removed unneeded notebooks, allowed openmc.Settings.max_order to take a None parameter, and revised notebooks according to comments from @paulromano, @wbinventor and @smharper.

docs/source/examples/index.rst

@@ -1,13 +1,13 @@
 .. _examples:
 
-=========================
-Example Jupyter Notebooks
-=========================
+=================
+Example Notebooks
+=================
 
-The following series of Jupyter Notebooks provide examples for usage of OpenMC
-features via the `Python API`_.
+The following series of Jupyter_ Notebooks provide examples for usage of OpenMC
+features via the :ref:`pythonapi`.
 
-.. _Python API: ../pythonapi/index.html
+.. _Jupyter: https://jupyter.org/
 
 .. toctree::
     :maxdepth: 1

docs/source/examples/mdgxs-part-i.rst

@@ -1,8 +1,8 @@
 .. _notebook_mdgxs_part_i:
 
-==========================
-MDGXS Part I: Introduction
-==========================
+===================================================================
+Multi-Group (Delayed) Cross Section Generation Part I: Introduction
+===================================================================
 
 .. only:: html
 

docs/source/examples/mdgxs-part-ii.rst

@@ -1,8 +1,8 @@
 .. _notebook_mdgxs_part_ii:
 
-================================
-MDGXS Part II: Advanced Features
-================================
+=========================================================================
+Multi-Group (Delayed) Cross Section Generation Part II: Advanced Features
+=========================================================================
 
 .. only:: html
 

docs/source/examples/mgxs-part-iv.rst

@@ -1,13 +0,0 @@
-.. _notebook_mgxs_part_iv:
-
-====================================================
-MGXS Part IV: Multi-Group Mode Cross-Section Library
-====================================================
-
-.. only:: html
-
-    .. notebook:: mgxs-part-iv.ipynb
-
-.. only:: latex
-
-    IPython notebooks must be viewed in the online HTML documentation.

docs/source/pythonapi/index.rst

@@ -6,12 +6,13 @@ Python API
 
 OpenMC includes a rich Python API that enables programmatic pre- and
 post-processing. The easiest way to begin using the API is to take a look at the
-example Jupyter_ notebooks provided. However, this assumes that you are already
-familiar with Python and common third-party packages such as NumPy_. If you have
-never programmed in Python before, there are many good tutorials available
-online. We recommend going through the modules from Codecademy_ and/or the
-`Scipy lectures`_. The full API documentation serves to provide more information
-on a given module or class.
+example Jupyter_ notebooks provided in the :ref:`examples` section of the
+documentation. However, this assumes that you are already familiar with Python
+and common third-party packages such as NumPy_. If you have never programmed in
+Python before, there are many good tutorials available online. We recommend
+going through the modules from Codecademy_ and/or the `Scipy lectures`_. The
+full API documentation serves to provide more information on a given module or
+class.
 
 ------------------------------------
 :mod:`openmc` -- Basic Functionality

openmc/settings.py

@@ -60,7 +60,7 @@ class Settings(object):
         type are 'variance', 'std_dev', and 'rel_err'. The threshold value
         should be a float indicating the variance, standard deviation, or
         relative error used.
-    max_order : int
+    max_order : None or int
         Maximum scattering order to apply globally when in multi-group mode.
     multipole_library : str
         Indicates the path to a directory containing a windowed multipole
@@ -456,8 +456,10 @@ class Settings(object):
 
     @max_order.setter
     def max_order(self, max_order):
-        cv.check_type('maximum scattering order', max_order, Integral)
-        cv.check_greater_than('maximum scattering order', max_order, 0, True)
+        if max_order is not None:
+            cv.check_type('maximum scattering order', max_order, Integral)
+            cv.check_greater_than('maximum scattering order', max_order, 0,
+                                  True)
         self._max_order = max_order
 
     @source.setter