more edits to C library chapter

doc/src/Library_add.rst

@@ -2,11 +2,11 @@ Adding code to the Library interface
 ====================================
 
 The functionality of the LAMMPS library interface has historically
-always been motivated by the needs of its users and functions were
+been motivated by the needs of its users.  Functions have been added
-added or expanded as they were needed and used.  Contributions to
+or expanded as they were needed and used.  Contributions to the
-the interface are always welcome.  However with a refactoring of
+interface are always welcome.  However with a refactoring of the
-the library interface and its documentation that started in 2020,
+library interface and its documentation that started in 2020, there
-there are now a few requirements for inclusion of changes.
+are now a few requirements for including new changes or extensions.
 
   - New functions should be orthogonal to existing ones and not
     implement functionality that can already be achieved with the
@@ -17,17 +17,18 @@ there are now a few requirements for inclusion of changes.
     ``doc/src`` folder.
   - If possible, new unit tests to test those new features should
     be added.
-  - The new feature should also be implemented and documented for
+  - The new feature should also be implemented and documented not
-    the Python and Fortran modules.
+    just for the C interface, but also the Python and Fortran interfaces.
   - All additions should work and be compatible with ``-DLAMMPS_BIGBIG``,
-    ``-DLAMMPS_SMALLBIG``, ``-DLAMMPS_SMALLSMALL`` and compiling
+    ``-DLAMMPS_SMALLBIG``, ``-DLAMMPS_SMALLSMALL`` and when compiling
     with and without MPI support.
   - The ``library.h`` file should be kept compatible to C code at
     a level similar to C89. Its interfaces may not reference any
-    custom data types (e.g. ``bigint``, ``tagint``, and so on) only
+    custom data types (e.g. ``bigint``, ``tagint``, and so on) that
-    known inside of LAMMPS.
+    are only known inside of LAMMPS.
-  - only C style comments, not C++ style
+  - only use C style comments, not C++ style
+
+Please note that these are *not* *strict* requirements, but the LAMMPS
+developers appreciate if they are followed and can assist with
+implementing what is missing.
 
-Please note, that these are *not* *strict* requirements, but the
-LAMMPS developers appreciate if they are followed closely and will
-assist with implementing what is missing.

doc/src/Library_config.rst

@@ -18,18 +18,18 @@ This section documents the following functions:
 
 --------------------
 
-The following library functions can be used to query the LAMMPS library
+These library functions can be used to query the LAMMPS library for
-about compile time settings and included packages and styles.  This
+compile time settings and included packages and styles.  This enables
-enables programs that use the library interface to run LAMMPS
+programs that use the library interface to determine whether the
-simulations to determine, whether the linked LAMMPS library is compatible
+linked LAMMPS library is compatible with the requirements of the
-with the requirements of the application without crashing during the
+application without crashing during the LAMMPS functions (e.g. due to
-LAMMPS functions (e.g. due to missing pair styles from packages) or to
+missing pair styles from packages) or to choose between different
-choose between different options (e.g. whether to use ``lj/cut``,
+options (e.g. whether to use ``lj/cut``, ``lj/cut/opt``,
-``lj/cut/opt``, ``lj/cut/omp`` or ``lj/cut/intel``).  Most of the
+``lj/cut/omp`` or ``lj/cut/intel``).  Most of the functions can be
-functions can be called directly without first creating a LAMMPS
+called directly without first creating a LAMMPS instance.  While
-instance.  While crashes within LAMMPS may be recovered from through
+crashes within LAMMPS may be recovered from by enabling
-enabling :ref:`exceptions <exceptions>`, avoiding them proactively is
+:ref:`exceptions <exceptions>`, avoiding them proactively is a safer
-a safer approach.
+approach.
 
 .. code-block:: C
    :caption: Example for using configuration settings functions

doc/src/Library_neighbor.rst

@@ -1,8 +1,8 @@
 Accessing LAMMPS Neighbor lists
 ===============================
 
-The following functions allow to access neighbor lists
+The following functions enable access to neighbor lists generated by
-generated by LAMMPS or query their properties:
+LAMMPS or querying of their properties:
 
 - :cpp:func:`lammps_find_compute_neighlist`
 - :cpp:func:`lammps_find_fix_neighlist`

doc/src/Library_objects.rst

@@ -1,8 +1,8 @@
 Retrieving or setting properties of LAMMPS objects
 ==================================================
 
-This section documents accessing or modifying data from objects like
+This section documents accessing or modifying data stored by computes,
-computes, fixes, or variables in LAMMPS using following functions:
+fixes, or variables in LAMMPS using the following functions:
 
 - :cpp:func:`lammps_extract_compute`
 - :cpp:func:`lammps_extract_fix`

doc/src/Library_scatter.rst

@@ -1,7 +1,16 @@
 Library functions for scatter/gather operations
 ================================================
 
-This section documents the following functions:
+This section has functions which gather per-atom data from one or more
+processors into a contiguous global list ordered by atom ID.  The same
+list is returned to all calling processors.  It also contains
+functions which scatter per-atom data from a contiguous global list
+across the processors that own those atom IDs.  It also has a
+create_atoms() function which can create a new simulation by
+scattering atms appropriately to owning processors in the LAMMPS
+spatial decomposition.
+
+It documents the following functions:
 
 - :cpp:func:`lammps_gather_atoms`
 - :cpp:func:`lammps_gather_atoms_concat`
@@ -14,8 +23,6 @@ This section documents the following functions:
 - :cpp:func:`lammps_scatter`
 - :cpp:func:`lammps_scatter_subset`
 
-.. TODO add description
-
 -----------------------
 
 .. doxygenfunction:: lammps_gather_atoms

doc/src/Library_utility.rst

@@ -1,8 +1,8 @@
 Library interface utility functions
 ===================================
 
-To simplify some of the tasks, the library interface contains
+To simplify some tasks, the library interface contains these utility
-some utility functions that are not directly calling LAMMPS:
+functions.  They do not directly call the LAMMPS library.
 
 - :cpp:func:`lammps_encode_image_flags`
 - :cpp:func:`lammps_decode_image_flags`