Re: [gmx-users] dt in mdp
On 4/10/20 4:17 PM, Alex wrote: On Fri, Apr 10, 2020 at 9:19 AM Justin Lemkul wrote: On 4/10/20 9:16 AM, Alex wrote: Thank you for the response. On Fri, Apr 10, 2020 at 9:02 AM Justin Lemkul wrote: On 4/10/20 8:13 AM, Alex wrote: Dear Justin, Any comment please? Sorry, haven't had power/network for a while due to some bad storms here. GROMOS force fields are parametrized assuming all bonds are fixed, so your constraints should be "all-bonds" not "h-bonds." Interesting, hopefully that is the problem. By constraining all the bonds "constraints = all-bonds", the simulation crashes in the first step immediately irrespective to the starting point of simulation, even if I continue the old working simulation. Now we're getting somewhere. That suggests that at least one bond has deviated substantially from its equilibrium length, such that the constraint algorithm fails immediately. This also likely underlies the original failure - forces are building up on some atoms such that mdrun crashes. You have either a bad geometry, inadequate topology, or both. Inspect the molecule(s) that mdrun complains about to see if the molecules are distorted by computing bond lengths and comparing against the force field's parameters. It may be beneficial to re-minimize and equilibrate with the proper constraint scheme after validating that the topology is of sufficient quality. -Justin -- == Justin A. Lemkul, Ph.D. Assistant Professor Office: 301 Fralin Hall Lab: 303 Engel Hall Virginia Tech Department of Biochemistry 340 West Campus Dr. Blacksburg, VA 24061 jalem...@vt.edu | (540) 231-3129 http://www.thelemkullab.com == -- Gromacs Users mailing list * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists * For (un)subscribe requests visit https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a mail to gmx-users-requ...@gromacs.org.
Re: [gmx-users] dt in mdp
On Fri, Apr 10, 2020 at 9:19 AM Justin Lemkul wrote: > > > On 4/10/20 9:16 AM, Alex wrote: > > Thank you for the response. > > > > > > On Fri, Apr 10, 2020 at 9:02 AM Justin Lemkul wrote: > > > >> > >> On 4/10/20 8:13 AM, Alex wrote: > >>> Dear Justin, > >>> Any comment please? > >> Sorry, haven't had power/network for a while due to some bad storms > here. > >> > >> GROMOS force fields are parametrized assuming all bonds are fixed, so > >> your constraints should be "all-bonds" not "h-bonds." > >> > > Interesting, hopefully that is the problem. > By constraining all the bonds "constraints = all-bonds", the simulation crashes in the first step immediately irrespective to the starting point of simulation, even if I continue the old working simulation. Regards, Alex > > > > > >> I would also suggest you thoroughly validate the quality of the epoxy > >> molecule topology against QM data and bulk-phase properties, if > possible. > >> > > As the ATB folks claim, the parameterization has been performed against a > > very high level DFT calculation, especially for the molecules with less > > than 50 atoms. > > I already have tested the density and it is in agreement with the > > experimental value. > > > > Regarding the "comm-grps = " , would you also please kindly let me know > > which one you would recommend for this system + plus a small single > > molecule called MOL_A which defuses from water inside the epoxy, > specially > > for the PMF calculation of the Mol_A? > > comm-grps = Other SOL ;; (Other = thin_film and Mol_A) > > or > > comm-grps = system > > I saw the conversation with David about this. I have nothing to add that > he hasn't already said. > > -Justin > > -- > == > > Justin A. Lemkul, Ph.D. > Assistant Professor > Office: 301 Fralin Hall > Lab: 303 Engel Hall > > Virginia Tech Department of Biochemistry > 340 West Campus Dr. > Blacksburg, VA 24061 > > jalem...@vt.edu | (540) 231-3129 > http://www.thelemkullab.com > > == > > -- > Gromacs Users mailing list > > * Please search the archive at > http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before > posting! > > * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists > > * For (un)subscribe requests visit > https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or > send a mail to gmx-users-requ...@gromacs.org. > -- Gromacs Users mailing list * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists * For (un)subscribe requests visit https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a mail to gmx-users-requ...@gromacs.org.
