On 16/08/2012 4:26 PM, jesmin jahan wrote:
Hi Mark,Thanks for your previous reply. I tried to run single point energy simulation with some proteins. I got .log files with content like this: Energies (kJ/mol) Bond Angle Proper Dih. Improper Dih.GB Polarization 1.54109e+04 3.84351e+03 8.47152e+03 3.58425e+02 -1.69666e+04 LJ-14 Coulomb-14 LJ (SR) Coulomb (SR) Potential 4.29664e+03 3.63997e+04 2.22900e+05 -5.18818e+04 2.22832e+05 Kinetic En. Total Energy Temperature Pressure (bar) 1.08443e+09 1.08465e+09 2.73602e+07 0.00000e+00 ....... Computing: M-Number M-Flops % Flops ----------------------------------------------------------------------------- Generalized Born Coulomb 0.005711 0.274 0.2 GB Coulomb + LJ 0.416308 25.395 18.5 Outer nonbonded loop 0.016367 0.164 0.1 1,4 nonbonded interactions 0.008410 0.757 0.6 Born radii (HCT/OBC) 0.439486 80.426 58.5 Born force chain rule 0.439486 6.592 4.8 NS-Pairs 0.943653 19.817 14.4 Reset In Box 0.003179 0.010 0.0 CG-CoM 0.006358 0.019 0.0 Bonds 0.003219 0.190 0.1 Angles 0.005838 0.981 0.7 Propers 0.011273 2.582 1.9 Virial 0.003899 0.070 0.1 Stop-CM 0.003179 0.032 0.0 Calc-Ekin 0.006358 0.172 0.1 ----------------------------------------------------------------------------- Total 137.479 100.0 ----------------------------------------------------------------------------- D O M A I N D E C O M P O S I T I O N S T A T I S T I C S av. #atoms communicated per step for force: 2 x 6859.0 R E A L C Y C L E A N D T I M E A C C O U N T I N G Computing: Nodes Number G-Cycles Seconds % ----------------------------------------------------------------------- Domain decomp. 16 1 0.043 0.0 1.4 Comm. coord. 16 1 0.003 0.0 0.1 Neighbor search 16 1 0.103 0.0 3.5 Force 16 1 1.530 0.5 51.5 Wait + Comm. F 16 1 0.264 0.1 8.9 Write traj. 16 1 0.062 0.0 2.1 Update 16 1 0.001 0.0 0.0 Comm. energies 16 2 0.933 0.3 31.4 Rest 16 0.031 0.0 1.1 ----------------------------------------------------------------------- Total 16 2.970 0.9 100.0 ----------------------------------------------------------------------- NOTE: 31 % of the run time was spent communicating energies, you might want to use the -gcom option of mdrun Parallel run - timing based on wallclock. NODE (s) Real (s) (%) Time: 0.056 0.056 100.0 (Mnbf/s) (GFlops) (ns/day) (hour/ns) Performance: 7.497 2.442 1.535 15.637 >From the log file, it seems, the time includes the time for LJ and Columb Potential Energy. But as I said before, I am only interested to GB-energy times. I am doing a comparative study of GB-energy performance (values vs time) for different molecular dynamic packages.
Since the LJ calculation also needs the distances, GROMACS does them in the same loops and makes no apology for being efficient. :-) If you're really trying to measure the time for the GB energy in isolation, then you will need to construct a different model physics that lacks LJ interactions. Or perhaps you don't really want to measure the time for GB energy in isolation. Depends what you're planning on using the information for, but usually measuring a time representative of the calculation you plan to run later is a good way to avoid having to account for lots of subtleties of different packages.
That's why I was trying to deduct the time for any other extra energy computation time from it. Can anyone tell me how to get the exact time of GB-polarization energy (including Born radii) and excluding the times for any other additional energy (like LJ and Columb etc) from gromacs simutation?
The .tpr you use for the rerun doesn't have to be one that will produce a sensible model physics. If you remove the bonded terms and zero the VDW parameters then the only thing left to compute is the electrostatics, which will give you the time you seek. You'll still potentially have time spent doing neighbour searching, and that is something you need to consider for gauging relative performance of different packages. Again, the times you measure will not be significant unless you run for at least several minutes.
