add RHEL info; note update to Py3.13

Author: briantoby

webdocs/install-g2f-linux.rst

@@ -32,7 +32,24 @@ The exact details for how the installation is performed will depend on "flavor"
    :alt: completion commands in terminal window 
    :align: right
 
-2) This will run for a few minutes (or longer depending on download speeds) and then the conda installation process will start, with the display of lots of text. At the end, the terminal window will appear as seen to the right. Note the addition of the GSASII file on the desktop (this may not happen on all Linux desktop managers.). The installation has been completed. 
+Note that binary compatibility between Linux systems is not all that
+good. The above is constructed on an Ubuntu 24.04.2 LTS GitHub runner, but
+that will not run on APS Redhat Enterprise Linux systems. For RHEL a
+separate installer is available. Use this command, instead::
+
+  g2="https://github.com/AdvancedPhotonSource/GSAS-II-buildtools/releases/download/v1.0.1/gsas2main-rhel-Latest-Linux-x86_64.sh"
+  curl -L "$g2" > /tmp/g2.sh; bash /tmp/g2.sh -b -p <install-loc>
+
+If neither of the two installers will work for your flavor of Linux
+(which will be obvious as starting either the GUI or loading the scriptable module
+will produce error messages about being unable to import the GSAS-II
+binaries), you will need to compile GSAS-II yourself. This can be done
+after using either of the two Linux installers by following the chapter
+`on compiling GSAS-II
+<https://advancedphotonsource.github.io/GSAS-II-tutorials/compile.html>`_. Note
+there the meson instructions.
+
+2) The previous install step will run for a few minutes (or longer depending on download speeds) and then the conda installation process will start, with the display of lots of text. At the end, the terminal window will appear as seen to the right. Note the addition of the GSASII file on the desktop (this may not happen on all Linux desktop managers.). The installation has been completed. 
 
 .. raw:: html
 

webdocs/install.rst

@@ -61,7 +61,16 @@ where:
 
  <install-loc> is where you want to install the software. (Use of ``~/g2main``, a subdirectory named ``g2main`` in your home directory is a good choice.) 
 
-More complete installation instructions are provided for `Linux separately <install-g2f-linux.html>`_.
+More complete installation instructions are provided for `Linux
+separately <install-g2f-linux.html>`_.
+
+Note that binary compatibility between Linux systems is not all that
+good. The above is constructed on an Ubuntu 24.04.2 LTS GitHub runner, but
+that will not run on APS Redhat Enterprise Linux systems. For RHEL a
+separate installer is available. Use this command, instead::
+
+  g2="https://github.com/AdvancedPhotonSource/GSAS-II-buildtools/releases/download/v1.0.1/gsas2main-rhel-Latest-Linux-x86_64.sh"
+  curl -L "$g2" > /tmp/g2.sh; bash /tmp/g2.sh -b -p <install-loc>
 
 
 GSAS2MAIN Additional Details
@@ -85,7 +94,7 @@ Users who work extensively with Python and use the conda Python installer may pr
 
   conda create -n GSASII briantoby::gsas2pkg  -c conda-forge
 
-This creates a conda virtual environment named ``GSASII`` (this can be changed) for use by GSAS-II. While it is also possible to install GSAS-II into the conda base environment, this is not recommended as it can create conflicts between Python and package versions needed by GSAS-II and those required by other packages. (If you choose to do this anyway, be sure to specify ``conda install python=3.11 briantoby::gsas2pkg`` as Python is likely to be pinned to a different version.)
+This creates a conda virtual environment named ``GSASII`` (this can be changed) for use by GSAS-II. While it is also possible to install GSAS-II into the conda base environment, this is not recommended as it can create conflicts between Python and package versions needed by GSAS-II and those required by other packages. (If you choose to do this anyway, be sure to specify ``conda install python=3.13 briantoby::gsas2pkg`` as Python is likely to be pinned to a different version.)
 
 After this command is run, use command ``conda activate GSASII`` to access the
 conda environment that has been created. On Linux and MacOS computers, two shortcut commands will then be available in the path, The first command, ``gsasII.sh``, which will start GSAS-II. This can optionally be used as ``gsasII.sh project.gpx`` to open existing project file ``project.gpx`` in GSAS-II. The second command, ``reset-gsasII.sh``  will rarely be used. This command will download the latest version of GSAS-II and update to that version, replacing any locally modified files with the original versions. This can be used to update GSAS-II when the program will not start, so the normal Help->Update menu command cannot be accessed. (Shortcuts available with gsas2pkg v5.1+.)
@@ -102,7 +111,8 @@ A small number of users or sites prefer to use Python distributions supplied via
 `found here <install-pip.html>`_. Independent of how Python is installed, multiple packages are needed, please see the
 `discussion on Python package requirements <https://gsas-ii.readthedocs.io/en/latest/packages.html#gui-requirements>`_, noting that the GSAS-II GUI requires at a minimum wxPython, matplotlib,
 PyOpenGL, NumPy and SciPy, while for scripting use, only NumPy and SciPy are required.  For full functionality, several other optional packages are needed.
-If versions other than those recommended are selected (Python=3.11 and NumPy=1.26), you will likely need to either locate older binaries and install them manually or compile them yourself (`see compilation information <https://advancedphotonsource.github.io/GSAS-II-tutorials/compile.html>`_). 
+If versions other than those recommended are selected (
+Python=3.13 with NumPy=2.2 or Python=3.11 with NumPy=1.26), you will likely need to either locate older binaries and install them manually or compile them yourself (`see compilation information <https://advancedphotonsource.github.io/GSAS-II-tutorials/compile.html>`_). 
 
 A simple way to install GSAS-II with a supplied Python environment uses the ``gitstrap.py`` script provided for this purpose. Use these commands (on any platform) to install GSAS-II::