1 .TH g_sgangle 1 "Mon 4 Apr 2011" "" "GROMACS suite, VERSION 4.5.4-dev-20110404-bc5695c"
3 g_sgangle - computes the angle and distance between two groups
5 .B VERSION 4.5.4-dev-20110404-bc5695c
9 .BI "\-n" " index.ndx "
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 "
16 .BI "\-[no]version" ""
26 \&Compute the angle and distance between two groups.
27 \&The groups are defined by a number of atoms given in an index file and
28 \&may be two or three atoms in size.
29 \&If \fB \-one\fR is set, only one group should be specified in the index
30 \&file and the angle between this group at time 0 and t will be computed.
31 \&The angles calculated depend on the order in which the atoms are
32 \&given. Giving, for instance, 5 6 will rotate the vector 5\-6 with
33 \&180 degrees compared to giving 6 5.
35 If three atoms are given,
36 \&the normal on the plane spanned by those three atoms will be
37 \&calculated, using the formula P1P2 x P1P3.
38 \&The cos of the angle is calculated, using the inproduct of the two
42 \&Here is what some of the file options do:
44 \&\fB \-oa\fR: 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.
46 \&\fB \-od\fR: Distance between two groups. Distance is taken from the center of one group to the center of the other group.
48 \&\fB \-od1\fR: If one plane and one vector is given, the distances for each of the atoms from the center of the plane is given separately.
50 \&\fB \-od2\fR: For two planes this option has no meaning.
54 Trajectory: xtc trr trj gro g96 pdb cpt
56 .BI "\-n" " index.ndx"
60 .BI "\-s" " topol.tpr"
62 Run input file: tpr tpb tpa
64 .BI "\-oa" " sg_angle.xvg"
68 .BI "\-od" " sg_dist.xvg"
72 .BI "\-od1" " sg_dist1.xvg"
76 .BI "\-od2" " sg_dist2.xvg"
82 Print help info and quit
84 .BI "\-[no]version" "no "
85 Print version info and quit
87 .BI "\-nice" " int" " 19"
90 .BI "\-b" " time" " 0 "
91 First frame (ps) to read from trajectory
93 .BI "\-e" " time" " 0 "
94 Last frame (ps) to read from trajectory
96 .BI "\-dt" " time" " 0 "
97 Only use frame when t MOD dt = first time (ps)
100 View output \fB .xvg\fR, \fB .xpm\fR, \fB .eps\fR and \fB .pdb\fR files
102 .BI "\-xvg" " enum" " xmgrace"
103 xvg plot formatting: \fB xmgrace\fR, \fB xmgr\fR or \fB none\fR
105 .BI "\-[no]one" "no "
106 Only one group compute angle between vector at time zero and time t
109 Use the \fI z\fR\-axis as reference
114 More information about \fBGROMACS\fR is available at <\fIhttp://www.gromacs.org/\fR>.