Re: [gmx-users] High load imbalance: 31.8%
Hi Anthony, Good choice, your admins should be able to help. Do emphasize when talking to them that you need your job to be placed as compact as possible, on the closest possible set of cores with the tightest possible affinity settings. Cheers, -- Szilárd On Thu, Aug 20, 2015 at 6:12 PM, Nash, Anthony a.n...@ucl.ac.uk wrote: Hi Szilárd Thanks for all of that advice. I’m going to have to take a lot of this up with the Cluster Service Staff. This is a new cluster service I won a grant for, thus not my usual platform which would typically yield an imbalance of somewhere around 0.8% to 2%. Thanks again Anthony On 20/08/2015 16:52, Szilárd Páll pall.szil...@gmail.com wrote: Hi, You're not pinning threads and it seems that you're running on a large SMP machine! Assuming that the 512 threads reported (line 91) is correct that's a 32 socket SMP machine, perhaps an SGI UV? In any case Xeon E5-4xxx is typically deployed in 4-8 socket installations, so your 8 threads will be floating around on a number of CPUs which ruins your performance - and likely contributes to the varying and large load imbalance. My advice: - don't ignore notes/warnings issued by mdrun (line 366, should be on the standard out too), we put quite some though into spamming users only when relevant :) - pin mdrun and/or its threads either with -pin on (and -pinoffset if needed) or with whatever tools your admins provide/recommend [Extras: consider using FFTW even with the Intel compilers it's often faster for our small FFTs than MKL; and GNU iso Intel compiler is often faster too.] Fixing the above issues should not only reduce imbalance but most likely also allow you to gain quite some simulation performance! Let us know if it worked. Cheers, -- Szilárd On Thu, Aug 20, 2015 at 5:08 PM, Nash, Anthony a.n...@ucl.ac.uk wrote: Hi Mark, Many thanks for looking into this. One of the log files (the job hasn’t finished running) is here: https://www.dropbox.com/s/zwrro54yni2uxtn/umb_3_umb.log?dl=0 The system is a soluble collagenase in water with a collagen substrate and two zinc co-factors. There are 287562 atoms in the system. Please let me know if you need to know anything else. Thanks! Anthony On 20/08/2015 11:39, Mark Abraham mark.j.abra...@gmail.com wrote: Hi, In cases like this, it's good to describe what's in your simulation, and share the full .log file on a file-sharing service, so we can see both the things mdrun reports early and late. Mark On Thu, Aug 20, 2015 at 8:22 AM Nash, Anthony a.n...@ucl.ac.uk wrote: Hi all, I appear to have a very high load imbalance on some of my runs. Values starting from approx. 7% up to 31.8% with reported vol min/aver of around 0.6 (I haven¹t found one under half yet). When I look through the .log file at the start of the run I see: Initializing Domain Decomposition on 8 ranks Dynamic load balancing: auto Will sort the charge groups at every domain (re)decomposition Initial maximum inter charge-group distances: two-body bonded interactions: 0.514 nm, LJ-14, atoms 3116 3123 multi-body bonded interactions: 0.429 nm, Proper Dih., atoms 3116 3123 Minimum cell size due to bonded interactions: 0.472 nm Maximum distance for 5 constraints, at 120 deg. angles, all-trans: 0.862 nm Estimated maximum distance required for P-LINCS: 0.862 nm This distance will limit the DD cell size, you can override this with -rcon Using 0 separate PME ranks, as there are too few total ranks for efficient splitting Scaling the initial minimum size with 1/0.8 (option -dds) = 1.25 Optimizing the DD grid for 8 cells with a minimum initial size of 1.077 nm The maximum allowed number of cells is: X 12 Y 12 Z 12 Domain decomposition grid 4 x 2 x 1, separate PME ranks 0 PME domain decomposition: 4 x 2 x 1 Domain decomposition rank 0, coordinates 0 0 0 Using 8 MPI processes Using 1 OpenMP thread per MPI process Having a quick look through the documentation and I see that I should consider implementing the verlet cut-off (which I am) and adjust the number of PME nodes/cut-off and PME grid spacing. Would this simply be a case of throwing more cores at the simulation or must I play around with P-LINCS parameters? Thanks Anthony -- 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
