Match IC settings for both models and update descriptions

doc/default_files/richards-parameters.xml

@@ -113,7 +113,9 @@ adding an empty line, make text **bold** or ``monospaced``.
 
   <category name="initial">
     <parameter name="type">
-      <definition> There are currently two possible initial conditions to choose from: A HDF datafile (``data``), or analytic equations (``analytic``).</definition>
+      <definition> The data type representing the initial condition. Either an
+        HDF datafile (``data``), or analytic equations (``analytic``).
+      </definition>
       <values> data, analytic </values>
       <suggestion> analytic </suggestion>
       <comment> Choose initial condition type: data, analytic </comment>
@@ -136,7 +138,8 @@ adding an empty line, make text **bold** or ``monospaced``.
 
     <parameter name="file">
       <definition> Path to the initial condition data file
-        (``data`` type only).
+        (``data`` type only). DORiE currently only supports H5 files with
+        file extension ``.h5``.
       </definition>
       <values> path </values>
     </parameter>

doc/default_files/transport-parameters.xml

@@ -113,7 +113,9 @@ adding an empty line, make text **bold** or ``monospaced``.
 
   <category name="initial">
     <parameter name="type">
-      <definition> There are currently two possible initial conditions to choose from: A HDF datafile (``data``), or analytic equations (``analytic``).</definition>
+      <definition> The data type representing the initial condition. Either an
+        HDF datafile (``data``), or analytic equations (``analytic``).
+      </definition>
       <values> data, analytic </values>
       <suggestion> analytic </suggestion>
       <comment> Choose initial condition type: data, analytic </comment>
@@ -134,18 +136,26 @@ adding an empty line, make text **bold** or ``monospaced``.
       <suggestion> 0 </suggestion>
     </parameter>
 
-    <parameter name="datafile">
-      <definition> Path to the initial condition data file.
-        (``data`` type only)
+    <parameter name="file">
+      <definition> Path to the initial condition data file
+        (``data`` type only). DORiE currently only supports H5 files with
+        file extension ``.h5``.
       </definition>
       <values> path </values>
     </parameter>
 
     <parameter name="dataset">
-      <definition> Dataset to use as initial condition. (``data`` type only)
+      <definition> Dataset to use as initial condition (``data`` type only).
       </definition>
       <values> string </values>
     </parameter>
+
+    <parameter name="interpolation">
+      <definition> Interpolation type used for the data (``data`` type only).
+      </definition>
+      <values> nearest </values>
+      <suggestion> nearest </suggestion>
+    </parameter>
   </category>
 
   <category name="time">