Add implementation note

README.md

@@ -8,6 +8,7 @@
 Fast evaluation of the real valued parts of the principal and secondary branches of the [Lambert W function](https://en.wikipedia.org/wiki/Lambert_W_function) using the [method of Toshio Fukushima](https://www.researchgate.net/publication/346309410_Precise_and_fast_computation_of_Lambert_W_function_by_piecewise_minimax_rational_function_approximation_with_variable_transformation) to either 24 or 50 bits of accuracy.
 
 This method uses a piecewise minimax rational function approximation with variable transformations.
+It is implemented in code as conditional switches on the input value followed by either a square root or a logarithm and finished by a series of cumulative multiplies by fixed constants.
 
 ## Examples
 

src/lib.rs

@@ -3,6 +3,7 @@
 //! Fast evaluation of the real valued parts of the principal and secondary branches of the [Lambert W function](https://en.wikipedia.org/wiki/Lambert_W_function) using the [method of Toshio Fukushima](https://www.researchgate.net/publication/346309410_Precise_and_fast_computation_of_Lambert_W_function_by_piecewise_minimax_rational_function_approximation_with_variable_transformation) to either 24 or 50 bits of accuracy.
 //!
 //! This method uses a piecewise minimax rational function approximation with variable transformations.
+//! It is implemented in code as conditional switches on the input value followed by either a square root or a logarithm and finished by a series of cumulative multiplies by fixed constants.
 //!
 //! ## Examples
 //!