Re: [gmx-users] High load imbalance: 31.8%
Hi, In cases like this, it's good to describe what's in your simulation, and share the full .log file on a file-sharing service, so we can see both the things mdrun reports early and late. Mark On Thu, Aug 20, 2015 at 8:22 AM Nash, Anthony a.n...@ucl.ac.uk wrote: Hi all, I appear to have a very high load imbalance on some of my runs. Values starting from approx. 7% up to 31.8% with reported vol min/aver of around 0.6 (I haven¹t found one under half yet). When I look through the .log file at the start of the run I see: Initializing Domain Decomposition on 8 ranks Dynamic load balancing: auto Will sort the charge groups at every domain (re)decomposition Initial maximum inter charge-group distances: two-body bonded interactions: 0.514 nm, LJ-14, atoms 3116 3123 multi-body bonded interactions: 0.429 nm, Proper Dih., atoms 3116 3123 Minimum cell size due to bonded interactions: 0.472 nm Maximum distance for 5 constraints, at 120 deg. angles, all-trans: 0.862 nm Estimated maximum distance required for P-LINCS: 0.862 nm This distance will limit the DD cell size, you can override this with -rcon Using 0 separate PME ranks, as there are too few total ranks for efficient splitting Scaling the initial minimum size with 1/0.8 (option -dds) = 1.25 Optimizing the DD grid for 8 cells with a minimum initial size of 1.077 nm The maximum allowed number of cells is: X 12 Y 12 Z 12 Domain decomposition grid 4 x 2 x 1, separate PME ranks 0 PME domain decomposition: 4 x 2 x 1 Domain decomposition rank 0, coordinates 0 0 0 Using 8 MPI processes Using 1 OpenMP thread per MPI process Having a quick look through the documentation and I see that I should consider implementing the verlet cut-off (which I am) and adjust the number of PME nodes/cut-off and PME grid spacing. Would this simply be a case of throwing more cores at the simulation or must I play around with P-LINCS parameters? Thanks Anthony -- 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] High load imbalance: 31.8%
Hi Mark, Many thanks for looking into this. One of the log files (the job hasn’t finished running) is here: https://www.dropbox.com/s/zwrro54yni2uxtn/umb_3_umb.log?dl=0 The system is a soluble collagenase in water with a collagen substrate and two zinc co-factors. There are 287562 atoms in the system. Please let me know if you need to know anything else. Thanks! Anthony On 20/08/2015 11:39, Mark Abraham mark.j.abra...@gmail.com wrote: Hi, In cases like this, it's good to describe what's in your simulation, and share the full .log file on a file-sharing service, so we can see both the things mdrun reports early and late. Mark On Thu, Aug 20, 2015 at 8:22 AM Nash, Anthony a.n...@ucl.ac.uk wrote: Hi all, I appear to have a very high load imbalance on some of my runs. Values starting from approx. 7% up to 31.8% with reported vol min/aver of around 0.6 (I haven¹t found one under half yet). When I look through the .log file at the start of the run I see: Initializing Domain Decomposition on 8 ranks Dynamic load balancing: auto Will sort the charge groups at every domain (re)decomposition Initial maximum inter charge-group distances: two-body bonded interactions: 0.514 nm, LJ-14, atoms 3116 3123 multi-body bonded interactions: 0.429 nm, Proper Dih., atoms 3116 3123 Minimum cell size due to bonded interactions: 0.472 nm Maximum distance for 5 constraints, at 120 deg. angles, all-trans: 0.862 nm Estimated maximum distance required for P-LINCS: 0.862 nm This distance will limit the DD cell size, you can override this with -rcon Using 0 separate PME ranks, as there are too few total ranks for efficient splitting Scaling the initial minimum size with 1/0.8 (option -dds) = 1.25 Optimizing the DD grid for 8 cells with a minimum initial size of 1.077 nm The maximum allowed number of