From 8f51332adfcd6a5745c846682995edb94d2a1219 Mon Sep 17 00:00:00 2001 From: sjplimp Date: Fri, 22 Nov 2013 17:34:49 +0000 Subject: [PATCH] git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@11045 f3b2605a-c512-4ea7-a41b-209d697bcdaa --- doc/Section_howto.html | 11 ++++---- doc/Section_howto.txt | 11 ++++---- doc/Section_start.html | 18 ++++++++++++- doc/Section_start.txt | 18 ++++++++++++- doc/Section_tools.html | 22 +++++++++++----- doc/Section_tools.txt | 22 +++++++++++----- doc/read_dump.html | 6 ++--- doc/read_dump.txt | 6 ++--- doc/read_restart.html | 26 +++++++++--------- doc/read_restart.txt | 26 +++++++++--------- doc/restart.html | 60 +++++++++++++++++++++++++++++++++--------- doc/restart.txt | 55 ++++++++++++++++++++++++++++---------- doc/write_data.html | 5 +--- doc/write_data.txt | 5 +--- doc/write_restart.html | 54 +++++++++++++++++++++++++++++-------- doc/write_restart.txt | 52 +++++++++++++++++++++++++++--------- 16 files changed, 281 insertions(+), 116 deletions(-) diff --git a/doc/Section_howto.html b/doc/Section_howto.html index 74f4917096..69c8add025 100644 --- a/doc/Section_howto.html +++ b/doc/Section_howto.html @@ -51,10 +51,9 @@ run will continue from where the previous run left off. Or binary restart files can be saved to disk using the restart command. At a later time, these binary files can be read via a read_restart command in a new script. Or they can -be converted to text data files and read by a -read_data command in a new script. This -section discusses the restart2data tool that is -used to perform the conversion. +be converted to text data files using the -r command-line +switch and read by a +read_data command in a new script.

Here we give examples of 2 scripts that read either a binary restart file or a converted data file and then issue a new run command to @@ -100,9 +99,9 @@ notice that the thermodynamic data match at step 50 (if you also put a uses random numbers in a way that does not allow for perfect restarts.

As an alternate approach, the restart file could be converted to a data -file using this tool: +file as follows:

-
restart2data tmp.restart.50 tmp.restart.data 
+
lmp_g++ -r tmp.restart.50 tmp.restart.data 
 

 
Then, this script could be used to re-run the last 50 steps:
 

diff --git a/doc/Section_howto.txt b/doc/Section_howto.txt
index 9d1ba9911b..b52d2244d3 100644
--- a/doc/Section_howto.txt
+++ b/doc/Section_howto.txt
@@ -47,10 +47,9 @@ run will continue from where the previous run left off.  Or binary
 restart files can be saved to disk using the "restart"_restart.html
 command.  At a later time, these binary files can be read via a
 "read_restart"_read_restart.html command in a new script.  Or they can
-be converted to text data files and read by a
-"read_data"_read_data.html command in a new script.  "This
-section"_Section_tools.html discusses the {restart2data} tool that is
-used to perform the conversion.
+be converted to text data files using the "-r command-line
+switch"_Section_start.html#start_7 and read by a
+"read_data"_read_data.html command in a new script.
 
 Here we give examples of 2 scripts that read either a binary restart
 file or a converted data file and then issue a new run command to
@@ -96,9 +95,9 @@ notice that the thermodynamic data match at step 50 (if you also put a
 uses random numbers in a way that does not allow for perfect restarts.
 
 As an alternate approach, the restart file could be converted to a data
-file using this tool:
+file as follows:
 
-restart2data tmp.restart.50 tmp.restart.data :pre
+lmp_g++ -r tmp.restart.50 tmp.restart.data :pre
 
 Then, this script could be used to re-run the last 50 steps:
 
diff --git a/doc/Section_start.html b/doc/Section_start.html
index 230c8644ed..887b950630 100644
--- a/doc/Section_start.html
+++ b/doc/Section_start.html
@@ -1018,7 +1018,8 @@ letter abbreviation can be used:
 
  • -p or -partition
 
  • -pl or -plog
 
  • -ps or -pscreen
-
  • -r or -reorder
+
  • -r or -restart
+
  • -ro or -reorder
 
  • -sc or -screen
 
  • -sf or -suffix
 
  • -v or -var 
@@ -1138,6 +1139,21 @@ sub-directory (-pscreen replica_files/screen).  If this option is not
 used the screen file for partition N is screen.N or whatever is
 specified by the -screen command-line option.
 
