update documentation for removal of MPIIO package

doc/src/Build_basics.rst

@@ -90,7 +90,7 @@ standard. A more detailed discussion of that is below.
       directory, or ``make`` from the ``src/STUBS`` dir.  If the build
       fails, you may need to edit the ``STUBS/Makefile`` for your
       platform.  The stubs library does not provide MPI/IO functions
-      required by some LAMMPS packages, e.g. ``MPIIO`` or ``LATBOLTZ``,
+      required by some LAMMPS packages, e.g. ``LATBOLTZ``,
       and thus is not compatible with those packages.
 
       .. note::
@@ -128,14 +128,13 @@ and adds vectorization support when compiled with compatible compilers,
 in particular the Intel compilers on top of OpenMP. Also, the ``KOKKOS``
 package can be compiled to include OpenMP threading.
 
-In addition, there are a few commands in LAMMPS that have native
+In addition, there are a few commands in LAMMPS that have native OpenMP
-OpenMP support included as well.  These are commands in the ``MPIIO``,
+support included as well.  These are commands in the ``ML-SNAP``,
-``ML-SNAP``, ``DIFFRACTION``, and ``DPD-REACT`` packages.
+``DIFFRACTION``, and ``DPD-REACT`` packages.  Furthermore, some packages
-Furthermore, some packages support OpenMP threading indirectly through
+support OpenMP threading indirectly through the libraries they interface
-the libraries they interface to: e.g. ``KSPACE``, and ``COLVARS``.
+to: e.g. ``KSPACE``, and ``COLVARS``.  See the :doc:`Packages details
-See the :doc:`Packages details <Packages_details>` page for more info
+<Packages_details>` page for more info on these packages, and the pages
-on these packages, and the pages for their respective commands for
+for their respective commands for OpenMP threading info.
-OpenMP threading info.
 
 For CMake, if you use ``BUILD_OMP=yes``, you can use these packages
 and turn on their native OpenMP support and turn on their native OpenMP

doc/src/Commands_dump.rst

@@ -23,17 +23,14 @@ An alphabetic list of all LAMMPS :doc:`dump <dump>` commands.
    * :doc:`atom <dump>`
    * :doc:`atom/adios <dump_adios>`
    * :doc:`atom/gz <dump>`
-   * :doc:`atom/mpiio <dump>`
    * :doc:`atom/zstd <dump>`
    * :doc:`cfg <dump>`
    * :doc:`cfg/gz <dump>`
-   * :doc:`cfg/mpiio <dump>`
    * :doc:`cfg/uef <dump_cfg_uef>`
    * :doc:`cfg/zstd <dump>`
    * :doc:`custom <dump>`
    * :doc:`custom/adios <dump_adios>`
    * :doc:`custom/gz <dump>`
-   * :doc:`custom/mpiio <dump>`
    * :doc:`custom/zstd <dump>`
    * :doc:`dcd <dump>`
    * :doc:`grid <dump>`
@@ -51,7 +48,6 @@ An alphabetic list of all LAMMPS :doc:`dump <dump>` commands.
    * :doc:`xtc <dump>`
    * :doc:`xyz <dump>`
    * :doc:`xyz/gz <dump>`
-   * :doc:`xyz/mpiio <dump>`
    * :doc:`xyz/zstd <dump>`
    * :doc:`yaml <dump>`
 

doc/src/Commands_removed.rst

@@ -85,6 +85,25 @@ The same functionality is available through
 :doc:`bond style mesocnt <bond_mesocnt>` and
 :doc:`angle style mesocnt <angle_mesocnt>`.
 
+MPIIO package
+-------------
+
+.. deprecated:: TBD
+
+The MPIIO package has been removed from LAMMPS since it was unmaintained
+for many years and thus not updated to incorporate required changes that
+had been applied to the corresponding non-MPIIO commands. As a
+consequence the MPIIO commands had become unreliable and sometimes
+crashing LAMMPS or corrupting data.  Similar functionality is available
+through the :ref:`ADIOS package <PKG-ADIOS>` and the :ref:`NETCDF
+package <PKG-NETCDF>`.  Also, the :doc:`dump_modify nfile or dump_modify
+fileper <dump_modify>` keywords may be used for an efficient way of
+writing out dump files when running on large numbers of processors.
+Similarly, the "nfile" and "fileper" keywords exist for restarts:
+see :doc:`restart <restart>`, :doc:`read_restart <read_restart>`,
+:doc:`write_restart <write_restart>`.
+
+
 MSCG package
 ------------
 

doc/src/Errors_messages.rst

@@ -7148,9 +7148,6 @@ keyword to allow for additional bonds to be formed
 *Read_dump xyz fields do not have consistent scaling/wrapping*
    Self-explanatory.
 
