri, Sep 27, 2013 at 7:51 AM, Venkat Reddy wrote: > Thanks for the quick reply sir. > So, does it mean I can apply "trjcat" on the processed xtc files??? > > > On Thu, Sep 26, 2013 at 10:25 PM, Tsjerk Wassenaar >wrote: > > > Hi Venkat, > > > > These options are 'frame

Re: [gmx-users] trjcat after trjconv

2013-09-26 Thread Venkat Reddy
Thanks for the quick reply sir. So, does it mean I can apply "trjcat" on the processed xtc files??? On Thu, Sep 26, 2013 at 10:25 PM, Tsjerk Wassenaar wrote: > Hi Venkat, > > These options are 'frame intrinsic' or 'history independent', unlike -pbc > nojump. > > Cheers, > > Tsjerk > > On Sep 26,

Re: [gmx-users] Writing periodic image coordinates.

2013-09-26 Thread Kavyashree M
Thank you Sir! Regards Kavya On Fri, Sep 27, 2013 at 12:52 AM, Tsjerk Wassenaar wrote: > Hi Kavya, > > genconf -nbox 3 3 3 > > Cheers, > > Tsjerk > > > On Thu, Sep 26, 2013 at 6:24 PM, Kavyashree M wrote: > > > Dear users, > > > > For some analysis I require the 27 periodic images > > of the s

[gmx-users] OPLS/AA + TIP5P, anybody?

2013-09-26 Thread Christopher Neale
Dear Gigo: I've never used tip5p, but perhaps you could add some LJ terms to the opls_120 definition, do your minimization, then remove the fake LJ term on opls_120 and run your MD? If that doesn't work, then you might be able to minimize your system using FLEXIBLE tip3p water and then use a sc

Re: [gmx-users] "Illegal instruction" error from alchemical-gromacs.py

2013-09-26 Thread Michael Shirts
Hi, Chris- The best place to file this issue is the SimTK pymbar page, rather than alchemistry.org, since it's a pymbar problem. We have collaborators that may have updated the pymbar.py recently. I'll try to get this stabilized in the very near future. Testing quickly, my best guess is that it'

Re: [gmx-users] Membrane simulation with OPLS ff.

2013-09-26 Thread Justin Lemkul
On 9/26/13 10:47 PM, Christopher Neale wrote: Dear Karthi: As far as I am aware, there is no OPLSAA lipid force field. I have used Berger lipids with OPLSAA protein ( http://www.pomeslab.com/files/lipidCombinationRules.pdf ) but that is mixing a UA lipid with an AA protein so be aware of pos

[gmx-users] Membrane simulation with OPLS ff.

2013-09-26 Thread Christopher Neale
Dear Karthi: As far as I am aware, there is no OPLSAA lipid force field. I have used Berger lipids with OPLSAA protein ( http://www.pomeslab.com/files/lipidCombinationRules.pdf ) but that is mixing a UA lipid with an AA protein so be aware of possible problems arising out of that. Charmm has pr

[gmx-users] "Illegal instruction" error from alchemical-gromacs.py

2013-09-26 Thread Christopher Neale
Dear Users: I'm having difficulty running MBAR after some free energy calculations (MBAR via alchemical-gromacs.py obtained from alchemistry.org). The input options to alchemical-gromacs.py have obviously changed since the site at http://www.alchemistry.org/wiki/GROMACS_4.6_example:_Direct_etha

Re: [gmx-users] segfault when running the alchemistry.org ethanol solvation free energy tutorial

2013-09-26 Thread Michael Shirts
Sounds like we've resolved all the confusion. Thanks for prompt help in making this clearer and better. On Thu, Sep 26, 2013 at 7:01 PM, Christopher Neale wrote: > Agreed, the following parameters do not segfault in single or double > precision: > sc-alpha = 0.5 > sc-power

[gmx-users] segfault when running the alchemistry.org ethanol solvation free energy tutorial

2013-09-26 Thread Christopher Neale
Agreed, the following parameters do not segfault in single or double precision: sc-alpha = 0.5 sc-power = 1 sc-r-power = 6 Same goes for http://bugzilla.gromacs.org/issues/1306 The following parameters give a segfault in single precision but are ok in

Re: [gmx-users] segfault when running the alchemistry.org ethanol solvation free energy tutorial

2013-09-26 Thread Michael Shirts
And with this change, single is running fine as well. This was a known issue, but was only documented in the expanded.mdp files, which was an oversight. After this, I switched so the default is less likely to cause problems. Because of some theory improvements developed in the group in free ener

Re: [gmx-users] segfault when running the alchemistry.org ethanol solvation free energy tutorial