    
+
    -restart restartfile datafile 
+
    
+
    Convert the restart file into a data file and immediately exit.  This
+is the same operation as if the following 2-line input script were
+run:
+
    
+
    read_restart restartfile
+write_data datafile 
+
    
+
    Note that the specified restartfile and datafile can have wild-card
+characters ("*",%") as described by the
+read_restart and write_data
+commands.  But a filename such as file.* will need to be enclosed in
+quotes to avoid shell expansion of the "*" character.
+
    
 
    -reorder nth N
 -reorder custom filename 
 
    
diff --git a/doc/Section_start.txt b/doc/Section_start.txt
index f785d4d103..f3e1bc778d 100644
--- a/doc/Section_start.txt
+++ b/doc/Section_start.txt
@@ -1009,7 +1009,8 @@ letter abbreviation can be used:
 -p or -partition
 -pl or -plog
 -ps or -pscreen
--r or -reorder
+-r or -restart
+-ro or -reorder
 -sc or -screen
 -sf or -suffix
 -v or -var :ul
@@ -1129,6 +1130,21 @@ sub-directory (-pscreen replica_files/screen).  If this option is not
 used the screen file for partition N is screen.N or whatever is
 specified by the -screen command-line option.
 
+-restart restartfile datafile :pre 
+
+Convert the restart file into a data file and immediately exit.  This
+is the same operation as if the following 2-line input script were
+run:
+
+read_restart restartfile
+write_data datafile :pre
+
+Note that the specified restartfile and datafile can have wild-card
+characters ("*",%") as described by the
+"read_restart"_read_restart.html and "write_data"_write_data.html
+commands.  But a filename such as file.* will need to be enclosed in
+quotes to avoid shell expansion of the "*" character.
+
 -reorder nth N
 -reorder custom filename :pre
 
diff --git a/doc/Section_tools.html b/doc/Section_tools.html
index fbbf46d10a..5c72e09e76 100644
--- a/doc/Section_tools.html
+++ b/doc/Section_tools.html
@@ -417,12 +417,22 @@ the README.txt file for more info.
 
 
    restart2data tool 
 
    
-
    IMPORTANT NOTE: LAMMPS now has a write_data command,
-which can create a data file from within an input script.  This means
-a two line input script can read a restart file, and write it as a
-data file.  When the write_data command is fully functional, the
-restart2data tool will be obsolete, and will be retired from the
-distribution.
+
    IMPORTANT NOTE: This tool is now obsolete and is not included in the
+current LAMMPS distribution.  This is becaues there is now a
+write_data command, which can create a data file
+from within an input script.  Running LAMMPS with the "-r"
+command-line switch as follows:
+
    
+
    lmp_g++ -r restartfile datafile
+
    
+
    is the same as running a 2-line input script:
+
    
+
    read_restart restartfile
+write_data datafile
+
    
+
    which will produce the same data file that the restart2data tool used
+to create.  The following information is included in case you have an
+older version of LAMMPS which still includes the restart2data tool.
 
    
 
    The file restart2data.cpp converts a binary LAMMPS restart file into
 an ASCII data file.  The syntax for running the tool is
diff --git a/doc/Section_tools.txt b/doc/Section_tools.txt
index 0f794fab38..c2383a29e8 100644
--- a/doc/Section_tools.txt
+++ b/doc/Section_tools.txt
@@ -413,12 +413,22 @@ These tools were written by Aidan Thompson at Sandia.
 
 restart2data tool :h4,link(restart)
 
-IMPORTANT NOTE: LAMMPS now has a "write_data"_write_data.html command,
-which can create a data file from within an input script.  This means
-a two line input script can read a restart file, and write it as a
-data file.  When the write_data command is fully functional, the
-restart2data tool will be obsolete, and will be retired from the
-distribution.
+IMPORTANT NOTE: This tool is now obsolete and is not included in the
+current LAMMPS distribution.  This is becaues there is now a
+"write_data"_write_data.html command, which can create a data file
+from within an input script.  Running LAMMPS with the "-r"
+"command-line switch"_Section_start.html#start_7 as follows:
+
+lmp_g++ -r restartfile datafile
+
+is the same as running a 2-line input script:
+
+read_restart restartfile
+write_data datafile
+
+which will produce the same data file that the restart2data tool used
+to create.  The following information is included in case you have an
+older version of LAMMPS which still includes the restart2data tool.
 