-*Reading from MPI-IO filename when MPIIO package is not installed*
-   Self-explanatory.
-
 *Reax_defs.h setting for NATDEF is too small*
    Edit the setting in the ReaxFF library and re-compile the
    library and re-build LAMMPS.
@@ -8489,9 +8486,6 @@ keyword to allow for additional bonds to be formed
    The write_restart command cannot be used before a read_data,
    read_restart, or create_box command.
 
-*Writing to MPI-IO filename when MPIIO package is not installed*
-   Self-explanatory.
-
 *Zero length rotation vector with displace_atoms*
    Self-explanatory.
 

doc/src/Install_mac.rst

@@ -5,7 +5,7 @@ LAMMPS can be downloaded, built, and configured for macOS with `Homebrew
 <homebrew_>`_.  (Alternatively, see the installation instructions for
 :doc:`downloading an executable via Conda <Install_conda>`.)  The
 following LAMMPS packages are unavailable at this time because of
-additional requirements not yet met: GPU, KOKKOS, MSCG, MPIIO, POEMS,
+additional requirements not yet met: GPU, KOKKOS, MSCG, POEMS,
 VORONOI.
 
 After installing Homebrew, you can install LAMMPS on your system with

doc/src/Install_windows.rst

@@ -18,11 +18,10 @@ needed to run in parallel with MPI.
 
 The LAMMPS binaries contain *all* :doc:`optional packages <Packages>`
 included in the source distribution except: ADIOS, H5MD, KIM, ML-PACE,
-ML-QUIP, MSCG, NETCDF, PLUMED, QMMM, SCAFACOS, and VTK.  The serial
+ML-QUIP, MSCG, NETCDF, QMMM, SCAFACOS, and VTK.  The serial version also
-version also does not include the MPIIO and LATBOLTZ packages.  The
+does not include the LATBOLTZ package.  The PYTHON package is only
-PYTHON package is only available in the Python installers that bundle a
+available in the Python installers that bundle a Python runtime.  The
-Python runtime.  The GPU package is compiled for OpenCL with mixed
+GPU package is compiled for OpenCL with mixed precision kernels.
-precision kernels.
 
 The LAMMPS library is compiled as a shared library and the
 :doc:`LAMMPS Python module <Python_module>` is installed, so that

doc/src/Packages_details.rst

@@ -87,7 +87,6 @@ page gives those details.
    * :ref:`MOFFF <PKG-MOFFF>`
    * :ref:`MOLECULE <PKG-MOLECULE>`
    * :ref:`MOLFILE <PKG-MOLFILE>`
-   * :ref:`MPIIO <PKG-MPIIO>`
    * :ref:`NETCDF <PKG-NETCDF>`
    * :ref:`OPENMP <PKG-OPENMP>`
    * :ref:`OPT <PKG-OPT>`
@@ -2033,38 +2032,6 @@ This package has :ref:`specific installation instructions <molfile>` on the :doc
 
 ----------
 
-.. _PKG-MPIIO:
-
-MPIIO package
--------------
-
-**Contents:**
-
-Support for parallel output/input of dump and restart files via the
-MPIIO library.  It adds :doc:`dump styles <dump>` with a "mpiio" in
-their style name.  Restart files with an ".mpiio" suffix are also
-written and read in parallel.
-
-.. warning::
-
-   The MPIIO package is currently unmaintained and has become
-   unreliable. Use with caution.
-
-
-**Install:**
-
-The MPIIO package requires that LAMMPS is build in :ref:`MPI parallel mode <serial>`.
-
-**Supporting info:**
-
-* src/MPIIO: filenames -> commands
-* :doc:`dump <dump>`
-* :doc:`restart <restart>`
-* :doc:`write_restart <write_restart>`
-* :doc:`read_restart <read_restart>`
-
-----------
-
 .. _PKG-NETCDF:
 
