ENH: Improve multi-variable drag compatibility, regular-grid handling, and related tests/docs

.pylintrc

@@ -99,10 +99,6 @@ recursive=no
 # source root.
 source-roots=
 
-# When enabled, pylint would attempt to guess common misconfiguration and emit
-# user-friendly hints instead of false-positive error messages.
-suggestion-mode=yes
-
 # Allow loading of arbitrary C extensions. Extensions are imported into the
 # active Python interpreter and may run arbitrary code.
 unsafe-load-any-extension=no

docs/user/function.rst

@@ -90,9 +90,13 @@ plotted as follows:
 
 .. important::
 
-    The ``Function`` class only supports interpolation ``shepard`` and \
-    extrapolation ``natural`` for datasets higher than one dimension (more than \
-    one input). 
+    For datasets higher than one dimension (more than one input), the
+    ``Function`` class supports interpolation ``linear``, ``shepard``, ``rbf``
+    and ``regular_grid``.
+
+    The ``regular_grid`` interpolation requires a complete Cartesian grid and
+    must be provided as ``(axes, grid_data)``. See the ``Function`` API
+    documentation for details.
 
 CSV File
 ^^^^^^^^
@@ -183,7 +187,7 @@ In this section we are going to delve deeper on ``Function`` creation and its pa
 - source: the ``Function`` data source. We have explored this parameter in the section above;
 - inputs: a list of strings containing each input variable name. If the source only has one input, may be abbreviated as a string (e.g. "speed (m/s)");
 - outputs: a list of strings containing each output variable name. If the source only has one output, may be abbreviated as a string (e.g. "total energy (J)");
-- interpolation: a string that is the interpolation method to be used if the source is a dataset. Defaults to ``spline``;
+- interpolation: a string that is the interpolation method to be used if the source is a dataset. For N-D datasets, supported options are ``linear``, ``shepard``, ``rbf`` and ``regular_grid``. Defaults to ``spline`` for 1-D and ``shepard`` for N-D datasets;
 - extrapolation: a string that is the extrapolation method to be used if the source is a dataset. Defaults to ``constant``;
 - title: the title to be shown in the plots.
 

docs/user/rocket/generic_surface.rst

@@ -243,16 +243,17 @@ independent variables:
 - ``beta``: Side slip angle.
 - ``mach``: Mach number.
 - ``reynolds``: Reynolds number.
-- ``q``: Pitch rate.
-- ``r``: Yaw rate.
-- ``p``: Roll rate.
+- ``pitch_rate``: Pitch rate.
+- ``yaw_rate``: Yaw rate.
+- ``roll_rate``: Roll rate.
 
 The last column must be the coefficient value, and must contain a header, 
 though the header name can be anything.
 
 .. important::
    Not all columns need to be present in the file, but the columns that are
-   present must be named, **and ordered**, as described above.
+   present must be correctly named as described above. Independent variable
+   columns can be in any order.
 
 An example of a ``.csv`` file is shown below: