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4 <String Name="Help string">SYNOPSIS
6 gmx [-s [<.tpr>]] [-cpi [<.cpt>]] [-table [<.xvg>]] [-tablep [<.xvg>]]
7 [-tableb [<.xvg> [...]]] [-rerun [<.xtc/.trr/...>]] [-ei [<.edi>]]
8 [-multidir [<dir> [...]]] [-awh [<.xvg>]] [-membed [<.dat>]]
9 [-mp [<.top>]] [-mn [<.ndx>]] [-o [<.trr/.cpt/...>]] [-x [<.xtc/.tng>]]
10 [-cpo [<.cpt>]] [-c [<.gro/.g96/...>]] [-e [<.edr>]] [-g [<.log>]]
11 [-dhdl [<.xvg>]] [-field [<.xvg>]] [-tpi [<.xvg>]] [-tpid [<.xvg>]]
12 [-eo [<.xvg>]] [-px [<.xvg>]] [-pf [<.xvg>]] [-ro [<.xvg>]]
13 [-ra [<.log>]] [-rs [<.log>]] [-rt [<.log>]] [-mtx [<.mtx>]]
14 [-if [<.xvg>]] [-swap [<.xvg>]] [-deffnm <string>] [-xvg <enum>]
15 [-dd <vector>] [-ddorder <enum>] [-npme <int>] [-nt <int>] [-ntmpi <int>]
16 [-ntomp <int>] [-ntomp_pme <int>] [-pin <enum>] [-pinoffset <int>]
17 [-pinstride <int>] [-gpu_id <string>] [-gputasks <string>] [-[no]ddcheck]
18 [-rdd <real>] [-rcon <real>] [-dlb <enum>] [-dds <real>] [-nb <enum>]
19 [-nstlist <int>] [-[no]tunepme] [-pme <enum>] [-pmefft <enum>]
20 [-bonded <enum>] [-[no]v] [-pforce <real>] [-[no]reprod] [-cpt <real>]
21 [-[no]cpnum] [-[no]append] [-nsteps <int>] [-maxh <real>] [-replex <int>]
22 [-nex <int>] [-reseed <int>]
26 [THISMODULE] is the main computational chemistry engine within GROMACS.
27 Obviously, it performs Molecular Dynamics simulations, but it can also perform
28 Stochastic Dynamics, Energy Minimization, test particle insertion or
29 (re)calculation of energies. Normal mode analysis is another option. In this
30 case mdrun builds a Hessian matrix from single conformation. For usual Normal
31 Modes-like calculations, make sure that the structure provided is properly
32 energy-minimized. The generated matrix can be diagonalized by [gmx-nmeig].
34 The mdrun program reads the run input file (-s) and distributes the topology
35 over ranks if needed. mdrun produces at least four output files. A single log
36 file (-g) is written. The trajectory file (-o), contains coordinates,
37 velocities and optionally forces. The structure file (-c) contains the
38 coordinates and velocities of the last step. The energy file (-e) contains
39 energies, the temperature, pressure, etc, a lot of these things are also
40 printed in the log file. Optionally coordinates can be written to a compressed
43 The option -dhdl is only used when free energy calculation is turned on.
45 Running mdrun efficiently in parallel is a complex topic, many aspects of
46 which are covered in the online User Guide. You should look there for
47 practical advice on using many of the options available in mdrun.
49 ED (essential dynamics) sampling and/or additional flooding potentials are
50 switched on by using the -ei flag followed by an .edi file. The .edi file can
51 be produced with the make_edi tool or by using options in the essdyn menu of
52 the WHAT IF program. mdrun produces a .xvg output file that contains
53 projections of positions, velocities and forces onto selected eigenvectors.
55 When user-defined potential functions have been selected in the .mdp file the
56 -table option is used to pass mdrun a formatted table with potential
57 functions. The file is read from either the current directory or from the
58 GMXLIB directory. A number of pre-formatted tables are presented in the GMXLIB
59 dir, for 6-8, 6-9, 6-10, 6-11, 6-12 Lennard-Jones potentials with normal
60 Coulomb. When pair interactions are present, a separate table for pair
61 interaction functions is read using the -tablep option.
63 When tabulated bonded functions are present in the topology, interaction
64 functions are read using the -tableb option. For each different tabulated
65 interaction type used, a table file name must be given. For the topology to
66 work, a file name given here must match a character sequence before the file
67 extension. That sequence is: an underscore, then a 'b' for bonds, an 'a' for
68 angles or a 'd' for dihedrals, and finally the matching table number index
69 used in the topology. Note that, these options are deprecated, and in future
70 will be available via grompp.