Re: [gmx-users] dt in mdp
On 4/10/20 9:16 AM, Alex wrote: Thank you for the response. On Fri, Apr 10, 2020 at 9:02 AM Justin Lemkul wrote: On 4/10/20 8:13 AM, Alex wrote: Dear Justin, Any comment please? Sorry, haven't had power/network for a while due to some bad storms here. GROMOS force fields are parametrized assuming all bonds are fixed, so your constraints should be "all-bonds" not "h-bonds." Interesting, hopefully that is the problem. I would also suggest you thoroughly validate the quality of the epoxy molecule topology against QM data and bulk-phase properties, if possible. As the ATB folks claim, the parameterization has been performed against a very high level DFT calculation, especially for the molecules with less than 50 atoms. I already have tested the density and it is in agreement with the experimental value. Regarding the "comm-grps = " , would you also please kindly let me know which one you would recommend for this system + plus a small single molecule called MOL_A which defuses from water inside the epoxy, specially for the PMF calculation of the Mol_A? comm-grps = Other SOL ;; (Other = thin_film and Mol_A) or comm-grps = system I saw the conversation with David about this. I have nothing to add that he hasn't already said. -Justin -- == Justin A. Lemkul, Ph.D. Assistant Professor Office: 301 Fralin Hall Lab: 303 Engel Hall Virginia Tech Department of Biochemistry 340 West Campus Dr. Blacksburg, VA 24061 jalem...@vt.edu | (540) 231-3129 http://www.thelemkullab.com == -- Gromacs Users mailing list * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists * For (un)subscribe requests visit https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a mail to gmx-users-requ...@gromacs.org.
Re: [gmx-users] dt in mdp
Thank you for the response. On Fri, Apr 10, 2020 at 9:02 AM Justin Lemkul wrote: > > > On 4/10/20 8:13 AM, Alex wrote: > > Dear Justin, > > Any comment please? > > Sorry, haven't had power/network for a while due to some bad storms here. > > GROMOS force fields are parametrized assuming all bonds are fixed, so > your constraints should be "all-bonds" not "h-bonds." > Interesting, hopefully that is the problem. > > I would also suggest you thoroughly validate the quality of the epoxy > molecule topology against QM data and bulk-phase properties, if possible. > As the ATB folks claim, the parameterization has been performed against a very high level DFT calculation, especially for the molecules with less than 50 atoms. I already have tested the density and it is in agreement with the experimental value. Regarding the "comm-grps = " , would you also please kindly let me know which one you would recommend for this system + plus a small single molecule called MOL_A which defuses from water inside the epoxy, specially for the PMF calculation of the Mol_A? comm-grps = Other SOL ;; (Other = thin_film and Mol_A) or comm-grps = system Thank you Alex > > -Justin > > > Regards, > > Alex > > > > On Tue, Apr 7, 2020 at 5:38 PM Alex wrote: > > > >> Thanks Justin for the response. > >> Please find below the mdp file. > >> The system is a thin film made out of a epoxy molecule, picture in be > >> below link, with water on top and bottom of the film. I even sometimes > have > >> the same issue when I simulate the bulk of this system, I mean a cubic > box > >> filled by this molecule and no water. > >> I got the force fields from the latest version of ATB repository by > which > >> I have previously done some other simulation for the same molecule. > >> > >> https://drive.google.com/open?id=1tJLxh9jQ2v5DDTrVR8IuQz40B3NN0zlb > >> > >> %mdp--- > >> title= Thin-Film > >> integrator = md > >> dt = 0.002 ; 2 fs ;0.001 1 fs > >> nsteps = 2500 ; 50 ns ;5000 ; 50 ns > >> xtc-precision= 500 ; 1000 > >> ;nstlist = 40 > >> %- > >> ;;in .trr file > >> nstxout = 3000 ; 6000 > >> nstvout = 0 > >> nstfout = 0 > >> ;;in energy file.log > >> nstlog = 2000 ; 4000 > >> nstcalcenergy= 2000 ;4000 > >> nstenergy= 2000 ;4000 > >> ;;in xtc file > >> nstxout-compressed = 0 > >> ;compressed-x-grps= non-Water > >> %- > >> continuation = yes > >> gen-vel = no > >> constraint-algorithm = lincs > >> constraints = h-bonds > >> cutoff-scheme= Verlet > >> coulombtype = PME > >> rcoulomb = 1.4 > >> > >> vdwtype = Cut-off > >> rvdw = 1.4 > >> DispCorr = EnerPres > >> > >> tcoupl= v-rescale > >> tc-grps = system > >> tau-t = 1.5 > >> nhchainlength = 