 NETCDF package

doc/src/Packages_list.rst

@@ -333,11 +333,6 @@ whether an extra library is needed to build and use the package:
      - :doc:`dump molfile <dump_molfile>`
      - n/a
      - ext
-   * - :ref:`MPIIO <PKG-MPIIO>`
-     - MPI parallel I/O dump and restart
-     - :doc:`dump <dump>`
-     - n/a
-     - no
    * - :ref:`NETCDF <PKG-NETCDF>`
      - dump output via NetCDF
      - :doc:`dump netcdf <dump_netcdf>`

doc/src/dump.rst

@@ -14,10 +14,6 @@
 .. index:: dump custom/gz
 .. index:: dump local/gz
 .. index:: dump xyz/gz
-.. index:: dump atom/mpiio
-.. index:: dump cfg/mpiio
-.. index:: dump custom/mpiio
-.. index:: dump xyz/mpiio
 .. index:: dump atom/zstd
 .. index:: dump cfg/zstd
 .. index:: dump custom/zstd
@@ -63,7 +59,7 @@ Syntax
 
 * ID = user-assigned name for the dump
 * group-ID = ID of the group of atoms to be dumped
-* style = *atom* or *atom/adios* or *atom/gz* or *atom/zstd* or *atom/mpiio* or *cfg* or *cfg/gz* or *cfg/zstd* or *cfg/mpiio* or *cfg/uef* or *custom* or *custom/gz* or *custom/zstd* or *custom/mpiio* or *custom/adios* or *dcd* or *grid* or *grid/vtk* or *h5md* or *image* or *local* or *local/gz* or *local/zstd* or *molfile* or *movie* or *netcdf* or *netcdf/mpiio* or *vtk* or *xtc* or *xyz* or *xyz/gz* or *xyz/zstd* or *xyz/mpiio* or *yaml*
+* style = *atom* or *atom/adios* or *atom/gz* or *atom/zstd* or *cfg* or *cfg/gz* or *cfg/zstd* or *cfg/uef* or *custom* or *custom/gz* or *custom/zstd* or *custom/adios* or *dcd* or *grid* or *grid/vtk* or *h5md* or *image* or *local* or *local/gz* or *local/zstd* or *molfile* or *movie* or *netcdf* or *netcdf/mpiio* or *vtk* or *xtc* or *xyz* or *xyz/gz* or *xyz/zstd* or *yaml*
 * N = dump on timesteps which are multiples of N
 * file = name of file to write dump info to
 * attribute1,attribute2,... = list of attributes for a particular style
@@ -74,13 +70,11 @@ Syntax
        *atom/adios* attributes = none,  discussed on :doc:`dump atom/adios <dump_adios>` page
        *atom/gz* attributes = none
        *atom/zstd* attributes = none
-       *atom/mpiio* attributes = none
        *cfg* attributes = same as *custom* attributes, see below
        *cfg/gz* attributes = same as *custom* attributes, see below
        *cfg/zstd* attributes = same as *custom* attributes, see below
-       *cfg/mpiio* attributes = same as *custom* attributes, see below
        *cfg/uef* attributes = same as *custom* attributes, discussed on :doc:`dump cfg/uef <dump_cfg_uef>` page
-       *custom*, *custom/gz*, *custom/zstd*, *custom/mpiio* attributes = see below
+       *custom*, *custom/gz*, *custom/zstd* attributes = see below
        *custom/adios* attributes = same as *custom* attributes, discussed on :doc:`dump custom/adios <dump_adios>` page
        *dcd* attributes = none
        *h5md* attributes = discussed on :doc:`dump h5md <dump_h5md>` page
@@ -97,10 +91,9 @@ Syntax
        *xyz* attributes = none
        *xyz/gz* attributes = none
        *xyz/zstd* attributes = none
-       *xyz/mpiio* attributes = none
        *yaml* attributes = same as *custom* attributes, see below
 
-* *custom* or *custom/gz* or *custom/zstd* or *custom/mpiio* or *cfg* or *cfg/gz* or *cfg/zstd* or *cfg/mpiio* or *cfg/uef* or *netcdf* or *netcdf/mpiio* or *yaml* attributes:
+* *custom* or *custom/gz* or *custom/zstd* or *cfg* or *cfg/gz* or *cfg/zstd* or *cfg/uef* or *netcdf* or *netcdf/mpiio* or *yaml* attributes:
 
