By default (pre and post = yes), LAMMPS creates neighbor lists, computes forces, and imposes fix constraints before every run. And after every run it gathers and prints timings statistics. If a run is -just a continuation of a previous run (and no parameters have -changed), the initial computation is not necessary; the old neighbor -list is still valid as are the forces. So if pre is specified as -"no" then the initial setup is skipped, except for printing -thermodynamic info. Likewise, if post is specified as "no", the -full timing summary is skipped; only a one-line summary timing is -printed. Note that if pre is set to "no" for the 1st run LAMMPS -performs, then it is overridden, since the initial setup computations -must be done. +just a continuation of a previous run (i.e. no settings are changed), +the initial computation is not necessary; the old neighbor list is +still valid as are the forces. So if pre is specified as "no" then +the initial setup is skipped, except for printing thermodynamic info. +
+IMPORTANT NOTE: If your input script changes settings between 2 runs +(e.g. adds a fix or dump or +compute or changes a neighbor list +parameter), then the initial setup must be performed. LAMMPS does not +check for this, but it would be an error to use the pre option in +this case. +
+If post is specified as "no", the full timing summary is skipped; +only a one-line summary timing is printed. Note that if pre is set +to "no" for the 1st run LAMMPS performs, then it is overridden, since +the initial setup computations must be done.
The every option provides a means of interleaving LAMMPS runs with a command. This can be a short-hand abbreviation to avoid listing a diff --git a/doc/run.txt b/doc/run.txt index 13f6509616..11965eb2b4 100644 --- a/doc/run.txt +++ b/doc/run.txt @@ -90,15 +90,22 @@ other computations between successive short LAMMPS runs). By default (pre and post = yes), LAMMPS creates neighbor lists, computes forces, and imposes fix constraints before every run. And after every run it gathers and prints timings statistics. If a run is -just a continuation of a previous run (and no parameters have -changed), the initial computation is not necessary; the old neighbor -list is still valid as are the forces. So if {pre} is specified as -"no" then the initial setup is skipped, except for printing -thermodynamic info. Likewise, if {post} is specified as "no", the -full timing summary is skipped; only a one-line summary timing is -printed. Note that if {pre} is set to "no" for the 1st run LAMMPS -performs, then it is overridden, since the initial setup computations -must be done. +just a continuation of a previous run (i.e. no settings are changed), +the initial computation is not necessary; the old neighbor list is +still valid as are the forces. So if {pre} is specified as "no" then +the initial setup is skipped, except for printing thermodynamic info. + +IMPORTANT NOTE: If your input script changes settings between 2 runs +(e.g. adds a "fix"_fix.html or "dump"_dump.html or +"compute"_compute.html or changes a "neighbor"_neigh_modify.html list +parameter), then the initial setup must be performed. LAMMPS does not +check for this, but it would be an error to use the {pre} option in +this case. + +If {post} is specified as "no", the full timing summary is skipped; +only a one-line summary timing is printed. Note that if {pre} is set +to "no" for the 1st run LAMMPS performs, then it is overridden, since +the initial setup computations must be done. The {every} option provides a means of interleaving LAMMPS runs with a command. This can be a short-hand abbreviation to avoid listing a