cells is: X 12 Y 12 Z 12 Domain decomposition grid 4 x 2 x 1, separate PME ranks 0 PME domain decomposition: 4 x 2 x 1 Domain decomposition rank 0, coordinates 0 0 0 Using 8 MPI processes Using 1 OpenMP thread per MPI process Having a quick look through the documentation and I see that I should consider implementing the verlet cut-off (which I am) and adjust the number of PME nodes/cut-off and PME grid spacing. Would this simply be a case of throwing more cores at the simulation or must I play around with P-LINCS parameters? Thanks Anthony -- 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. -- 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] High load imbalance: 31.8%
Hi, You're not pinning threads and it seems that you're running on a large SMP machine! Assuming that the 512 threads reported (line 91) is correct that's a 32 socket SMP machine, perhaps an SGI UV? In any case Xeon E5-4xxx is typically deployed in 4-8 socket installations, so your 8 threads will be floating around on a number of CPUs which ruins your performance - and likely contributes to the varying and large load imbalance. My advice: - don't ignore notes/warnings issued by mdrun (line 366, should be on the standard out too), we put quite some though into spamming users only when relevant :) - pin mdrun and/or its threads either with -pin on (and -pinoffset if needed) or with whatever tools your admins provide/recommend [Extras: consider using FFTW even with the Intel compilers it's often faster for our small FFTs than MKL; and GNU iso Intel compiler is often faster too.] Fixing the above issues should not only reduce imbalance but most likely also allow you to gain quite some simulation performance! Let us know if it worked. Cheers, -- Szilárd On Thu, Aug 20, 2015 at 5:08 PM, Nash, Anthony a.n...@ucl.ac.uk wrote: Hi Mark, Many thanks for looking into this. One of the log files (the job hasn’t finished running) is here: https://www.dropbox.com/s/zwrro54yni2uxtn/umb_3_umb.log?dl=0 The system is a soluble collagenase in water with a collagen substrate and two zinc co-factors. There are 287562 atoms in the system. Please let me know if you need to know anything else. Thanks! Anthony On 20/08/2015 11:39, Mark Abraham mark.j.abra...@gmail.com wrote: Hi, In cases like this, it's good to describe what's in your simulation, and share the full .log file on a file-sharing service, so we can see both the things mdrun reports early and late. Mark On Thu, Aug 20, 2015 at 8:22 AM Nash, Anthony a.n...@ucl.ac.uk wrote: Hi all, I appear to have a very high load imbalance on some of my runs. Values starting from approx. 7% up to 31.8% with reported vol min/aver of around 0.6 (I haven¹t found one under half yet). When I look through the .log file at the start of the run I see: Initializing Domain Decomposition on 8 ranks Dynamic load balancing: auto Will sort the charge groups at every domain (re)decomposition Initial maximum inter charge-group distances: two-body bonded interactions: 0.514 nm, LJ-14, atoms 3116 3123 multi-body bonded interactions: 0.429 nm, Proper Dih., atoms 3116 3123 Minimum cell size due to bonded interactions: 0.472 nm Maximum distance for 5 constraints, at 120 deg. angles, all-trans: 0.862 nm Estimated maximum distance required for P-LINCS: 0.862 nm This distance will limit the DD cell size, you can override this with -rcon Using 0 separate PME ranks, as there are too few total ranks for efficient splitting Scaling the initial minimum size with 1/0.8 (option -dds) = 1.25 Optimizing the DD grid for 8 cells with a minimum initial size of 1.077 nm The maximum allowed number of cells is: X 12 Y 12 Z 12 Domain decomposition grid 4 x 2 x 1, separate PME ranks 0 PME domain decomposition: 4 x 2 x 1 Domain decomposition rank 0, coordinates 0 0 0 Using 8 MPI processes Using 1 OpenMP thread per MPI process Having a quick look through the documentation and I see that I should consider implementing the verlet cut-off (which I am) and adjust the number of PME nodes/cut-off and PME grid spacing. Would this simply be a case of throwing more cores at the simulation or must I play around with P-LINCS parameters? Thanks Anthony -- 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. -- 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