2013-09-26 Thread Michael Shirts
I thought I had just managed to solve the issue :) If you look at the soft core parameters, there are two types listed -- one with sc-r-power = 48, and one with sc-r-power = 6. The sc-r-power are more stable with single precision calculations. I have changed the files on the website to make the

[gmx-users] segfault when running the alchemistry.org ethanol solvation free energy tutorial

2013-09-26 Thread Christopher Neale
No, this is not the expanded ensemble version. It's the initial "Running the calculation with Gromacs" section straight out of http://www.alchemistry.org/wiki/GROMACS_4.6_example:_Direct_ethanol_solvation_free_energy I get the segfault with a single run (at any of the 9 individual lambda values)

[gmx-users] segfault when running the alchemistry.org ethanol solvation free energy tutorial

2013-09-26 Thread Christopher Neale
My mistake I still get a segfault even when using double precision. (EM doesn't help, nor does switching to Berendsen pressure coupling). Note that I can stop the segfault when running at init-lambda-state = 0 if I set: couple-lambda0 = none couple-lambda1 = none inste

Re: [gmx-users] segfault when running the alchemistry.org ethanol solvation free energy tutorial

2013-09-26 Thread Michael Shirts
Just to be clear, is this the expanded ensemble version of the calculation? On Thu, Sep 26, 2013 at 5:25 PM, Mark Abraham wrote: > I found the -multi version of that tutorial a bit temperamental... > Michael Shirts suggested that double precision is more reliable for > expanded ensemble. Hopefull

[gmx-users] segfault when running the alchemistry.org ethanol solvation free energy tutorial

2013-09-26 Thread Christopher Neale
Thank you Mark. I actually found that it crashed wihout the -multi part (no hamiltonian exchange). The command that I used was: mdrun -nt 1 -deffnm ethanol.1 -dhdl ethanol.1.dhdl.xvg If I use the double precision version, there is no segfault. That's a working solution, but it is worrysome.

Re: [gmx-users] segfault when running the alchemistry.org ethanol solvation free energy tutorial

2013-09-26 Thread Mark Abraham
I found the -multi version of that tutorial a bit temperamental... Michael Shirts suggested that double precision is more reliable for expanded ensemble. Hopefully he can chime in in a day or two. Mark On Thu, Sep 26, 2013 at 9:00 PM, Christopher Neale wrote: > Dear Users: > > Has anyone success

[gmx-users] Membrane simulation with OPLS ff.

2013-09-26 Thread Karthigeyan.Nagarajan
Dear GMX users: Is OPLSAA forcefield data already available for POPC membranes. I am interested in simulation of proteins in POPC membrane. Thank you. Best Regards Karthi. -- gmx-users mailing listgmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users * Please search the ar

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

2013-09-26 Thread Justin Lemkul
On 9/26/13 10:19 AM, Dr. Vitaly Chaban wrote: 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

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

2013-09-26 Thread Justin Lemkul
On 9/26/13 12:05 PM, Dr. Vitaly Chaban wrote: Steven - I would use a simple harmonic bond. Note that either in the case of the distance restraint or harmonic interaction approach, both the CNT and the molecule to which it is tethered need to be in the same [moleculetype], so run pdb2gmx (

Re: [gmx-users] per mol of what?

2013-09-26 Thread Tsjerk Wassenaar
Hi Ángel, kJ per mol of system contained in the unit cell? > > Exactly. As if whatever is in there is one 'molecule' (-nmol 1). Adios! Tsjerk -- Tsjerk A. Wassenaar, Ph.D. -- gmx-users mailing listgmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users * Please searc

Re: [gmx-users] Writing periodic image coordinates.

2013-09-26 Thread Tsjerk Wassenaar
Hi Kavya, genconf -nbox 3 3 3 Cheers, Tsjerk On Thu, Sep 26, 2013 at 6:24 PM, Kavyashree M wrote: > Dear users, > > For some analysis I require the 27 periodic images > of the system I ran the simulation for. Kindly let me > know how can it be written to a pdb file. > > Thanking you > Regard

[gmx-users] segfault when running the alchemistry.org ethanol solvation free energy tutorial

2013-09-26 Thread Christopher Neale
Dear Users: Has anyone successfully run the free energy tutorial at http://www.alchemistry.org/wiki/GROMACS_4.6_example:_Direct_ethanol_solvation_free_energy ? I just tried it and I get a segmentation fault immediately (see output at the end of this post). I get a segfault with both 4.6.3 and

Re: [gmx-users] trjcat after trjconv

2013-09-26 Thread Tsjerk Wassenaar
Hi Venkat, These options are 'frame intrinsic' or 'history independent', unlike -pbc nojump. Cheers, Tsjerk On Sep 26, 2013 6:46 PM, "Venkat Reddy" wrote: Dear Tsjerk sir, I used trjconv -pbc mol -ur compact options. On Thu, Sep 26, 2013 at 9:17 PM, Tsjerk Wassenaar wrote: > Hi Venkat, > >

