restart 0 restart 1000 poly.restart restart 1000 restart.*.equil -restart 10000 poly.%.1 poly.%.2 +restart 10000 poly.%.1 poly.%.2 +restart v_mystep poly.restart
Description:
-Write out a binary restart file every so many timesteps as a run -proceeds. A value of 0 means do not write out restart files. Using -one filename as an argument will create a series of filenames which -include the timestep in the filename. Using two filenames will -produce only 2 restart files. LAMMPS will toggle between the 2 names -as it writes successive restart files. +
Write out a binary restart file every so many timesteps, in either or +both of two modes, as a run proceeds. A value of 0 means do not write +out any restart files. The two modes are as follows. If one filename +is specified, a series of filenames will be created which include the +timestep in the filename. If two filenames are specified, only 2 +restart files will be created, with those names. LAMMPS will toggle +between the 2 names as it writes successive restart files. +
+Note that you can specify the restart command twice, once with a +single filename and once with two filenames. This would allow you, +for example, to write out archival restart files every 100000 steps +using a single filenname, and more frequent temporary restart files +every 1000 steps, using two filenames. Using restart 0 will turn off +both modes of output.
Similar to dump files, the restart filename(s) can contain -two wild-card characters. If a "*" appears in the filename, it is -replaced with the current timestep value. This is only recognized -when a single filename is used (not when toggling back and forth). -Thus, the 3rd example above creates restart files as follows: -restart.1000.equil, restart.2000.equil, etc. If a single filename is -used with no "*", then the timestep value is appended. E.g. the 2nd -example above creates restart files as follows: poly.restart.1000, +two wild-card characters. +
+If a "*" appears in the single filename, it is replaced with the +current timestep value. This is only recognized when a single +filename is used (not when toggling back and forth). Thus, the 3rd +example above creates restart files as follows: restart.1000.equil, +restart.2000.equil, etc. If a single filename is used with no "*", +then the timestep value is appended. E.g. the 2nd example above +creates restart files as follows: poly.restart.1000, poly.restart.2000, etc.
If a "%" character appears in the restart filename(s), then one file @@ -58,11 +70,34 @@ of output and subsequent input on parallel machines that support parallel I/O.
Restart files are written on timesteps that are a multiple of N but -not on the first timestep of a run or minimization. A restart file is -not written on the last timestep of a run unless it is a multiple of -N. A restart file is written on the last timestep of a minimization -if N > 0 and the minimization converges. +not on the first timestep of a run or minimization. You can use the +write_restart command to write a restart file +before a run begins. A restart file is not written on the last +timestep of a run unless it is a multiple of N. A restart file is +written on the last timestep of a minimization if N > 0 and the +minimization converges.
+Instead of a numeric value, N can be specifed as an equal-style +variable, which should be specified as v_name, where +name is the variable name. In this case, the variable is evaluated at +the beginning of a run to determine the next timestep at which a +restart file will be written out. On that timestep, the variable will +be evaluated again to determine the next timestep, etc. Thus the +variable should return timestep values. See the stagger() and +logfreq() and stride() math functions for equal-style +variables, as examples of useful functions to use in +this context. Other similar math functions could easily be added as +options for equal-style variables. +
+For example, the following commands will write restart files +every step from 1100 to 1200, and could be useful for debugging +a simulation where something goes wrong at step 1163: +
+variable s equal stride(1100,1200,1) +restart v_s tmp.restart ++
See the read_restart command for information about what is stored in a restart file.
diff --git a/doc/restart.txt b/doc/restart.txt index 4e966bf269..64caa28850 100644 --- a/doc/restart.txt +++ b/doc/restart.txt @@ -15,6 +15,7 @@ restart N root restart N file1 file2 :pre N = write a restart file every this many timesteps +N can be a variable (see below) root = filename to which timestep # is appended file1,file2 = two full filenames, toggle between them when writing file :ul @@ -23,25 +24,36 @@ file1,file2 = two full filenames, toggle between them when writing file :ul restart 0 restart 1000 poly.restart restart 1000 restart.*.equil -restart 10000 poly.%.1 poly.%.2 :pre +restart 10000 poly.%.1 poly.%.2 +restart v_mystep poly.restart :pre [Description:] -Write out a binary restart file every so many timesteps as a run -proceeds. A value of 0 means do not write out restart files. Using -one filename as an argument will create a series of filenames which -include the timestep in the filename. Using two filenames will -produce only 2 restart files. LAMMPS will toggle between the 2 names -as it writes successive restart files. +Write out a binary restart file every so many timesteps, in either or +both of two modes, as a run proceeds. A value of 0 means do not write +out any restart files. The two modes are as follows. If one filename +is specified, a series of filenames will be created which include the +timestep in the filename. If two filenames are specified, only 2 +restart files will be created, with those names. LAMMPS will toggle +between the 2 names as it writes successive restart files. + +Note that you can specify the restart command twice, once with a +single filename and once with two filenames. This would allow you, +for example, to write out archival restart files every 100000 steps +using a single filenname, and more frequent temporary restart files +every 1000 steps, using two filenames. Using restart 0 will turn off +both modes of output. Similar to "dump"_dump.html files, the restart filename(s) can contain -two wild-card characters. If a "*" appears in the filename, it is -replaced with the current timestep value. This is only recognized -when a single filename is used (not when toggling back and forth). -Thus, the 3rd example above creates restart files as follows: -restart.1000.equil, restart.2000.equil, etc. If a single filename is -used with no "*", then the timestep value is appended. E.g. the 2nd -example above creates restart files as follows: poly.restart.1000, +two wild-card characters. + +If a "*" appears in the single filename, it is replaced with the +current timestep value. This is only recognized when a single +filename is used (not when toggling back and forth). Thus, the 3rd +example above creates restart files as follows: restart.1000.equil, +restart.2000.equil, etc. If a single filename is used with no "*", +then the timestep value is appended. E.g. the 2nd example above +creates restart files as follows: poly.restart.1000, poly.restart.2000, etc. If a "%" character appears in the restart filename(s), then one file @@ -55,10 +67,33 @@ of output and subsequent input on parallel machines that support parallel I/O. Restart files are written on timesteps that are a multiple of N but -not on the first timestep of a run or minimization. A restart file is -not written on the last timestep of a run unless it is a multiple of -N. A restart file is written on the last timestep of a minimization -if N > 0 and the minimization converges. +not on the first timestep of a run or minimization. You can use the +"write_restart"_write_restart.html command to write a restart file +before a run begins. A restart file is not written on the last +timestep of a run unless it is a multiple of N. A restart file is +written on the last timestep of a minimization if N > 0 and the +minimization converges. + +Instead of a numeric value, N can be specifed as an "equal-style +variable"_variable.html, which should be specified as v_name, where +name is the variable name. In this case, the variable is evaluated at +the beginning of a run to determine the next timestep at which a +restart file will be written out. On that timestep, the variable will +be evaluated again to determine the next timestep, etc. Thus the +variable should return timestep values. See the stagger() and +logfreq() and stride() math functions for "equal-style +variables"_variable.html, as examples of useful functions to use in +this context. Other similar math functions could easily be added as +options for "equal-style variables"_variable.html. + +For example, the following commands will write restart files +every step from 1100 to 1200, and could be useful for debugging +a simulation where something goes wrong at step 1163: + +variable s equal stride(1100,1200,1) +restart v_s tmp.restart :pre + +:line See the "read_restart"_read_restart.html command for information about what is stored in a restart file.