1 .TH g_angle 1 "Mon 4 Apr 2011" "" "GROMACS suite, VERSION 4.5.4-dev-20110404-bc5695c"
3 g_angle - calculates distributions and correlations for angles and dihedrals
5 .B VERSION 4.5.4-dev-20110404-bc5695c
9 .BI "\-n" " angle.ndx "
10 .BI "\-od" " angdist.xvg "
11 .BI "\-ov" " angaver.xvg "
12 .BI "\-of" " dihfrac.xvg "
13 .BI "\-ot" " dihtrans.xvg "
14 .BI "\-oh" " trhisto.xvg "
15 .BI "\-oc" " dihcorr.xvg "
16 .BI "\-or" " traj.trr "
18 .BI "\-[no]version" ""
27 .BI "\-binwidth" " real "
28 .BI "\-[no]periodic" ""
29 .BI "\-[no]chandler" ""
30 .BI "\-[no]avercorr" ""
31 .BI "\-acflen" " int "
32 .BI "\-[no]normalize" ""
34 .BI "\-fitfn" " enum "
35 .BI "\-ncskip" " int "
36 .BI "\-beginfit" " real "
37 .BI "\-endfit" " real "
39 \&\fB g_angle\fR computes the angle distribution for a number of angles
40 \&or dihedrals. This way you can check whether your simulation
41 \&is correct. With option \fB \-ov\fR you can plot the average angle of
42 \&a group of angles as a function of time. With the \fB \-all\fR option
43 \&the first graph is the average, the rest are the individual angles.
46 \&With the \fB \-of\fR option, \fB g_angle\fR also calculates the fraction of trans
47 \&dihedrals (only for dihedrals) as function of time, but this is
48 \&probably only fun for a selected few.
51 \&With option \fB \-oc\fR a dihedral correlation function is calculated.
54 \&It should be noted that the index file should contain
55 \&atom\-triples for angles or atom\-quadruplets for dihedrals.
56 \&If this is not the case, the program will crash.
59 \&With option \fB \-or\fR a trajectory file is dumped containing cos and
60 \&sin of selected dihedral angles which subsequently can be used as
61 \&input for a PCA analysis using \fB g_covar\fR.
65 Trajectory: xtc trr trj gro g96 pdb cpt
67 .BI "\-n" " angle.ndx"
71 .BI "\-od" " angdist.xvg"
75 .BI "\-ov" " angaver.xvg"
79 .BI "\-of" " dihfrac.xvg"
83 .BI "\-ot" " dihtrans.xvg"
87 .BI "\-oh" " trhisto.xvg"
91 .BI "\-oc" " dihcorr.xvg"
95 .BI "\-or" " traj.trr"
97 Trajectory in portable xdr format
101 Print help info and quit
103 .BI "\-[no]version" "no "
104 Print version info and quit
106 .BI "\-nice" " int" " 19"
109 .BI "\-b" " time" " 0 "
110 First frame (ps) to read from trajectory
112 .BI "\-e" " time" " 0 "
113 Last frame (ps) to read from trajectory
115 .BI "\-dt" " time" " 0 "
116 Only use frame when t MOD dt = first time (ps)
119 View output \fB .xvg\fR, \fB .xpm\fR, \fB .eps\fR and \fB .pdb\fR files
121 .BI "\-xvg" " enum" " xmgrace"
122 xvg plot formatting: \fB xmgrace\fR, \fB xmgr\fR or \fB none\fR
124 .BI "\-type" " enum" " angle"
125 Type of angle to analyse: \fB angle\fR, \fB dihedral\fR, \fB improper\fR or \fB ryckaert\-bellemans\fR
127 .BI "\-[no]all" "no "
128 Plot all angles separately in the averages file, in the order of appearance in the index file.
130 .BI "\-binwidth" " real" " 1 "
131 binwidth (degrees) for calculating the distribution
133 .BI "\-[no]periodic" "yes "
134 Print dihedral angles modulo 360 degrees
136 .BI "\-[no]chandler" "no "
137 Use Chandler correlation function (N[trans] = 1, N[gauche] = 0) rather than cosine correlation function. Trans is defined as phi \-60 or phi 60.
139 .BI "\-[no]avercorr" "no "
140 Average the correlation functions for the individual angles/dihedrals
142 .BI "\-acflen" " int" " \-1"
143 Length of the ACF, default is half the number of frames
145 .BI "\-[no]normalize" "yes "
148 .BI "\-P" " enum" " 0"
149 Order of Legendre polynomial for ACF (0 indicates none): \fB 0\fR, \fB 1\fR, \fB 2\fR or \fB 3\fR
151 .BI "\-fitfn" " enum" " none"
152 Fit function: \fB none\fR, \fB exp\fR, \fB aexp\fR, \fB exp_exp\fR, \fB vac\fR, \fB exp5\fR, \fB exp7\fR, \fB exp9\fR or \fB erffit\fR
154 .BI "\-ncskip" " int" " 0"
155 Skip N points in the output file of correlation functions
157 .BI "\-beginfit" " real" " 0 "
158 Time where to begin the exponential fit of the correlation function
160 .BI "\-endfit" " real" " \-1 "
161 Time where to end the exponential fit of the correlation function, \-1 is until the end
164 \- Counting transitions only works for dihedrals with multiplicity 3
169 More information about \fBGROMACS\fR is available at <\fIhttp://www.gromacs.org/\fR>.