   .. parsed-literal::
 
@@ -179,11 +172,9 @@ Examples
 .. code-block:: LAMMPS
 
    dump myDump all atom 100 dump.lammpstrj
-   dump myDump all atom/mpiio 100 dump.atom.mpiio
    dump myDump all atom/gz 100 dump.atom.gz
    dump myDump all atom/zstd 100 dump.atom.zst
    dump 2 subgroup atom 50 dump.run.bin
-   dump 2 subgroup atom/mpiio 50 dump.run.mpiio.bin
    dump 4a all custom 100 dump.myforce.* id type x y vx fx
    dump 4a all custom 100 dump.myvel.lammpsbin id type x y z vx vy vz
    dump 4b flow custom 100 dump.%.myforce id type c_myF[3] v_ke
@@ -622,27 +613,10 @@ when running on large numbers of processors.
 Note that using the "\*" and "%" characters together can produce a
 large number of small dump files!
 
-For styles that end with *mpiio* an ".mpiio" must appear somewhere in
+.. deprecated:: TBD
-the specified filename.  These styles write their dump file in
-parallel via the MPI-IO library, which is part of the MPI standard for
-versions 2.0 and above.  Note these styles are identical in command
-syntax to the corresponding styles without "mpiio".  Likewise, the
-dump files produced by these MPI-IO styles are identical in format to
-the files produced by their non-MPI-IO style counterparts.  This means
-you can write a dump file using MPI-IO and use the :doc:`read_dump
-<read_dump>` command or perform other post-processing, just as if the
-dump file was not written using MPI-IO.
 
-Because MPI-IO dump files are one large file which all processors
+The MPIIO package and the the corresponding "/mpiio" dump styles, except
-write to, you cannot use the "%" wildcard character described above in
+for the unrelated "netcdf/mpiio" style were removed from LAMMPS.
-the filename.  However you can use the ".bin" or ".lammpsbin" suffix
-described below.  Again, this file will be written in parallel and
-have the same binary format as if it were written without MPI-IO.
-
-.. warning::
-
-   The MPIIO package within LAMMPS is currently unmaintained and has
-   become unreliable. Use with caution.
 
 ----------
 
@@ -956,11 +930,6 @@ the COMPRESS package.  They are only enabled if LAMMPS was built with
 that package.  See the :doc:`Build package <Build_package>` page for
 more info.
 
-The *atom/mpiio*, *cfg/mpiio*, *custom/mpiio*, and *xyz/mpiio* styles
-are part of the MPIIO package.  They are only enabled if LAMMPS was
-built with that package.  See the :doc:`Build package <Build_package>`
-page for more info.
-
 The *xtc*, *dcd*, and *yaml* styles are part of the EXTRA-DUMP package.
 They are only enabled if LAMMPS was built with that package.  See the
 :doc:`Build package <Build_package>` page for more info.
@@ -971,6 +940,7 @@ Related commands
 :doc:`dump atom/adios <dump_adios>`, :doc:`dump custom/adios <dump_adios>`,
 :doc:`dump cfg/uef <dump_cfg_uef>`, :doc:`dump h5md <dump_h5md>`,
 :doc:`dump image <dump_image>`, :doc:`dump molfile <dump_molfile>`,
+:doc:`dump netcdf <dump_netcdf>`, :doc:`dump netcdf/mpiio <dump_netcdf>`,
 :doc:`dump_modify <dump_modify>`, :doc:`undump <undump>`,
 :doc:`write_dump <write_dump>`
 

doc/src/dump_modify.rst

@@ -124,17 +124,6 @@ Description
 Modify the parameters of a previously defined dump command.  Not all
 parameters are relevant to all dump styles.
 