 The file restart2data.cpp converts a binary LAMMPS restart file into
 an ASCII data file.  The syntax for running the tool is
diff --git a/doc/read_dump.html b/doc/read_dump.html
index 323defc696..be9f384ee6 100644
--- a/doc/read_dump.html
+++ b/doc/read_dump.html
@@ -71,9 +71,9 @@ coordinates, and optionally the atom velocities and image flags and
 the simluation box dimensions.  This is useful for restarting a run
 from a particular snapshot in a dump file.  See the
 read_restart and read_data
-commands and the restart2data tool for
-alternative methods to do this.  Also see the rerun
-command for a means of reading multiple snapshots from a dump file.
+commands for alternative methods to do this.  Also see the
+rerun command for a means of reading multiple snapshots
+from a dump file.
 
    
 
    Note that a simulation box must already be defined before using the
 read_dump command.  This can be done by the
diff --git a/doc/read_dump.txt b/doc/read_dump.txt
index a7cddc6dfd..4a8a4a16ca 100644
--- a/doc/read_dump.txt
+++ b/doc/read_dump.txt
@@ -61,9 +61,9 @@ coordinates, and optionally the atom velocities and image flags and
 the simluation box dimensions.  This is useful for restarting a run
 from a particular snapshot in a dump file.  See the
 "read_restart"_read_restart.html and "read_data"_read_data.html
-commands and the "restart2data"_Section_tools.html#restart tool for
-alternative methods to do this.  Also see the "rerun"_rerun.html
-command for a means of reading multiple snapshots from a dump file.
+commands for alternative methods to do this.  Also see the
+"rerun"_rerun.html command for a means of reading multiple snapshots
+from a dump file.
 
 Note that a simulation box must already be defined before using the
 read_dump command.  This can be done by the
diff --git a/doc/read_restart.html b/doc/read_restart.html
index 2c76ce6bf9..8b70735df2 100644
--- a/doc/read_restart.html
+++ b/doc/read_restart.html
@@ -61,9 +61,9 @@ produced the restart file, it could be a LAMMPS bug, so consider
 wrong.
 
    
 
    Because restart files are binary, they may not be portable to other
-machines.  They can be converted to ASCII data files using the
-restart2data tool in the tools
-sub-directory of the LAMMPS distribution.
+machines.  In this case, you can use the -r command-line
+switch to convert a restart file to a data
+file.
 
    
 
    Similar to how restart files are written (see the
 write_restart and restart
@@ -81,16 +81,16 @@ set of multiple files to exist.  The restart and
 write_restart commands explain how such sets are
 created.  Read_restart will first read a filename where "%" is
 replaced by "base".  This file tells LAMMPS how many processors
-created the set.  Read_restart then reads the additional files.  For
-example, if the restart file was specified as save.% when it was
-written, then read_restart reads the files save.base, save.0, save.1,
-... save.P-1, where P is the number of processors that created the
-restart file.  The processors in the current LAMMPS simulation share
-the work of reading these files; each reads a roughly equal subset of
-the files.  The number of processors which created the set can be
-different the number of processors in the current LAMMPS simulation.
-This can be a fast mode of input on parallel machines that support
-parallel I/O.
+created the set and how many files are in it.  Read_restart then reads
+the additional files.  For example, if the restart file was specified
+as save.% when it was written, then read_restart reads the files
+save.base, save.0, save.1, ... save.P-1, where P is the number of
+processors that created the restart file.  The processors in the
+current LAMMPS simulation share the work of reading these files; each
+reads a roughly equal subset of the files.  The number of processors
+which created the set can be different the number of processors in the
+current LAMMPS simulation.  This can be a fast mode of input on
+parallel machines that support parallel I/O.
 