Re: [gmx-users] High load imbalance: 31.8%
On Thu, Aug 20, 2015 at 5:52 PM, Szilárd Páll pall.szil...@gmail.com wrote: Hi, You're not pinning threads and it seems that you're running on a large SMP machine! Assuming that the 512 threads reported (line 91) is correct that's a 32 socket SMP machine, perhaps an SGI UV? In any case Xeon E5-4xxx is typically deployed in 4-8 socket installations, Correction: I confused the E5-46xx with the E7 series. These are 2-4 socket, it seems. In any case, the 512 threads reported still suggests a large SMP machine. so your 8 threads will be floating around on a number of CPUs which ruins your performance - and likely contributes to the varying and large load imbalance. My advice: - don't ignore notes/warnings issued by mdrun (line 366, should be on the standard out too), we put quite some though into spamming users only when relevant :) - pin mdrun and/or its threads either with -pin on (and -pinoffset if needed) or with whatever tools your admins provide/recommend [Extras: consider using FFTW even with the Intel compilers it's often faster for our small FFTs than MKL; and GNU iso Intel compiler is often faster too.] Fixing the above issues should not only reduce imbalance but most likely also allow you to gain quite some simulation performance! Let us know if it worked. Cheers, -- Szilárd On Thu, Aug 20, 2015 at 5:08 PM, Nash, Anthony a.n...@ucl.ac.uk wrote: Hi Mark, Many thanks for looking into this. One of the log files (the job hasn’t finished running) is here: https://www.dropbox.com/s/zwrro54yni2uxtn/umb_3_umb.log?dl=0 The system is a soluble collagenase in water with a collagen substrate and two zinc co-factors. There are 287562 atoms in the system. Please let me know if you need to know anything else. Thanks! Anthony On 20/08/2015 11:39, Mark Abraham mark.j.abra...@gmail.com wrote: Hi, In cases like this, it's good to describe what's in your simulation, and share the full .log file on a file-sharing service, so we can see both the things mdrun reports early and late. Mark On Thu, Aug 20, 2015 at 8:22 AM Nash, Anthony a.n...@ucl.ac.uk wrote: Hi all, I appear to have a very high load imbalance on some of my runs. Values starting from approx. 7% up to 31.8% with reported vol min/aver of around 0.6 (I haven¹t found one under half yet). When I look through the .log file at the start of the run I see: Initializing Domain Decomposition on 8 ranks Dynamic load balancing: auto Will sort the charge groups at every domain (re)decomposition Initial maximum inter charge-group distances: two-body bonded interactions: 0.514 nm, LJ-14, atoms 3116 3123 multi-body bonded interactions: 0.429 nm, Proper Dih., atoms 3116 3123 Minimum cell size due to bonded interactions: 0.472 nm Maximum distance for 5 constraints, at 120 deg. angles, all-trans: 0.862 nm Estimated maximum distance required for P-LINCS: 0.862 nm This distance will limit the DD cell size, you can override this with -rcon Using 0 separate PME ranks, as there are too few total ranks for efficient splitting Scaling the initial minimum size with 1/0.8 (option -dds) = 1.25 Optimizing the DD grid for 8 cells with a minimum initial size of 1.077 nm The maximum allowed number of cells is: X 12 Y 12 Z 12 Domain decomposition grid 4 x 2 x 1, separate PME ranks 0 PME domain decomposition: 4 x 2 x 1 Domain decomposition rank 0, coordinates 0 0 0 Using 8 MPI processes Using 1 OpenMP thread per MPI process Having a quick look through the documentation and I see that I should consider implementing the verlet cut-off (which I am) and adjust the number of PME nodes/cut-off and PME grid spacing. Would this simply be a case of throwing more cores at the simulation or must I play around with P-LINCS parameters? Thanks Anthony -- 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. -- 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] High load imbalance: 31.8%