10 > >> ref-t = 298.15 > >> pbc = xyz > >> > >> pcoupl = Parrinello-Rahman > >> Pcoupltype = isotropic > >> tau_p= 2.5 > >> compressibility = 4.5e-5 > >> ref_p= 1.0 > >> refcoord-scaling = com > >> energygrps = thin_film SOL > >> comm-mode= Linear > >> nstcomm = 100 > >> comm-grps= Thin_fiml SOL > >> %- > >> > >> Thank you > >> Alex > >> > >> On Tue, Apr 7, 2020 at 5:06 PM Justin Lemkul wrote: > >> > >>> > >>> On 4/7/20 5:00 PM, Alex wrote: > Dear all, > After minimization and equalizations using nvt (v-rescale) and npt > (both > berendsen and ;Parrinello-Rahman), a simulation of mine could run well > >>> for > 200 ns using dt =0.001 while it would crash after 3 ns If I used dt = > >>> 0.002 > with the particles communication fatal error. > > Fatal error: > 2 particles communicated to PME rank 12 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. > > So, if the system would not be well equlibrated, then I would expect > >>> that > with dt = 0.001 the simulation wouldn't run well for 200 ns. But I > >>> expect > that it also crashes for example around 6 ns as the with the dt = > 0.002 > >>> the > simulation last only 3 ns. > > Any comment that helps to understand the problem would be highly > appreciated. > >>> Please provide a description of what your system is and a full .mdp > >>> file. While most of the time these crashes come from poor >
Re: [gmx-users] dt in mdp
On 4/10/20 8:13 AM, Alex wrote: Dear Justin, Any comment please? Sorry, haven't had power/network for a while due to some bad storms here. GROMOS force fields are parametrized assuming all bonds are fixed, so your constraints should be "all-bonds" not "h-bonds." I would also suggest you thoroughly validate the quality of the epoxy molecule topology against QM data and bulk-phase properties, if possible. -Justin Regards, Alex On Tue, Apr 7, 2020 at 5:38 PM Alex wrote: Thanks Justin for the response. Please find below the mdp file. The system is a thin film made out of a epoxy molecule, picture in be below link, with water on top and bottom of the film. I even sometimes have the same issue when I simulate the bulk of this system, I mean a cubic box filled by this molecule and no water. I got the force fields from the latest version of ATB repository by which I have previously done some other simulation for the same molecule. https://drive.google.com/open?id=1tJLxh9jQ2v5DDTrVR8IuQz40B3NN0zlb %mdp--- title= Thin-Film integrator = md dt = 0.002 ; 2 fs ;0.001 1 fs nsteps = 2500 ; 50 ns ;5000 ; 50 ns xtc-precision= 500 ; 1000 ;nstlist = 40 %- ;;in .trr file nstxout = 3000 ; 6000 nstvout = 0 nstfout = 0 ;;in energy file.log nstlog = 2000 ; 4000 nstcalcenergy= 2000 ;4000 nstenergy= 2000 ;4000 ;;in xtc file nstxout-compressed = 0 ;compressed-x-grps= non-Water %- continuation = yes gen-vel = no constraint-algorithm = lincs constraints = h-bonds cutoff-scheme= Verlet coulombtype = PME rcoulomb = 1.4 vdwtype = Cut-off rvdw = 1.4 DispCorr = EnerPres tcoupl= v-rescale tc-grps = system tau-t = 1.5 nhchainlength = 10 ref-t = 298.15 pbc = xyz pcoupl = Parrinello-Rahman Pcoupltype = isotropic tau_p= 2.5 compressibility = 4.5e-5 ref_p= 1.0 refcoord-scaling = com energygrps = thin_film SOL comm-mode= Linear nstcomm = 100 comm-grps= Thin_fiml SOL %- Thank you Alex On Tue, Apr 7, 2020 at 5:06 PM Justin Lemkul wrote: On 4/7/20 5:00 PM, Alex wrote: Dear all, After minimization and equalizations using nvt (v-rescale) and npt (both berendsen and ;Parrinello-Rahman), a simulation of mine could run well for 200 ns using dt =0.001 while it would crash after 3 ns If I used dt = 0.002 with the particles communication fatal error. Fatal error: 2 particles communicated to PME rank 12 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. So, if the system would not be well equlibrated, then I would expect that with dt = 0.001 the simulation wouldn't run well for 200 ns. But I expect that it also crashes for example around 6 ns as the with the dt = 0.002 the simulation last only 3 ns. Any comment that helps to understand the problem would be highly appreciated. Please provide a description of what your system is and a full .mdp file. While most of the time these crashes come from poor equilibration, an inadequately parametrized topology or bad combination/misuse of algorithms can also cause crashes. -Justin -- == Justin A. Lemkul, Ph.D. Assistant Professor Office: 301 Fralin Hall Lab: 303 Engel Hall Virginia Tech Department of Biochemistry 340 West Campus Dr. Blacksburg, VA 24061 jalem...