72 The options -px and -pf are used for writing pull COM coordinates and forces
73 when pulling is selected in the .mdp file.
75 The option -membed does what used to be g_membed, i.e. embed a protein into a
76 membrane. This module requires a number of settings that are provided in a
77 data file that is the argument of this option. For more details in membrane
78 embedding, see the documentation in the user guide. The options -mn and -mp
79 are used to provide the index and topology files used for the embedding.
81 The option -pforce is useful when you suspect a simulation crashes due to too
82 large forces. With this option coordinates and forces of atoms with a force
83 larger than a certain value will be printed to stderr. It will also terminate
84 the run when non-finite forces are present.
86 Checkpoints containing the complete state of the system are written at regular
87 intervals (option -cpt) to the file -cpo, unless option -cpt is set to -1. The
88 previous checkpoint is backed up to state_prev.cpt to make sure that a recent
89 state of the system is always available, even when the simulation is
90 terminated while writing a checkpoint. With -cpnum all checkpoint files are
91 kept and appended with the step number. A simulation can be continued by
92 reading the full state from file with option -cpi. This option is intelligent
93 in the way that if no checkpoint file is found, GROMACS just assumes a normal
94 run and starts from the first step of the .tpr file. By default the output
95 will be appending to the existing output files. The checkpoint file contains
96 checksums of all output files, such that you will never loose data when some
97 output files are modified, corrupt or removed. There are three scenarios with
100 * no files with matching names are present: new output files are written
102 * all files are present with names and checksums matching those stored in the
103 checkpoint file: files are appended
105 * otherwise no files are modified and a fatal error is generated
107 With -noappend new output files are opened and the simulation part number is
108 added to all output file names. Note that in all cases the checkpoint file
109 itself is not renamed and will be overwritten, unless its name does not match
112 With checkpointing the output is appended to previously written output files,
113 unless -noappend is used or none of the previous output files are present
114 (except for the checkpoint file). The integrity of the files to be appended is
115 verified using checksums which are stored in the checkpoint file. This ensures
116 that output can not be mixed up or corrupted due to file appending. When only
117 some of the previous output files are present, a fatal error is generated and
118 no old output files are modified and no new output files are opened. The
119 result with appending will be the same as from a single run. The contents will
120 be binary identical, unless you use a different number of ranks or dynamic
121 load balancing or the FFT library uses optimizations through timing.
123 With option -maxh a simulation is terminated and a checkpoint file is written
124 at the first neighbor search step where the run time exceeds -maxh*0.99 hours.
125 This option is particularly useful in combination with setting nsteps to -1
126 either in the mdp or using the similarly named command line option (although
127 the latter is deprecated). This results in an infinite run, terminated only
128 when the time limit set by -maxh is reached (if any) or upon receiving a
131 Interactive molecular dynamics (IMD) can be activated by using at least one of
132 the three IMD switches: The -imdterm switch allows one to terminate the
133 simulation from the molecular viewer (e.g. VMD). With -imdwait, mdrun pauses
134 whenever no IMD client is connected. Pulling from the IMD remote can be turned
135 on by -imdpull. The port mdrun listens to can be altered by -imdport.The file
136 pointed to by -if contains atom indices and forces if IMD pulling is used.
140 Options to specify input files:
142 -s [<.tpr>] (topol.tpr)
143 Portable xdr run input file
144 -cpi [<.cpt>] (state.cpt) (Opt.)
146 -table [<.xvg>] (table.xvg) (Opt.)
148 -tablep [<.xvg>] (tablep.xvg) (Opt.)
150 -tableb [<.xvg> [...]] (table.xvg) (Opt.)
152 -rerun [<.xtc/.trr/...>] (rerun.xtc) (Opt.)
153 Trajectory: xtc trr cpt gro g96 pdb tng
154 -ei [<.edi>] (sam.edi) (Opt.)
156 -multidir [<dir> [...]] (rundir) (Opt.)
158 -awh [<.xvg>] (awhinit.xvg) (Opt.)
160 -membed [<.dat>] (membed.dat) (Opt.)
162 -mp [<.top>] (membed.top) (Opt.)
164 -mn [<.ndx>] (membed.ndx) (Opt.)
167 Options to specify output files:
169 -o [<.trr/.cpt/...>] (traj.trr)
170 Full precision trajectory: trr cpt tng
171 -x [<.xtc/.tng>] (traj_comp.xtc) (Opt.)
172 Compressed trajectory (tng format or portable xdr format)
173 -cpo [<.cpt>] (state.cpt) (Opt.)
