| VERSION 4.6.1 |
Compute the angle and distance between two groups. The groups are defined by a number of atoms given in an index file and may be two or three atoms in size. If -one is set, only one group should be specified in the index file and the angle between this group at time 0 and t will be computed. The angles calculated depend on the order in which the atoms are given. Giving, for instance, 5 6 will rotate the vector 5-6 with 180 degrees compared to giving 6 5.
If three atoms are given, the normal on the plane spanned by those three atoms will be calculated, using the formula P1P2 x P1P3. The cos of the angle is calculated, using the inproduct of the two normalized vectors.
Here is what some of the file options do:
-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.
-od: Distance between two groups. Distance is taken from the center of one group to the center of the other group.
-od1: If one plane and one vector is given, the distances for each of the atoms from the center of the plane is given separately.
-od2: For two planes this option has no meaning.
option | filename | type | description |
---|---|---|---|
-f | traj.xtc | Input | Trajectory: xtc trr trj gro g96 pdb cpt |
-n | index.ndx | Input | Index file |
-s | topol.tpr | Input | Run input file: tpr tpb tpa |
-oa | sg_angle.xvg | Output | xvgr/xmgr file |
-od | sg_dist.xvg | Output, Opt. | xvgr/xmgr file |
-od1 | sg_dist1.xvg | Output, Opt. | xvgr/xmgr file |
-od2 | sg_dist2.xvg | Output, Opt. | xvgr/xmgr file |
option | type | default | description |
---|---|---|---|
-[no]h | bool | no | Print help info and quit |
-[no]version | bool | no | Print version info and quit |
-nice | int | 19 | Set the nicelevel |
-b | time | 0 | First frame (ps) to read from trajectory |
-e | time | 0 | Last frame (ps) to read from trajectory |
-dt | time | 0 | Only use frame when t MOD dt = first time (ps) |
-[no]w | bool | no | View output .xvg, .xpm, .eps and .pdb files |
-xvg | enum | xmgrace | xvg plot formatting: xmgrace, xmgr or none |
-[no]one | bool | no | Only one group compute angle between vector at time zero and time t |
-[no]z | bool | no | Use the |