Add links to amrex documentation (#1682)

Author: marchdf

docs/sphinx/user/inputs.rst

@@ -14,15 +14,21 @@ executable.
    $ ./amr_wind inputs.abl time.max_step=20
 
 
-The input file is a simple text file containing ``key = value`` entries for the
-input parameters. The text file can include comments, any text beginning with
-``#`` till the end of line (EOF) is interpreted as comments and ignored by the
-parser. Input file processing is handled by `AMReX ParmParse library
+The input file is a simple text file containing ``key = value``
+entries for the input parameters. The text file can include comments,
+any text beginning with ``#`` till the end of line (EOF) is
+interpreted as comments and ignored by the parser. Input file
+processing is handled by `AMReX ParmParse library
 <https://amrex-codes.github.io/amrex/docs_html/Basics.html#parmparse>`_. This
-section documents the various input file parameters and their default values (if
-available). In :program:`amr_wind`, the input file is broken into *sections*
-indicated by a namespace prefix. For example, all inputs related to the problem
-domain are prefixed with ``geometry.`` and so on. A sample input file is shown below
+section documents the common input file parameters and their default
+values (if available). The focus is on AMR-Wind specific input options
+and some common AMReX options (these are fully documented in `AMReX
+<https://amrex-codes.github.io/amrex/docs_html/RuntimeParameters.html>`_).
+
+In :program:`amr_wind`, the input file
+is broken into *sections* indicated by a namespace prefix. For
+example, all inputs related to the problem domain are prefixed with
+``geometry.`` and so on. A sample input file is shown below
 
 .. literalinclude:: ./amr_wind_inputs.txt
    :linenos:

docs/sphinx/user/inputs_MLMG.rst

@@ -3,6 +3,15 @@
 Section: MLMG options
 ~~~~~~~~~~~~~~~~~~~~~
 
+.. tip::
+
+   For further information the user is directed to the `AMReX linear
+   solver documentation
+   <ttps://amrex-codes.github.io/amrex/docs_html/LinearSolvers_Chapter.html>`_
+   and other `AMReX runtime parameters
+   <https://amrex-codes.github.io/amrex/docs_html/RuntimeParameters.html>_`
+
+
 This section specifies the Multi-Level Multi-Grid (MLMG) options for each type
 of linear solve. There are three types of linear solves performed in AMR-Wind
 "diffusion" which is a cell based Helmholtz like solve to advance the momentum
@@ -13,6 +22,7 @@ described but the same options apply to "nodal_proj" and "mac_proj". It is also
 possible to specify diffusion solver options for specific equations such as
 temperature, to do that use "temperature_diffusion" as your prefix.
 
+
 **Linear operator options**
 
 .. input_param:: diffusion.max_coarsening_level

docs/sphinx/user/inputs_amr.rst

@@ -1,11 +1,21 @@
 .. _inputs_amr:
 
-Section: amr
-~~~~~~~~~~~~
+Section: AMReX and AMR
+~~~~~~~~~~~~~~~~~~~~~~
 
-This section contains input parameters used by the core AMReX mesh data
-structure ``AmrCore`` to determine the base mesh and adaptive mesh refinement
-strategies. The refinement criteria is specified through :ref:`inputs_tagging`
+.. tip::
+
+   The user is encouraged to refer to the full list of `AMReX runtime
+   parameters
+   <https://amrex-codes.github.io/amrex/docs_html/RuntimeParameters.html>_`
+   for more advanced usage. Another section of particular interest is
+   the `description of AMReX grid creation
+   <https://amrex-codes.github.io/amrex/docs_html/GridCreation.html#sec-grid-creation>_`.
+
+This section contains some of the common input parameters used by the
+core AMReX mesh data structure ``AmrCore`` to determine the base mesh
+and adaptive mesh refinement strategies. The refinement criteria is
+specified through :ref:`inputs_tagging`.
 
 .. input_param:: amr.n_cell
 
@@ -23,7 +33,7 @@ strategies. The refinement criteria is specified through :ref:`inputs_tagging`
 
 .. input_param:: amr.max_grid_size
 
-   **type:** Integer, optional, default: 32
+   **type:** Integer, optional, default: [build dependent]
 
    Maximum number of cells at level 0 in each grid.
    There are also options to specify this value in each direction,