Re: [gmx-users] trjcat after trjconv

2013-09-26 Thread Venkat Reddy
Dear Tsjerk sir, I used trjconv -pbc mol -ur compact options. On Thu, Sep 26, 2013 at 9:17 PM, Tsjerk Wassenaar wrote: > Hi Venkat, > > It depends on what you mean with "removing pbc". > > Cheers, > > Tsjerk > > On Sep 26, 2013 5:21 PM, "Venkat Reddy" wrote: > > Dear Sir, > Thanks for the qui

[gmx-users] Writing periodic image coordinates.

2013-09-26 Thread Kavyashree M
Dear users, For some analysis I require the 27 periodic images of the system I ran the simulation for. Kindly let me know how can it be written to a pdb file. Thanking you Regards Kavya -- gmx-users mailing listgmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users * Pleas

[gmx-users] per mol of what?

2013-09-26 Thread Ángel Piñeiro
Hi when calculating an energy contribution using g_energy, the units specified in the plots, as well as in the output tables, are kJ/mol. This happens even when the -nmol flag is missing (so nmol=1). On the other hand, the energy units in gromacs are kJ/mol. So I guess that when a term (a dihedral

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

2013-09-26 Thread Dr. Vitaly Chaban
Steven - I would use a simple harmonic bond. Dr. Vitaly V. Chaban On Thu, Sep 26, 2013 at 5:12 PM, Steven Neumann wrote: > Thank you for this. And also I wish to attach a chain to my nanotube so they > will be both able to move together. Is that a matter of distance restraints > between nanot

Re: [gmx-users] trjcat after trjconv

2013-09-26 Thread Tsjerk Wassenaar
Hi Venkat, It depends on what you mean with "removing pbc". Cheers, Tsjerk On Sep 26, 2013 5:21 PM, "Venkat Reddy" wrote: Dear Sir, Thanks for the quick reply. I accidentally lost one of my raw .xtc files. But I have the noPBC xtc file. So, when ever I extend my simulation, first I am removin

Re: [gmx-users] trjcat after trjconv

2013-09-26 Thread Venkat Reddy
Dear Sir, Thanks for the quick reply. I accidentally lost one of my raw .xtc files. But I have the noPBC xtc file. So, when ever I extend my simulation, first I am removing PBC then concatenating it with existing noPBC xtc file. Is it fine?? On Thu, Sep 26, 2013 at 7:13 PM, Dr. Vitaly Chaban wrot

Re: [gmx-users] Preprocessor statements

2013-09-26 Thread Mark Abraham
No, there's no way to do that. But you can monitor the output trajectory file yourself, live. Mark On Thu, Sep 26, 2013 at 4:49 PM, Dr. Vitaly Chaban wrote: > Unlikely possible... But yeah, the feature might be handy. > > > Dr. Vitaly V. Chaban > > > On Thu, Sep 26, 2013 at 4:20 PM, grita wrote

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

2013-09-26 Thread Steven Neumann
Thank you for this. And also I wish to attach a chain to my nanotube so they will be both able to move together. Is that a matter of distance 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, a

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 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 molecules toge

[gmx-users] Preprocessor statements

2013-09-26 Thread grita
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 molecules together and I'd like to stop the simulation if the center of mass distance of the molecules is less than xx nm. Best, grita -- View this messa

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 c

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

2013-09-26 Thread Justin Lemkul
On 9/26/13 8:39 AM, Steven Neumann wrote: Dear Gmx Users, I have my carbon nanotube and I wish to make it infinite in lenght. Which mdp options whall be used? pbc = xy and z is the infinite dimension? another issue: Would you apply bonds between carbon atoms within the nanotube or constraints

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 wrote: > Dear all, > I have a basic doubt. Is there any difference between the two processes > where > 1) I concatenate the trajectories and do

[gmx-users] trjcat after trjconv

2013-09-26 Thread Venkat Reddy
Dear all, I have a basic doubt. Is there any difference between the two processes where 1) I concatenate the trajectories and do trjconv to remove PBC, which is a default process 2) Do trjconv on all the xtc files separately and then concatenate them. Thank you for your time -- With Best Wishes

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

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

2013-09-26 Thread Steven Neumann
Dear Gmx Users, I have my carbon nanotube and I wish to make it infinite in lenght. Which mdp options whall be used? pbc = xy and z is the infinite dimension? another issue: Would you apply bonds between carbon atoms within the nanotube or constraints using LINCS? Which of them is less computation