1 .TH g_sdf 1 "Thu 16 Oct 2008"
3 g_sdf - calculates the spatial distribution function (faster than g_spatial)
10 .BI "-s" " topol.tpr "
11 .BI "-o" " gom_plt.dat "
12 .BI "-r" " refmol.gro "
19 .BI "-triangle" " vector "
20 .BI "-dtri" " vector "
22 .BI "-grid" " vector "
24 g_sdf calculates the spatial distribution function (SDF) of a set of atoms
25 within a coordinate system defined by three atoms. There is single body,
26 two body and three body SDF implemented (select with option -mode).
27 In the single body case the local coordinate system is defined by using
28 a triple of atoms from one single molecule, for the two and three body case
29 the configurations are dynamically searched complexes of two or three
30 molecules (or residues) meeting certain distance consitions (see below).
33 The program needs a trajectory, a GROMACS run input file and an index
35 You have to setup 4 groups in the index file before using g_sdf:
38 The first three groups are used to define the SDF coordinate system.
39 The programm will dynamically generate the atom tripels according to
41 In -mode 1 the triples will be just the 1st, 2nd, 3rd, ... atoms from
42 groups 1, 2 and 3. Hence the nth entries in groups 1, 2 and 3 must be from the
43 same residue. In -mode 2 the triples will be 1st, 2nd, 3rd, ... atoms from
44 groups 1 and 2 (with the nth entries in groups 1 and 2 having the same res-id).
45 For each pair from groups 1 and 2 group 3 is searched for an atom meeting the
46 distance conditions set with -triangle and -dtri relative to atoms 1 and 2. In
47 -mode 3 for each atom in group 1 group 2 is searched for an atom meeting the
48 distance condition and if a pair is found group 3 is searched for an atom
49 meeting the further conditions. The triple will only be used if all three atoms
50 have different res-id's.
53 The local coordinate system is always defined using the following scheme:
54 Atom 1 will be used as the point of origin for the SDF. Atom 1 and 2 will define the principle axis (Z) of the coordinate system.
55 The other two axis will be defined inplane (Y) and normal (X) to the plane through
56 Atoms 1, 2 and 3. The fourth group
57 contains the atoms for which the SDF will be evaluated.
60 For -mode 2 and 3 you have to define the distance conditions for the
61 2 resp. 3 molecule complexes to be searched for using -triangle and -dtri.
64 The SDF will be sampled in cartesian coordinates.
65 Use '-grid x y z' to define the size of the SDF grid around the
67 The Volume of the SDF grid will be V=x*y*z (nm3). Use -bin to set the binwidth for grid.
70 The output will be a binary 3D-grid file (gom_plt.dat) in the .plt format that can be be
71 read directly by gOpenMol.
72 The option -r will generate a .gro file with the reference molecule(s) transfered to
73 the SDF coordinate system. Load this file into gOpenMol and display the
74 SDF as a contour plot (see http://www.csc.fi/gopenmol/index.phtml for
75 further documentation).
78 For further information about SDF's have a look at: A. Vishnyakov, JPC A, 105,
79 2001, 1702 and the references cited within.
83 Trajectory: xtc trr trj gro g96 pdb cpt
91 Structure+mass(db): tpr tpb tpa gro g96 pdb
93 .BI "-o" " gom_plt.dat"
97 .BI "-r" " refmol.gro"
99 Structure file: gro g96 pdb
103 Print help info and quit
105 .BI "-nice" " int" " 19"
108 .BI "-b" " time" " 0 "
109 First frame (ps) to read from trajectory
111 .BI "-e" " time" " 0 "
112 Last frame (ps) to read from trajectory
114 .BI "-dt" " time" " 0 "
115 Only use frame when t MOD dt = first time (ps)
117 .BI "-mode" " int" " 1"
118 SDF in [1,2,3] particle mode
120 .BI "-triangle" " vector" " 0 0 0"
121 r(1,3), r(2,3), r(1,2)
123 .BI "-dtri" " vector" " 0.03 0.03 0.03"
124 dr(1,3), dr(2,3), dr(1,2)
126 .BI "-bin" " real" " 0.05 "
127 Binwidth for the 3D-grid (nm)
129 .BI "-grid" " vector" " 1 1 1"
130 Size of the 3D-grid (nm,nm,nm)