1 .TH g_sgangle 1 "Thu 16 Oct 2008"
3 g_sgangle - computes the angle and distance between two groups
10 .BI "-s" " topol.tpr "
11 .BI "-oa" " sg_angle.xvg "
12 .BI "-od" " sg_dist.xvg "
13 .BI "-od1" " sg_dist1.xvg "
14 .BI "-od2" " sg_dist2.xvg "
25 Compute the angle and distance between two groups.
26 The groups are defined by a number of atoms given in an index file and
27 may be two or three atoms in size.
28 If -one is set, only one group should be specified in the index
29 file and the angle between this group at time 0 and t will be computed.
30 The angles calculated depend on the order in which the atoms are
31 given. Giving for instance 5 6 will rotate the vector 5-6 with
32 180 degrees compared to giving 6 5.
34 If three atoms are given,
35 the normal on the plane spanned by those three atoms will be
36 calculated, using the formula P1P2 x P1P3.
37 The cos of the angle is calculated, using the inproduct of the two
41 Here is what some of the file options do:
43 -oa: Angle between the two groups specified in the index file. If a group contains three atoms the normal to the plane defined by those three atoms will be used. If a group contains two atoms, the vector defined by those two atoms will be used.
45 -od: Distance between two groups. Distance is taken from the center of one group to the center of the other group.
47 -od1: If one plane and one vector is given, the distances for each of the atoms from the center of the plane is given seperately.
49 -od2: For two planes this option has no meaning.
53 Trajectory: xtc trr trj gro g96 pdb cpt
61 Run input file: tpr tpb tpa
63 .BI "-oa" " sg_angle.xvg"
67 .BI "-od" " sg_dist.xvg"
71 .BI "-od1" " sg_dist1.xvg"
75 .BI "-od2" " sg_dist2.xvg"
81 Print help info and quit
83 .BI "-nice" " int" " 19"
86 .BI "-b" " time" " 0 "
87 First frame (ps) to read from trajectory
89 .BI "-e" " time" " 0 "
90 Last frame (ps) to read from trajectory
92 .BI "-dt" " time" " 0 "
93 Only use frame when t MOD dt = first time (ps)
96 View output xvg, xpm, eps and pdb files
98 .BI "-[no]xvgr" "yes "
99 Add specific codes (legends etc.) in the output xvg files for the xmgrace program
102 Only one group compute angle between vector at time zero and time t
105 Use the Z-axis as reference