Hi Szilárd Thanks for all of that advice. I’m going to have to take a lot of this up with the Cluster Service Staff. This is a new cluster service I won a grant for, thus not my usual platform which would typically yield an imbalance of somewhere around 0.8% to 2%. Thanks again Anthony On 20/08/2015 16:52, Szilárd Páll pall.szil...@gmail.com wrote: Hi, You're not pinning threads and it seems that you're running on a large SMP machine! Assuming that the 512 threads reported (line 91) is correct that's a 32 socket SMP machine, perhaps an SGI UV? In any case Xeon E5-4xxx is typically deployed in 4-8 socket installations, so your 8 threads will be floating around on a number of CPUs which ruins your performance - and likely contributes to the varying and large load imbalance. My advice: - don't ignore notes/warnings issued by mdrun (line 366, should be on the standard out too), we put quite some though into spamming users only when relevant :) - pin mdrun and/or its threads either with -pin on (and -pinoffset if needed) or with whatever tools your admins provide/recommend [Extras: consider using FFTW even with the Intel compilers it's often faster for our small FFTs than MKL; and GNU iso Intel compiler is often faster too.] Fixing the above issues should not only reduce imbalance but most likely also allow you to gain quite some simulation performance! Let us know if it worked. Cheers, -- Szilárd On Thu, Aug 20, 2015 at 5:08 PM, Nash, Anthony a.n...@ucl.ac.uk wrote: Hi Mark, Many thanks for looking into this. One of the log files (the job hasn’t finished running) is here: https://www.dropbox.com/s/zwrro54yni2uxtn/umb_3_umb.log?dl=0 The system is a soluble collagenase in water with a collagen substrate and two zinc co-factors. There are 287562 atoms in the system. Please let me know if you need to know anything else. Thanks! Anthony On 20/08/2015 11:39, Mark Abraham mark.j.abra...@gmail.com wrote: Hi, In cases like this, it's good to describe what's in your simulation, and share the full .log file on a file-sharing service, so we can see both the things mdrun reports early and late. Mark On Thu, Aug 20, 2015 at 8:22 AM Nash, Anthony a.n...@ucl.ac.uk wrote: Hi all, I appear to have a very high load imbalance on some of my runs. Values starting from approx. 7% up to 31.8% with reported vol min/aver of around 0.6 (I haven¹t found one under half yet). When I look through the .log file at the start of the run I see: Initializing Domain Decomposition on 8 ranks Dynamic load balancing: auto Will sort the charge groups at every domain (re)decomposition Initial maximum inter charge-group distances: two-body bonded interactions: 0.514 nm, LJ-14, atoms 3116 3123 multi-body bonded interactions: 0.429 nm, Proper Dih., atoms 3116 3123 Minimum cell size due to bonded interactions: 0.472 nm Maximum distance for 5 constraints, at 120 deg. angles, all-trans: 0.862 nm Estimated maximum distance required for P-LINCS: 0.862 nm This distance will limit the DD cell size, you can override this with -rcon Using 0 separate PME ranks, as there are too few total ranks for efficient splitting Scaling the initial minimum size with 1/0.8 (option -dds) = 1.25 Optimizing the DD grid for 8 cells with a minimum initial size of 1.077 nm The maximum allowed number of cells is: X 12 Y 12 Z 12 Domain decomposition grid 4 x 2 x 1, separate PME ranks 0 PME domain decomposition: 4 x 2 x 1 Domain decomposition rank 0, coordinates 0 0 0 Using 8 MPI processes Using 1 OpenMP thread per MPI process Having a quick look through the documentation and I see that I should consider implementing the verlet cut-off (which I am) and adjust the number of PME nodes/cut-off and PME grid spacing. Would this simply be a case of throwing more cores at the simulation or must I play around with P-LINCS parameters? Thanks Anthony -- 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. -- 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