Mark
Thanks, Jesmin On Tue, Aug 14, 2012 at 10:16 AM, jesmin jahan <shraba...@gmail.com> wrote:Thanks Mark for your reply. I was trying to use Single-Point Energy Calculation as you advised in your first reply but for most of the files the simulation failed because I was using the original .pdb files in the mdrun command. Anyways. I really appreciate your help. Thanks again, Jesmin On Tue, Aug 14, 2012 at 1:26 AM, Mark Abraham <mark.abra...@anu.edu.au> wrote:On 14/08/2012 7:38 AM, jesmin jahan wrote:Dear Gromacs Users, I have some questions regarding GB-Polarization Energy Calculation with Gromacs. I will be grateful if someone can help me with the answers. I am trying to calculate GB-Polarization energy for different Protein molecules. I am interested both in energy values with the time required to calculate the Born Radii and Polarization Energy. I am not doing any energy minimization step as the files I am using as input are already minimized. Here is the content of my mdrun.mdp file: constraints = none integrator = md pbc = no dt = 0.001 nsteps = 0 implicit_solvent = GBSA gb_algorithm = HCT sa_algorithm = None And I am using following three steps for all the .pdb files I have: let x is the name of the .pdb file. pdb2gmx -f x.pdb -ter -ignh -ff amber99sb -water none grompp -f mdr.mdp -c conf.gro -p topol.top -o imd.tpr mpirun -np 8 mdrun_mpi -deffnm imd -v -g x.logSo you're not using the advice I gave you about how to calculate single point energies. OK.1 .Now the running time reported by a log file also includes other times. Its also not clear to me whether the time includes the time for Born Radii calculations.The timing breakdown is printed at the end of the .log file. Likely your time is heavily dominated by the GB calculation and communication cost. Born radii calculation are part of the former, and not reported separately. You should not bother with timing measurements unless your run goes for at least several minutes, else your time will be dominated by I/O and setup costs.So, to get the GB-energy time I am doing the following: I am also running a simulation with "implicit_solvent" set to "no" and I am taking the difference of these two (with GB and Without GB). Is that a right approach?No, that measures the weight difference between an apple and an orange, not whether the apple's seeds are heavy.I also want to be sure that it also includes Born-Radii calculation time.It's part of the GB calculation, so it's included in its timing.Is there any other approach to do this? 2. I was trying to run the simulations on 192 cores (16 nodes each with 12 codes). But I got "There is no domain decomposition for 12 nodes that is compatible with the given box and a minimum cell size of 2.90226 nm" error for some pdb files. Can anyone explain what is happening. Is there any restriction on number of nodes can be used?Yes. See discussion linked from http://www.gromacs.org/Documentation/Errors3. I run the simulations with 1 way 96 (8 nodes each with 12 cores). Its not clear to me from the log file whether Gromacs is able to utilize all the 92 cores. It seems, it is using only 8 nodes. Does Gromacs use both shared and distributed memory parallelism?Not at the moment. Look at the top of your .log file for clues about what your configuration is making available to GROMACS. It is likely that mpirun -np 8 makes only 8 MPI processes available to GROMACS. Using more will require you to use your MPI installation correctly (and we can't help with that).4. In the single-point energy calculation "mdrun -s input.tpr -rerun configuration.pdb", is the configuration.pdb mentioned is the original pdb file used on pdb2gmx with -f option? Or its a modified pdb file? I am asking because if I use the original file that does not work always :-(It can be any configuration that matches the .top file you gave to grompp. That's the point - you only need one run input file to compute the energy of any such configuration you later want. The configuration you gave to grompp (or any other tool) doesn't matter.5. Is there any known speedup factor of Gromacs on multicores?That depends on your simulation system, hardware, network and algorithm. Don't bother with fewer than hundreds of atoms per core. Mark -- gmx-users mailing list gmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users * Only plain text messages are allowed! * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/Search before posting! * Please don't post (un)subscribe requests to the list. Use the www interface or send it to gmx-users-requ...@gromacs.org. * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists-- Jesmin Jahan Tithi PhD Student, CS Stony Brook University, NY-11790.
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