@vt.edu | (540) 231-3129 http://www.thelemkullab.com == -- Gromacs Users mailing list * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists * For (un)subscribe requests visit https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a mail to gmx-users-requ...@gromacs.org. -- == Justin A. Lemkul, Ph.D. Assistant Professor Office: 301 Fralin Hall Lab: 303 Engel Hall Virginia Tech Department of Biochemistry 340 West Campus Dr. Blacksburg, VA 24061 jalem...@vt.edu | (540) 231-3129 http://www.thelemkullab.com == -- Gromacs Users mailing list * Please search the archive at
Re: [gmx-users] dt in mdp
Dear Justin, Any comment please? Regards, Alex On Tue, Apr 7, 2020 at 5:38 PM Alex wrote: > Thanks Justin for the response. > Please find below the mdp file. > The system is a thin film made out of a epoxy molecule, picture in be > below link, with water on top and bottom of the film. I even sometimes have > the same issue when I simulate the bulk of this system, I mean a cubic box > filled by this molecule and no water. > I got the force fields from the latest version of ATB repository by which > I have previously done some other simulation for the same molecule. > > https://drive.google.com/open?id=1tJLxh9jQ2v5DDTrVR8IuQz40B3NN0zlb > > %mdp--- > title= Thin-Film > integrator = md > dt = 0.002 ; 2 fs ;0.001 1 fs > nsteps = 2500 ; 50 ns ;5000 ; 50 ns > xtc-precision= 500 ; 1000 > ;nstlist = 40 > %- > ;;in .trr file > nstxout = 3000 ; 6000 > nstvout = 0 > nstfout = 0 > ;;in energy file.log > nstlog = 2000 ; 4000 > nstcalcenergy= 2000 ;4000 > nstenergy= 2000 ;4000 > ;;in xtc file > nstxout-compressed = 0 > ;compressed-x-grps= non-Water > %- > continuation = yes > gen-vel = no > constraint-algorithm = lincs > constraints = h-bonds > cutoff-scheme= Verlet > coulombtype = PME > rcoulomb = 1.4 > > vdwtype = Cut-off > rvdw = 1.4 > DispCorr = EnerPres > > tcoupl= v-rescale > tc-grps = system > tau-t = 1.5 > nhchainlength = 10 > ref-t = 298.15 > pbc = xyz > > pcoupl = Parrinello-Rahman > Pcoupltype = isotropic > tau_p= 2.5 > compressibility = 4.5e-5 > ref_p= 1.0 > refcoord-scaling = com > energygrps = thin_film SOL > comm-mode= Linear > nstcomm = 100 > comm-grps= Thin_fiml SOL > %- > > Thank you > Alex > > On Tue, Apr 7, 2020 at 5:06 PM Justin Lemkul wrote: > >> >> >> On 4/7/20 5:00 PM, Alex wrote: >> > Dear all, >> > After minimization and equalizations using nvt (v-rescale) and npt (both >> > berendsen and ;Parrinello-Rahman), a simulation of mine could run well >> for >> > 200 ns using dt =0.001 while it would crash after 3 ns If I used dt = >> 0.002 >> > with the particles communication fatal error. >> > >> > Fatal error: >> > 2 particles communicated to PME rank 12 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. >> > >> > So, if the system would not be well equlibrated, then I would expect >> that >> > with dt = 0.001 the simulation wouldn't run well for 200 ns. But I >> expect >> > that it also crashes for example around 6 ns as the with the dt = 0.002 >> the >> > simulation last only 3 ns. >> > >> > Any comment that helps to understand the problem would be highly >> > appreciated. >> >> Please provide a description of what your system is and a full .mdp >> file. While most of the time these crashes come from poor equilibration, >> an inadequately parametrized topology or bad combination/misuse of >> algorithms can also cause crashes. >> >> -Justin >> >> -- >> == >> >> Justin A. Lemkul, Ph.D. >> Assistant Professor >> Office: 301 Fralin Hall >> Lab: 303 Engel Hall >> >> Virginia Tech Department of Biochemistry >> 340 West Campus Dr. >> Blacksburg, VA 24061 >> >> jalem...@vt.edu | (540) 231-3129 >> http://www.thelemkullab.com >> >> == >> >> -- >> Gromacs Users mailing list >> >> * Please search the archive at >> http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before >> posting! >> >> * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists >> >> * For (un)subscribe requests visit >> https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or >> send a mail to gmx-users-requ...@gromacs.org. >> > -- Gromacs Users mailing list * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists * For (un)subscribe requests visit https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a mail to gmx-users-requ...@gromacs.org.