175 -c [<.gro/.g96/...>] (confout.gro)
176 Structure file: gro g96 pdb brk ent esp
177 -e [<.edr>] (ener.edr)
179 -g [<.log>] (md.log)
181 -dhdl [<.xvg>] (dhdl.xvg) (Opt.)
183 -field [<.xvg>] (field.xvg) (Opt.)
185 -tpi [<.xvg>] (tpi.xvg) (Opt.)
187 -tpid [<.xvg>] (tpidist.xvg) (Opt.)
189 -eo [<.xvg>] (edsam.xvg) (Opt.)
191 -px [<.xvg>] (pullx.xvg) (Opt.)
193 -pf [<.xvg>] (pullf.xvg) (Opt.)
195 -ro [<.xvg>] (rotation.xvg) (Opt.)
197 -ra [<.log>] (rotangles.log) (Opt.)
199 -rs [<.log>] (rotslabs.log) (Opt.)
201 -rt [<.log>] (rottorque.log) (Opt.)
203 -mtx [<.mtx>] (nm.mtx) (Opt.)
205 -if [<.xvg>] (imdforces.xvg) (Opt.)
207 -swap [<.xvg>] (swapions.xvg) (Opt.)
212 -deffnm <string>
213 Set the default filename for all file options
214 -xvg <enum> (xmgrace)
215 xvg plot formatting: xmgrace, xmgr, none
216 -dd <vector> (0 0 0)
217 Domain decomposition grid, 0 is optimize
218 -ddorder <enum> (interleave)
219 DD rank order: interleave, pp_pme, cartesian
220 -npme <int> (-1)
221 Number of separate ranks to be used for PME, -1 is guess
223 Total number of threads to start (0 is guess)
224 -ntmpi <int> (0)
225 Number of thread-MPI ranks to start (0 is guess)
226 -ntomp <int> (0)
227 Number of OpenMP threads per MPI rank to start (0 is guess)
228 -ntomp_pme <int> (0)
229 Number of OpenMP threads per MPI rank to start (0 is -ntomp)
230 -pin <enum> (auto)
231 Whether mdrun should try to set thread affinities: auto, on, off
232 -pinoffset <int> (0)
233 The lowest logical core number to which mdrun should pin the first
235 -pinstride <int> (0)
236 Pinning distance in logical cores for threads, use 0 to minimize
237 the number of threads per physical core
238 -gpu_id <string>
239 List of unique GPU device IDs available to use
240 -gputasks <string>
241 List of GPU device IDs, mapping each PP task on each node to a
244 Check for all bonded interactions with DD
245 -rdd <real> (0)
246 The maximum distance for bonded interactions with DD (nm), 0 is
247 determine from initial coordinates
248 -rcon <real> (0)
249 Maximum distance for P-LINCS (nm), 0 is estimate
250 -dlb <enum> (auto)
251 Dynamic load balancing (with DD): auto, no, yes
252 -dds <real> (0.8)
253 Fraction in (0,1) by whose reciprocal the initial DD cell size will
254 be increased in order to provide a margin in which dynamic load
255 balancing can act while preserving the minimum cell size.
256 -nb <enum> (auto)
257 Calculate non-bonded interactions on: auto, cpu, gpu
258 -nstlist <int> (0)
259 Set nstlist when using a Verlet buffer tolerance (0 is guess)
261 Optimize PME load between PP/PME ranks or GPU/CPU (only with the
262 Verlet cut-off scheme)
263 -pme <enum> (auto)
264 Perform PME calculations on: auto, cpu, gpu
265 -pmefft <enum> (auto)
266 Perform PME FFT calculations on: auto, cpu, gpu
267 -bonded <enum> (auto)
268 Perform bonded calculations on: auto, cpu, gpu
271 -pforce <real> (-1)
272 Print all forces larger than this (kJ/mol nm)
274 Try to avoid optimizations that affect binary reproducibility
275 -cpt <real> (15)
276 Checkpoint interval (minutes)
278 Keep and number checkpoint files
280 Append to previous output files when continuing from checkpoint
281 instead of adding the simulation part number to all file names
282 -nsteps <int> (-2)
283 Run this number of steps (-1 means infinite, -2 means use mdp
284 option, smaller is invalid)
285 -maxh <real> (-1)
286 Terminate after 0.99 times this time (hours)
287 -replex <int> (0)
288 Attempt replica exchange periodically with this period (steps)
290 Number of random exchanges to carry out each exchange interval (N^3
291 is one suggestion). -nex zero or not specified gives neighbor
293 -reseed <int> (-1)
294 Seed for replica exchange, -1 is generate a seed