-As explained on the :doc:`dump <dump>` doc page, the *atom/mpiio*,
-*custom/mpiio*, and *xyz/mpiio* dump styles are identical in command
-syntax and in the format of the dump files they create, to the
-corresponding styles without "mpiio", except the single dump file they
-produce is written in parallel via the MPI-IO library.  Thus if a
-dump_modify option below is valid for the *atom* style, it is also
-valid for the *atom/mpiio* style, and similarly for the other styles
-which allow for use of MPI-IO.
-
-----------
-
 Unless otherwise noted, the following keywords apply to all the
 various dump styles, including the :doc:`dump image <dump_image>` and
 :doc:`dump movie <dump_image>` styles.
@@ -181,19 +170,20 @@ extra buffering.
 .. versionadded:: 4May2022
 
 The *colname* keyword can be used to change the default header keyword
-for dump styles: *atom*, *custom*, *cfg*, and *local* and their compressed,
+for dump styles: *atom*, *custom*, *cfg*, and *local* and their
-ADIOS, and MPIIO variants.  The setting for *ID string* replaces the default
+compressed, ADIOS variants.  The setting for *ID string* replaces the
-text with the provided string.  *ID* can be a positive integer when it
+default text with the provided string.  *ID* can be a positive integer
-represents the column number counting from the left, a negative integer
+when it represents the column number counting from the left, a negative
-when it represents the column number from the right (i.e. -1 is the last
+integer when it represents the column number from the right (i.e. -1 is
-column/keyword), or a custom dump keyword (or compute, fix, property, or
+the last column/keyword), or a custom dump keyword (or compute, fix,
-variable reference) and then it replaces the string for that specific
+property, or variable reference) and then it replaces the string for
-keyword. For *atom* dump styles only the keywords "id", "type", "x",
+that specific keyword. For *atom* dump styles only the keywords "id",
-"y", "z", "ix", "iy", "iz" can be accessed via string regardless of
+"type", "x", "y", "z", "ix", "iy", "iz" can be accessed via string
-whether scaled or unwrapped coordinates were enabled or disabled, and
+regardless of whether scaled or unwrapped coordinates were enabled or
-it always assumes 8 columns for indexing regardless of whether image
+disabled, and it always assumes 8 columns for indexing regardless of
-flags are enabled or not.  For dump style *cfg* only changes to the
+whether image flags are enabled or not.  For dump style *cfg* only
-"auxiliary" keywords (6th or later keyword) will become visible.
+changes to the "auxiliary" keywords (6th or later keyword) will become
+visible.
 
 The *colname* keyword can be used multiple times. If multiple *colname*
 settings refer to the same keyword, the last setting has precedence.  A
@@ -417,10 +407,10 @@ performed with dump style *xtc*\ .
 
 ----------
 
-The *format* keyword can be used to change the default numeric format output
+The *format* keyword can be used to change the default numeric format
-by the text-based dump styles: *atom*, *local*, *custom*, *cfg*, and
+output by the text-based dump styles: *atom*, *local*, *custom*, *cfg*,
-*xyz* styles, and their MPIIO variants. Only the *line* or *none*
+and *xyz* styles. Only the *line* or *none* options can be used with the
-options can be used with the *atom* and *xyz* styles.
+*atom* and *xyz* styles.
 
 All the specified format strings are C-style formats, such as used by
 the C/C++ printf() command.  The *line* keyword takes a single

doc/src/read_restart.rst

@@ -19,7 +19,6 @@ Examples
 
    read_restart save.10000
    read_restart restart.*
-   read_restart restart.*.mpiio
 
 Description
 """""""""""
@@ -120,22 +119,6 @@ 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.
 
-A restart file can also be read in parallel as one large binary file
-via the MPI-IO library, assuming it was also written with MPI-IO.
-MPI-IO is part of the MPI standard for versions 2.0 and above.  Using
-MPI-IO requires two steps.  First, build LAMMPS with its MPIIO package
-installed, e.g.
-
-.. code-block:: bash
-
-   make yes-mpiio    # installs the MPIIO package
-   make mpi          # build LAMMPS for your platform
-
-Second, use a restart filename which contains ".mpiio".  Note that it
-does not have to end in ".mpiio", just contain those characters.
-Unlike MPI-IO dump files, a particular restart file must be both
-written and read using MPI-IO.
-
 ----------
 
 Here is the list of information included in a restart file, which
@@ -268,8 +251,7 @@ information about these bonds is written to the restart file.
 Restrictions
 """"""""""""
 
-To write and read restart files in parallel with MPI-IO, the MPIIO
+none
-package must be installed.
 