Re: [gmx-users] dt in mdp
Thanks Justin for the response. Please find below the mdp file. The system is a thin film made out of a epoxy molecule, picture in be below link, with water on top and bottom of the film. I even sometimes have the same issue when I simulate the bulk of this system, I mean a cubic box filled by this molecule and no water. I got the force fields from the latest version of ATB repository by which I have previously done some other simulation for the same molecule. https://drive.google.com/open?id=1tJLxh9jQ2v5DDTrVR8IuQz40B3NN0zlb %mdp--- title= Thin-Film integrator = md dt = 0.002 ; 2 fs ;0.001 1 fs nsteps = 2500 ; 50 ns ;5000 ; 50 ns xtc-precision= 500 ; 1000 ;nstlist = 40 %- ;;in .trr file nstxout = 3000 ; 6000 nstvout = 0 nstfout = 0 ;;in energy file.log nstlog = 2000 ; 4000 nstcalcenergy= 2000 ;4000 nstenergy= 2000 ;4000 ;;in xtc file nstxout-compressed = 0 ;compressed-x-grps= non-Water %- continuation = yes gen-vel = no constraint-algorithm = lincs constraints = h-bonds cutoff-scheme= Verlet coulombtype = PME rcoulomb = 1.4 vdwtype = Cut-off rvdw = 1.4 DispCorr = EnerPres tcoupl= v-rescale tc-grps = system tau-t = 1.5 nhchainlength = 10 ref-t = 298.15 pbc = xyz pcoupl = Parrinello-Rahman Pcoupltype = isotropic tau_p= 2.5 compressibility = 4.5e-5 ref_p= 1.0 refcoord-scaling = com energygrps = thin_film SOL comm-mode= Linear nstcomm = 100 comm-grps= Thin_fiml SOL %- Thank you Alex On Tue, Apr 7, 2020 at 5:06 PM Justin Lemkul wrote: > > > On 4/7/20 5:00 PM, Alex wrote: > > Dear all, > > After minimization and equalizations using nvt (v-rescale) and npt (both > > berendsen and ;Parrinello-Rahman), a simulation of mine could run well > for > > 200 ns using dt =0.001 while it would crash after 3 ns If I used dt = > 0.002 > > with the particles communication fatal error. > > > > Fatal error: > > 2 particles communicated to PME rank 12 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. > > > > So, if the system would not be well equlibrated, then I would expect that > > with dt = 0.001 the simulation wouldn't run well for 200 ns. But I expect > > that it also crashes for example around 6 ns as the with the dt = 0.002 > the > > simulation last only 3 ns. > > > > Any comment that helps to understand the problem would be highly > > appreciated. > > Please provide a description of what your system is and a full .mdp > file. While most of the time these crashes come from poor equilibration, > an inadequately parametrized topology or bad combination/misuse of > algorithms can also cause crashes. > > -Justin > > -- > == > > Justin A. Lemkul, Ph.D. > Assistant Professor > Office: 301 Fralin Hall > Lab: 303 Engel Hall > > Virginia Tech Department of Biochemistry > 340 West Campus Dr. > Blacksburg, VA 24061 > > jalem...@vt.edu | (540) 231-3129 > http://www.thelemkullab.com > > == > > -- > Gromacs Users mailing list > > * Please search the archive at > http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before > posting! > > * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists > > * For (un)subscribe requests visit > https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or > send a mail to gmx-users-requ...@gromacs.org. > -- Gromacs Users mailing list * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists * For (un)subscribe requests visit https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a mail to gmx-users-requ...@gromacs.org.
[gmx-users] dt in mdp
Dear all, After minimization and equalizations using nvt (v-rescale) and npt (both berendsen and ;Parrinello-Rahman), a simulation of mine could run well for 200 ns using dt =0.001 while it would crash after 3 ns If I used dt = 0.002 with the particles communication fatal error. Fatal error: 2 particles communicated to PME rank 12 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. So, if the system would not be well equlibrated, then I would expect that with dt = 0.001 the simulation wouldn't run well for 200 ns. But I expect that it also crashes for example around 6 ns as the with the dt = 0.002 the simulation last only 3 ns. Any comment that helps to understand the problem would be highly appreciated. Regards, Alex -- Gromacs Users mailing list * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists * For (un)subscribe requests visit https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a mail to gmx-users-requ...@gromacs.org.
