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g_velaccMain Table of Contents |
VERSION 4.5
Thu 26 Aug 2010
| VERSION 4.5 |
g_velacc computes the velocity autocorrelation function. When the -m option is used, the momentum autocorrelation function is calculated.
With option -mol the velocity autocorrelation function of molecules is calculated. In this case the index group should consist of molecule numbers instead of atom numbers.
| option | filename | type | description |
|---|---|---|---|
| -f | traj.trr | Input | Full precision trajectory: trr trj cpt |
| -s | topol.tpr | Input, Opt. | Structure+mass(db): tpr tpb tpa gro g96 pdb |
| -n | index.ndx | Input, Opt. | Index file |
| -o | vac.xvg | Output | xvgr/xmgr file |
| option | type | default | description |
|---|---|---|---|
| -[no]h | gmx_bool | no | Print help info and quit |
| -[no]version | gmx_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 | gmx_bool | no | View output xvg, xpm, eps and pdb files |
| -xvg | enum | xmgrace | xvg plot formatting: xmgrace, xmgr or none |
| -[no]m | gmx_bool | no | Calculate the momentum autocorrelation function |
| -[no]mol | gmx_bool | no | Calculate the velocity acf of molecules |
| -acflen | int | -1 | Length of the ACF, default is half the number of frames |
| -[no]normalize | gmx_bool | yes | Normalize ACF |
| -P | enum | 0 | Order of Legendre polynomial for ACF (0 indicates none): 0, 1, 2 or 3 |
| -fitfn | enum | none | Fit function: none, exp, aexp, exp_exp, vac, exp5, exp7 or exp9 |
| -ncskip | int | 0 | Skip N points in the output file of correlation functions |
| -beginfit | real | 0 | Time where to begin the exponential fit of the correlation function |
| -endfit | real | -1 | Time where to end the exponential fit of the correlation function, -1 is until the end |