    
 
    
 
diff --git a/doc/read_restart.txt b/doc/read_restart.txt
index cc7a95d656..dd0a293dab 100644
--- a/doc/read_restart.txt
+++ b/doc/read_restart.txt
@@ -58,9 +58,9 @@ produced the restart file, it could be a LAMMPS bug, so consider
 wrong.
 
 Because restart files are binary, they may not be portable to other
-machines.  They can be converted to ASCII data files using the
-"restart2data tool"_Section_tools.html#restart in the tools
-sub-directory of the LAMMPS distribution.
+machines.  In this case, you can use the "-r command-line
+switch"_Section_start.html#start_7 to convert a restart file to a data
+file.
 
 Similar to how restart files are written (see the
 "write_restart"_write_restart.html and "restart"_restart.html
@@ -78,16 +78,16 @@ set of multiple files to exist.  The "restart"_restart.html and
 "write_restart"_write_restart.html commands explain how such sets are
 created.  Read_restart will first read a filename where "%" is
 replaced by "base".  This file tells LAMMPS how many processors
-created the set.  Read_restart then reads the additional files.  For
-example, if the restart file was specified as save.% when it was
-written, then read_restart reads the files save.base, save.0, save.1,
-... save.P-1, where P is the number of processors that created the
-restart file.  The processors in the current LAMMPS simulation share
-the work of reading these files; each reads a roughly equal subset of
-the files.  The number of processors which created the set can be
-different the number of processors in the current LAMMPS simulation.
-This can be a fast mode of input on parallel machines that support
-parallel I/O.
+created the set and how many files are in it.  Read_restart then reads
+the additional files.  For example, if the restart file was specified
+as save.% when it was written, then read_restart reads the files
+save.base, save.0, save.1, ... save.P-1, where P is the number of
+processors that created the restart file.  The processors in the
+current LAMMPS simulation share the work of reading these files; each
+reads a roughly equal subset of the files.  The number of processors
+which created the set can be different the number of processors in the
+current LAMMPS simulation.  This can be a fast mode of input on
+parallel machines that support parallel I/O.
 
 :line
 
diff --git a/doc/restart.html b/doc/restart.html
index 2b651482a5..7091c9f3cc 100644
--- a/doc/restart.html
+++ b/doc/restart.html
@@ -14,13 +14,27 @@
 
    Syntax:
 
    
 
    restart 0
-restart N root
-restart N file1 file2 
+restart N root keyword value ...
+restart N file1 file2 keyword value ... 
 
    
-
    • N = write a restart file every this many timesteps
-
    • N can be a variable (see below)
-
    • root = filename to which timestep # is appended
+
      • 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 
+
+
      • zero or more keyword/value pairs may be appended 
+
+
      • keyword = fileper or nfile 
+
+
          fileper arg = Np
+    Np = write one file for every this many processors
+  nfile arg = Nf
+    Nf = write this many files, one from each of Nf processors 
+
        
+
 
      
 
      Examples:
 
      
@@ -67,7 +81,8 @@ For example, the files written on step 1000 for filename restart.%
 would be restart.base.1000, restart.0.1000, restart.1.1000, ...,
 restart.P-1.1000.  This creates smaller files and can be a fast mode
 of output and subsequent input on parallel machines that support
-parallel I/O.
+parallel I/O.  The optional fileper and nfile keywords discussed
+below can alter the number of files written.
 
      
 
      Restart files are written on timesteps that are a multiple of N but
 not on the first timestep of a run or minimization.  You can use the
@@ -99,18 +114,37 @@ restart		v_s tmp.restart
 
      
 
 
      See the read_restart command for information about
-what is stored in a restart file.
+what is stored in a restart file.  
 
      
 
      Restart files can be read by a read_restart
 command to restart a simulation from a particular state.  Because the
 file is binary (to enable exact restarts), it may not be readable on
-another machine.  In this case, the restart2data
-program in the tools directory can be used
-to convert a restart file to an ASCII data file.  Both the
-read_restart command and restart2data tool can read in a restart file
-that was written with the "%" character so that multiple files were
-created.
+another machine.  In this case, you can use the -r command-line
+switch to convert a restart file to a data
+file.
 
