Fix example's BasicUnit array conversion.

A unit is a scalar, not a length-1 array. Though `BasicUnit` implements
`__rmul__`, if multiplying by an array, the NumPy implementation will
call `__array__` instead. If the LHS is an array, everything is fine,
but if the LHS is a scalar, the previous code would incorrectly cause it
to be upcast to a 1D array. When `__getitem__` was added in matplotlib#19415,
`np.atleast_1d` started iterating each (now 1D, not scalar)
`TaggedValue`, seeing it was length 1, and made the x/y arrays into
(N, 1) instead of (N,).

Author: QuLogic

examples/units/basic_units.py

@@ -218,7 +218,7 @@ def __array_wrap__(self, array, context):
         return TaggedValue(array, self)
 
     def __array__(self, t=None, context=None):
-        ret = np.array([1])
+        ret = np.array(1)
         if t is not None:
             return ret.astype(t)
         else: