[eigen] extend support for 1x1xN filters (#62)

include/fcarouge/internal/kalman_eigen.hpp

@@ -79,6 +79,17 @@ struct transpose {
 
     return result_type{ value.transpose() };
   }
+
+  //! @brief Returns the transpose of `value`.
+  //!
+  //! @param value Value to compute the transpose of.
+  //!
+  //! @todo Can this be optimized?
+  [[nodiscard]] inline constexpr auto
+  operator()(const arithmetic auto &value) const
+  {
+    return value;
+  }
 };
 
 //! @brief Function object for performing Eigen matrix symmetrization.
@@ -97,6 +108,17 @@ struct symmetrize {
 
     return result_type{ (value + value.transpose()) / 2 };
   }
+
+  //! @brief Returns the symmetrized `value`.
+  //!
+  //! @param value Value to compute the symmetry of.
+  //!
+  //! @todo Can this be optimized?
+  [[nodiscard]] inline constexpr auto
+  operator()(const arithmetic auto &value) const
+  {
+    return value;
+  }
 };
 
 //! @brief Function object for performing Eigen matrix division.

include/fcarouge/kalman.hpp

@@ -859,8 +859,10 @@ class kalman<Type, State, Output, Input, Transpose, Symmetrize, Divide,
   //! @details Predicts and updates the estimates per prediction arguments,
   //! control input, and measurement output.
   //!
-  //! @param arguments Optional prediction parameters passed through for
-  //! computations of prediction matrices.
+  //! @param prediction_arguments Optional prediction parameters passed through
+  //! for computations of prediction matrices.
+  //! @param update_arguments Optional update parameters passed through for
+  //! computations of update matrices.
   //! @param input_u Optional control parameters. Types must be compatible with
   //! the `Input` types. The parameter pack types must always be explicitly
   //! defined per the