      
+
      
+
+
      The optional nfile or fileper keywords can be used in conjunction
+with the "%" wildcard character in the specified restart file name(s).
+As explained above, the "%" character causes the restart file to be
+written in pieces, one piece for each of P processors.  By default P =
+the number of processors the simulation is running on.  The nfile or
+fileper keyword can be used to set P to a smaller value, which can
+be more efficient when running on a large number of processors.
+
      
+
      The nfile keyword sets P to the specified Nf value.  For example, if
+Nf = 4, and the simulation is running on 100 processors, 4 files will
+be written, by processors 0,25,50,75.  Each will collect information
+from itself and the next 24 processors and write it to a restart file.
+
      
+
      For the fileper keyword, the specified value of Np means write one
+file for every Np processors.  For example, if Np = 4, every 4th
+processor (0,4,8,12,etc) will collect information from itself and the
+next 3 processors and write it to a restart file.
+
      
+
      
+
 
      Restrictions: none
 
      
 
      Related commands:
diff --git a/doc/restart.txt b/doc/restart.txt
index 64caa28850..46104b8999 100644
--- a/doc/restart.txt
+++ b/doc/restart.txt
@@ -11,13 +11,20 @@ restart command :h3
 [Syntax:]
 
 restart 0
-restart N root
-restart N file1 file2 :pre
+restart N root keyword value ...
+restart N file1 file2 keyword value ... :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
+N = write a restart file every this many timesteps :ulb,l
+N can be a variable (see below) :l
+root = filename to which timestep # is appended :l
+file1,file2 = two full filenames, toggle between them when writing file :l
+zero or more keyword/value pairs may be appended :l
+keyword = {fileper} or {nfile} :l
+  {fileper} arg = Np
+    Np = write one file for every this many processors
+  {nfile} arg = Nf
+    Nf = write this many files, one from each of Nf processors :pre
+:ule
 
 [Examples:]
 
@@ -64,7 +71,8 @@ For example, the files written on step 1000 for filename restart.%
 would be restart.base.1000, restart.0.1000, restart.1.1000, ...,
 restart.P-1.1000.  This creates smaller files and can be a fast mode
 of output and subsequent input on parallel machines that support
-parallel I/O.
+parallel I/O.  The optional {fileper} and {nfile} keywords discussed
+below can alter the number of files written.
 
 Restart files are written on timesteps that are a multiple of N but
 not on the first timestep of a run or minimization.  You can use the
@@ -96,17 +104,36 @@ 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.
+what is stored in a restart file.  
 
 Restart files can be read by a "read_restart"_read_restart.html
 command to restart a simulation from a particular state.  Because the
 file is binary (to enable exact restarts), it may not be readable on
-another machine.  In this case, the "restart2data
-program"_Section_tools.html#restart in the tools directory can be used
-to convert a restart file to an ASCII data file.  Both the
-read_restart command and restart2data tool can read in a restart file
-that was written with the "%" character so that multiple files were
-created.
+another machine.  In this case, you can use the "-r command-line
+switch"_Section_start.html#start_7 to convert a restart file to a data
+file.
+
+:line
+
+The optional {nfile} or {fileper} keywords can be used in conjunction
+with the "%" wildcard character in the specified restart file name(s).
+As explained above, the "%" character causes the restart file to be
+written in pieces, one piece for each of P processors.  By default P =
+the number of processors the simulation is running on.  The {nfile} or
+{fileper} keyword can be used to set P to a smaller value, which can
+be more efficient when running on a large number of processors.
+
+The {nfile} keyword sets P to the specified Nf value.  For example, if
+Nf = 4, and the simulation is running on 100 processors, 4 files will
+be written, by processors 0,25,50,75.  Each will collect information
+from itself and the next 24 processors and write it to a restart file.
+
+For the {fileper} keyword, the specified value of Np means write one
+file for every Np processors.  For example, if Np = 4, every 4th
+processor (0,4,8,12,etc) will collect information from itself and the
+next 3 processors and write it to a restart file.
+
+:line
 
 [Restrictions:] none
 
diff --git a/doc/write_data.html b/doc/write_data.html
index c17f749e79..64ecc40b42 100644
--- a/doc/write_data.html
+++ b/doc/write_data.html
@@ -65,10 +65,7 @@ original input script.
 restart, write_restart, and
 read_restart commands.  You can also convert
 binary restart files to text data files, after a simulation has run,
-using the restart2data tool in the
-tools directory.  When the write_data command is fully implemented
-(see NOTE above), the restart2data command will be obsolete and will
-be removed from the LAMMPS distribution.
+using the -r command-line switch.
 