 Related commands
 """"""""""""""""

doc/src/restart.rst

@@ -33,7 +33,6 @@ Examples
 
    restart 0
    restart 1000 poly.restart
-   restart 1000 poly.restart.mpiio
    restart 1000 restart.*.equil
    restart 10000 poly.%.1 poly.%.2 nfile 10
    restart v_mystep poly.restart
@@ -81,21 +80,6 @@ of output and subsequent input on parallel machines that support
 parallel I/O.  The optional *fileper* and *nfile* keywords discussed
 below can alter the number of files written.
 
-The restart file can also be written in parallel as one large binary
-file via the MPI-IO library, which is part of the MPI standard for
-versions 2.0 and above.  Using MPI-IO requires two steps.  First,
-build LAMMPS with its MPIIO package installed, e.g.
-
-.. code-block:: bash
-
-   make yes-mpiio    # installs the MPIIO package
-   make mpi          # build LAMMPS for your platform
-
-Second, use a restart filename which contains ".mpiio".  Note that it
-does not have to end in ".mpiio", just contain those characters.
-Unlike MPI-IO dump files, a particular restart file must be both
-written and read using MPI-IO.
-
 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
 :doc:`write_restart <write_restart>` command to write a restart file
@@ -104,15 +88,17 @@ 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 specified as an :doc:`equal-style variable <variable>`, which should be specified as v_name, where
+Instead of a numeric value, N can be specified as an :doc:`equal-style
-name is the variable name.  In this case, the variable is evaluated at
+variable <variable>`, which should be specified as v_name, where name is
-the beginning of a run to determine the next timestep at which a
+the variable name.  In this case, the variable is evaluated at the
-restart file will be written out.  On that timestep, the variable will
+beginning of a run to determine the next timestep at which a restart
-be evaluated again to determine the next timestep, etc.  Thus the
+file will be written out.  On that timestep, the variable will be
-variable should return timestep values.  See the stagger() and
+evaluated again to determine the next timestep, etc.  Thus the variable
-logfreq() and stride() math functions for :doc:`equal-style variables <variable>`, as examples of useful functions to use in
+should return timestep values.  See the stagger() and logfreq() and
-this context.  Other similar math functions could easily be added as
+stride() math functions for :doc:`equal-style variables <variable>`, as
-options for :doc:`equal-style variables <variable>`.
+examples of useful functions to use in this context.  Other similar math
+functions could easily be added as options for :doc:`equal-style
+variables <variable>`.
 
 For example, the following commands will write restart files
 every step from 1100 to 1200, and could be useful for debugging
@@ -170,8 +156,7 @@ next 3 processors and write it to a restart file.
 Restrictions
 """"""""""""
 
-To write and read restart files in parallel with MPI-IO, the MPIIO
+none
-package must be installed.
 
 Related commands
 """"""""""""""""

doc/src/write_restart.rst

@@ -27,7 +27,6 @@ Examples
 .. code-block:: LAMMPS
 
    write_restart restart.equil
-   write_restart restart.equil.mpiio
    write_restart poly.%.* nfile 10
 
 Description
@@ -53,32 +52,6 @@ output and subsequent input on parallel machines that support parallel
 I/O.  The optional *fileper* and *nfile* keywords discussed below can
 alter the number of files written.
 
-The restart file can also be written in parallel as one large binary
-file via the MPI-IO library, which is part of the MPI standard for
-versions 2.0 and above.  Using MPI-IO requires two steps.  First,
-build LAMMPS with its MPIIO package installed, e.g.
-
-.. tabs::
-
-   .. tab:: CMake build
-
-      .. code-block:: bash
-
-         cmake . -DPKG_MPIIO=on  # enables the MPIIO package in the build folder
-         cmake --build .         # recompiles LAMMPS with the package code included
-
-   .. tab:: Traditional make
-
-      .. code-block:: bash
-
-         make yes-mpiio    # installs the MPIIO package
-         make mpi          # build LAMMPS for your platform
-
-Second, use a restart filename which contains ".mpiio".  Note that it
-does not have to end in ".mpiio", just contain those characters.
-Unlike MPI-IO dump files, a particular restart file must be both
-written and read using MPI-IO.
-
 Restart files can be read by a :doc:`read_restart <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
@@ -128,9 +101,6 @@ before the restart file is written.  This means that your system must
 be ready to perform a simulation before using this command (force
 fields setup, atom masses initialized, etc).
 
-To write and read restart files in parallel with MPI-IO, the MPIIO
-package must be installed.
-
 Related commands
 """"""""""""""""