> On 13/11/2010 4:07 AM, sa wrote: > > Dear All, > > > > I would like to compute the average 2D density distribution of the > > water around 6 peptides aggregated in the cluster within the > > simulation box with gromacs, for that I think that g_densmap is the > > the good tool (correct ?). > > > > However it is not very clear for how to use g_densmap. Below the > > command I used with g_densmap (ver GMX 4.5.3) > > > > g_densmap_mpi -f ./TRAJ/XTC/6_Pep_Urea_Pref_All.xtc -s > > ./TRAJ/TPR/em.tpr -bin 0.02 -amax 30 -rmax 30 -b 0 -e 80000 -o > > 6_Peptide_53A6_densmap.xpm -od 6_Peptide_53A6_densmap.dat > > > > When I use the above command, g_densmap asks me to choose two groups > > to define the axis and an analysis group: > > > > Reading file ./TRAJ/TPR/em.tpr, VERSION 4.5.1 (single precision) > > Reading file ./TRAJ/TPR/em.tpr, VERSION 4.5.1 (single precision) > > Select two groups to define the axis and an analysis group > > Group 0 ( System) has 86359 elements > > Group 1 ( Protein) has 546 elements > > Group 2 ( Protein-H) has 396 elements > > Group 3 ( C-alpha) has 48 elements > > Group 4 ( Backbone) has 144 elements > > Group 5 ( MainChain) has 192 elements > > Group 6 ( MainChain+Cb) has 234 elements > > Group 7 ( MainChain+H) has 246 elements > > Group 8 ( SideChain) has 300 elements > > Group 9 ( SideChain-H) has 204 elements > > Group 10 ( Prot-Masses) has 546 elements > > Group 11 ( non-Protein) has 85813 elements > > Group 12 ( Other) has 17320 elements > > Group 13 ( URE) has 17320 elements > > Group 14 ( CL) has 6 elements > > Group 15 ( Water) has 68487 elements > > Group 16 ( SOL) has 68487 elements > > Group 17 ( non-Water) has 17872 elements > > Group 18 ( Ion) has 6 elements > > Group 19 ( URE) has 17320 elements > > Group 20 ( CL) has 6 elements > > Group 21 ( Water_and_ions) has 68493 elements > > Select a group: 1 > > Selected 1: 'Protein' > > Select a group: 16 > > Selected 16: 'SOL' > > Select a group: 16 > > Selected 16: 'SOL' > > > > I chose protein and SOL, the program ask me to choose a third group > > (?) What to choose ? > > Doesn't g_densmap -h explain the three groups? >
Yes I have read the help of the tool but it is not clear to me why i have to choose three groups since i want to compute the water density map around my peptides (-> two groups) > > > I choose SOL again, the program computes something but i can not > > inspect the results are what i want since no xpm is generated by > > g_densmap (is this a bug ?) > > Probably badly-formed input is silently breaking something somewhere. > I don't understand your response since with the above command and -o argument show that an xpm with the name "6_Peptide_53A6_densmap.xpm" should appear :-) G R O M A C S (-: Gnomes, ROck Monsters And Chili Sauce :-) VERSION 4.5.3 (-: Written by Emile Apol, Rossen Apostolov, Herman J.C. Berendsen, Aldert van Buuren, Pär Bjelkmar, Rudi van Drunen, Anton Feenstra, Gerrit Groenhof, Peter Kasson, Per Larsson, Pieter Meulenhoff, Teemu Murtola, Szilard Pall, Sander Pronk, Roland Schulz, Michael Shirts, Alfons Sijbers, Peter Tieleman, Berk Hess, David van der Spoel, and Erik Lindahl. Copyright (c) 1991-2000, University of Groningen, The Netherlands. Copyright (c) 2001-2010, The GROMACS development team at Uppsala University & The Royal Institute of Technology, Sweden. check out http://www.gromacs.org for more information. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. :-) /work/taulier01/gromacs-4.5.3/bin/g_densmap_mpi (-: Option Filename Type Description ------------------------------------------------------------ -f ./TRAJ/XTC/6_Pep_Urea_Pref_All.xtc Input Trajectory: xtc trr trj gro g96 pdb cpt -s ./TRAJ/TPR/em.tpr Input, Opt! Structure+mass(db): tpr tpb tpa gro g96 pdb -n index.ndx Input, Opt. Index file -od 6_Peptide_53A6_densmap.dat Output, Opt! Generic data file -o 6_Peptide_53A6_densmap.xpm Output X PixMap compatible matrix file Stefane > Mark > > > > >
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