      
 
      IMPORTANT NOTE: Only limited information about a simulation is stored
 in a data file.  For example, no information about atom
diff --git a/doc/write_data.txt b/doc/write_data.txt
index bb5655476d..d914fe4b6c 100644
--- a/doc/write_data.txt
+++ b/doc/write_data.txt
@@ -58,10 +58,7 @@ If you want to do more exact restarts, using binary files, see the
 "restart"_restart.html, "write_restart"_write_restart.html, and
 "read_restart"_read_restart.html commands.  You can also convert
 binary restart files to text data files, after a simulation has run,
-using the "restart2data"_Section_tools.html#restart2data tool in the
-tools directory.  When the write_data command is fully implemented
-(see NOTE above), the restart2data command will be obsolete and will
-be removed from the LAMMPS distribution.
+using the "-r command-line switch"_Section_start.html#start_7.
 
 IMPORTANT NOTE: Only limited information about a simulation is stored
 in a data file.  For example, no information about atom
diff --git a/doc/write_restart.html b/doc/write_restart.html
index b3cfabddd6..16bd95cdf0 100644
--- a/doc/write_restart.html
+++ b/doc/write_restart.html
@@ -13,23 +13,34 @@
 
 
      Syntax:
 
      
-
      write_restart file 
+
      write_restart file keyword value ... 
 
      
 
      • file = name of file to write restart information to 
+
+
      • zero or more keyword/value pairs may be appended 
+
+
      • keyword = fileper or nfile 
+
+
          fileper arg = Np
+    Np = write one file for every this many processors
+  nfile arg = Nf
+    Nf = write this many files, one from each of Nf processors 
+
        
+
 
      
 
      Examples:
 
      
 
      write_restart restart.equil
-write_restart poly.%.* 
+write_restart poly.%.* nfile 10 
 
      
 
      Description:
 
      
 
      Write a binary restart file of the current state of the simulation.
 
      
 
      During a long simulation, the restart command is
-typically used to dump restart files periodically.  The write_restart
-command is useful after a minimization or whenever you wish to write
-out a single current restart file.
+typically used to output restart files periodically.  The
+write_restart command is useful after a minimization or whenever you
+wish to write out a single current restart file.
 
      
 
      Similar to dump files, the restart filename can contain
 two wild-card characters.  If a "*" appears in the filename, it is
@@ -41,16 +52,15 @@ contains global information.  For example, the files written for
 filename restart.% would be restart.base, restart.0, restart.1, ...
 restart.P-1.  This creates smaller files and can be a fast mode of
 output and subsequent input on parallel machines that support parallel
-I/O.
+I/O.  The optional fileper and nfile keywords discussed below can
+alter the number of files written.
 
      
 
      Restart files can be read by a read_restart
 command to restart a simulation from a particular state.  Because the
 file is binary (to enable exact restarts), it may not be readable on
-another machine.  In this case, the restart2data program in the tools
-directory can be used to convert a restart file to an ASCII data file.
-Both the read_restart command and restart2data tool can read in a
-restart file that was written with the "%" character so that multiple
-files were created.
+another machine.  In this case, you can use the -r command-line
+switch to convert a restart file to a data
+file.
 
      
 
      IMPORTANT NOTE: Although the purpose of restart files is to enable
 restarting a simulation from where it left off, not all information
@@ -63,6 +73,28 @@ in order to re-use that information.  See the
 read_restart command for information about what is
 stored in a restart file.
 
