[gmx-users] meaning of results of g_hbond -ac
Dear gmxers, By running the command g_hbond -ac, a resulting .xvg file is generated, which is attached below. In that file, there are five columns. I guess that, the first column is time, the second the HB autocorrelation function. But what are the other columns denoted by s1, s2, s3? Thanks a lot for any reply. Yours sincerely, Chaofu Wu # This file was created Wed Jul 17 09:49:34 2013 # by the following command: # g_hbond -f iconf.xtc -s conf.tpr -n -ac ihbac2.xvg # # g_hbond is part of G R O M A C S: # # GROtesk MACabre and Sinister # @title "Hydrogen Bond Autocorrelation" @xaxis label "Time (ps)" @yaxis label "C(t)" @TYPE xy @ view 0.15, 0.15, 0.75, 0.85 @ legend on @ legend box on @ legend loctype view @ legend 0.78, 0.8 @ legend length 2 @ s0 legend "Ac\sfin sys\v{}\z{}(t)" @ s1 legend "Ac(t)" @ s2 legend "Cc\scontact,hb\v{}\z{}(t)" @ s3 legend "-dAc\sfs\v{}\z{}/dt" 0 1 1 -5.79228e-110.902311 1 0.09955770.1001860.1345570.455234 2 0.0895326 0.09016760.126435 0.00815676 3 0.0832442 0.08388360.123311 0.00541426 4 0.0787041 0.07934660.117936 0.00376486 5 0.0757145 0.07635910.116489 0.00198866 6 0.0747267 0.07537210.112655 0.00177937 7 0.0721557 0.07280290.109565 0.00255146 8 0.0696238 0.07027270.107288 0.00241577 9 0.0673242 0.06797470.106287 0.00157028 10 0.0664832 0.06713430.104746 0.0014926 110.064339 0.06499160.101947 0.00148105 12 0.0635211 0.0641743 0.0991141 0.00131835 13 0.0617023 0.06235670.101322 0.00147757 140.060566 0.0612212 0.0965892 0.000719808 . -- 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 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
[gmx-users] How to modify the code g_hbond to analyze the non-traditional hydrogen bonds like C-H...O
Dear gmxers, I want to analyze the non-traditional hydrogen bonds like C-H...O. To my best knowledge, the g_hbond code can be used for traditional hydrogen bonds but not for our case. One possible solution is to modify the g_hbond code to include the non-traditional hydrogen bonds. However, the code is too long and too complex to understand for me, a non-programmer. Could you give me hints to cope with this, please? Thank you very much for any replies! Yours sincerely, Chaofu Wu -- 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 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
[gmx-users] How to restrain dihedral angles to reserve the tacticity?
Dear gmxers, I try to reserve the tacticity of polymer chains during the MD simulations. By searching this mail-list, I find that to restrain dihedral angles provides a way to realize it. However, what dihedral angles should I restrain? For example, a polymer has a monomer with a chiral carbon C1 and a non-chiral carbon C2 on the main chain, and two different side groups (i.e. R1 and R2) are attached to C1. Could you give me some hints, please? Thanks a lot for any reply to this letter. Yours sincerely, Chaofu Wu -- 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 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
[gmx-users] position restrained energy minimization
Dear gmxers, As is well-known, molecular dynamics can be implemented with position restrained in gromacs. Now I want to ensure whether energy minimization can also be performed with position restrained. Thanks for any reply to this letter. Chaofu Wu -- 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 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
[gmx-users] difference between the tabulated and Cut-off Electicstatics potentials
Dear gmxers, I am trying to perform two separate const-NPT MD simulations using tablulated and Cut-off Electrostatics potentials. I find that for the two cases the density of system is stablized at different values (1200 vs. 1400 g/cm3). Since the partial charges are all zeros in the top files, I assume the two potentials generate same results. But why not as expected? Could you please give me some hints? Yours sincerely, Chaofu Wu -- 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 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
[gmx-users] Some tips for decreasing CPU time for mdrun -rerun
Dear gmxers, I have generated MD simulation trajectory using gmx, and now I want to recalculate the energies and forces for the older trajectory by excluding interactions between two defined groups. Therefore, the older trajectory is used as one input option for mdrun through -rerun. In my opinions, the newer run shoud much quicker than the older one since only saved frames and less interactions are employed in this calculation. However, I find that the speed is almost same. How to decreasing CPU time for mdrun -rerun? I think I must have missed something. Could you please give me some hints? Thank you a lot for any reply. Yours sincerely, Chaofu Wu -- 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 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
[gmx-users] Automatic calculations of forces in tabulated potentials?
Dear gmxers, Can the forces F(r) be calculated automatically from the potentials E(r) so that they can be replaced initially by zeros in the tabulated potentials? Thank you for any reply. Yours sincerely, Chaofu Wu -- 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 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
[gmx-users] puzzling about ffnonbonded.itp
Dear gmxers, While I try to make one customed force field by studying some existing force fields, I find that bond_type and at.num defining [atomtypes ] in the ffnonbonded.itp are included in some force fields (i.e. oplsaa), but not in other force fields (i.e gmx). I wonder how gmx identifies the difference and choose the correct parameters from them. Could you please expain this in details? Thank you very much for any reply. Yours sincerely, Chaofu Wu -- 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 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
[gmx-users] What is gbsa.itp in oplsaa of gmx4.5.5?
Dear gmxers, I am puzzling about the gbsa.itp file as listed below. What does each item mean? Could you please explain it? ;atype sar st pi gbr hct opls_102 0.16 1 1.215 0.1625 0.79 ; N (RNH3+) Yours sincerely, Chaofu Wu -- 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 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
[gmx-users] How to constrain some angles?
Dear gmxers, For some purpose, I want to constrain some angles. Note that it is "some" but not "all", and "constrain" but not "restrain". How to do with it? Thanks a lot for any reply. Chaofu Wu -- gmx-users mailing listgmx-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
[gmx-users] How to speed up equilibrating the density of bulk system?
Dear gmxers, I am trying to generate one polymer melt from one big enough box using NPT MD in gmx. I find that the density of system varies very slow. Could you please give me some hints about how to speed up this process? Thanks a lot for any reply. Yours sincerely, Chaofu Wu. -- gmx-users mailing listgmx-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