      
+
      
+
+
      The optional nfile or fileper keywords can be used in conjunction
+with the "%" wildcard character in the specified restart file name.
+As explained above, the "%" character causes the restart file to be
+written in pieces, one piece for each of P processors.  By default P =
+the number of processors the simulation is running on.  The nfile or
+fileper keyword can be used to set P to a smaller value, which can
+be more efficient when running on a large number of processors.
+
      
+
      The nfile keyword sets P to the specified Nf value.  For example, if
+Nf = 4, and the simulation is running on 100 processors, 4 files will
+be written, by processors 0,25,50,75.  Each will collect information
+from itself and the next 24 processors and write it to a restart file.
+
      
+
      For the fileper keyword, the specified value of Np means write one
+file for every Np processors.  For example, if Np = 4, every 4th
+processor (0,4,8,12,etc) will collect information from itself and the
+next 3 processors and write it to a restart file.
+
      
+
      
+
 
      Restrictions:
 
      
 
      This command requires inter-processor communication to migrate atoms
diff --git a/doc/write_restart.txt b/doc/write_restart.txt
index fcb99e4f39..8e3378681f 100644
--- a/doc/write_restart.txt
+++ b/doc/write_restart.txt
@@ -10,23 +10,30 @@ write_restart command :h3
 
 [Syntax:]
 
-write_restart file :pre
+write_restart file keyword value ... :pre
 
-file = name of file to write restart information to :ul
+file = name of file to write restart information to :ulb,l
+zero or more keyword/value pairs may be appended :l
+keyword = {fileper} or {nfile} :l
+  {fileper} arg = Np
+    Np = write one file for every this many processors
+  {nfile} arg = Nf
+    Nf = write this many files, one from each of Nf processors :pre
+:ule
 
 [Examples:]
 
 write_restart restart.equil
-write_restart poly.%.* :pre
+write_restart poly.%.* nfile 10 :pre
 
 [Description:]
 
 Write a binary restart file of the current state of the simulation.
 
 During a long simulation, the "restart"_restart.html command is
-typically used to dump restart files periodically.  The write_restart
-command is useful after a minimization or whenever you wish to write
-out a single current restart file.
+typically used to output restart files periodically.  The
+write_restart command is useful after a minimization or whenever you
+wish to write out a single current restart file.
 
 Similar to "dump"_dump.html files, the restart filename can contain
 two wild-card characters.  If a "*" appears in the filename, it is
@@ -38,16 +45,15 @@ contains global information.  For example, the files written for
 filename restart.% would be restart.base, restart.0, restart.1, ...
 restart.P-1.  This creates smaller files and can be a fast mode of
 output and subsequent input on parallel machines that support parallel
-I/O.
+I/O.  The optional {fileper} and {nfile} keywords discussed below can
+alter the number of files written.
 
 Restart files can be read by a "read_restart"_read_restart.html
 command to restart a simulation from a particular state.  Because the
 file is binary (to enable exact restarts), it may not be readable on
-another machine.  In this case, the restart2data program in the tools
-directory can be used to convert a restart file to an ASCII data file.
-Both the read_restart command and restart2data tool can read in a
-restart file that was written with the "%" character so that multiple
-files were created.
+another machine.  In this case, you can use the "-r command-line
+switch"_Section_start.html#start_7 to convert a restart file to a data
+file.
 
 IMPORTANT NOTE: Although the purpose of restart files is to enable
 restarting a simulation from where it left off, not all information
@@ -60,6 +66,28 @@ in order to re-use that information.  See the
 "read_restart"_read_restart.html command for information about what is
 stored in a restart file.
 
+:line
+
+The optional {nfile} or {fileper} keywords can be used in conjunction
+with the "%" wildcard character in the specified restart file name.
+As explained above, the "%" character causes the restart file to be
+written in pieces, one piece for each of P processors.  By default P =
+the number of processors the simulation is running on.  The {nfile} or
+{fileper} keyword can be used to set P to a smaller value, which can
+be more efficient when running on a large number of processors.
+
+The {nfile} keyword sets P to the specified Nf value.  For example, if
+Nf = 4, and the simulation is running on 100 processors, 4 files will
+be written, by processors 0,25,50,75.  Each will collect information
+from itself and the next 24 processors and write it to a restart file.
+
+For the {fileper} keyword, the specified value of Np means write one
+file for every Np processors.  For example, if Np = 4, every 4th
+processor (0,4,8,12,etc) will collect information from itself and the
+next 3 processors and write it to a restart file.
+
+:line
+
 [Restrictions:]
 
 This command requires inter-processor communication to migrate atoms