starting point for cubic interpolation

Author: kylecarow

src/lib.rs

@@ -75,7 +75,7 @@
 //! and call `set_strategy`.
 //!
 //! ## Strategies
-//! An interpolation strategy (e.g. [`Linear`], [`Nearest`], [`LeftNearest`], [`RightNearest`]) must be specified.
+//! An interpolation strategy (e.g. [`Linear`], [`Cubic`], [`Nearest`], [`LeftNearest`], [`RightNearest`]) must be specified.
 //! Not all interpolation strategies are implemented for every dimensionality.
 //! [`Linear`] and [`Nearest`] are implemented for all dimensionalities.
 //!
@@ -117,7 +117,7 @@
 /// - The extrapolation setting enum: [`Extrapolate`]
 pub mod prelude {
     pub use crate::interpolator::*;
-    pub use crate::strategy::{LeftNearest, Linear, Nearest, RightNearest};
+    pub use crate::strategy::{Cubic, LeftNearest, Linear, Nearest, RightNearest};
     pub use crate::Extrapolate;
     pub use crate::Interpolator;
 }

src/strategy.rs

@@ -163,6 +163,14 @@ pub fn find_nearest_index<T: PartialOrd>(arr: ArrayView1<T>, target: T) -> usize
 #[derive(Debug)]
 pub struct Linear;
 
+// TODO: `pub struct Quadratic;`
+// Maybe `pub struct Polynomial(usize);` as well?
+// with `pub type Quadratic = Polynomial(2)` and `pub type Cubic = Polynomial(3)`
+
+/// Cubic spline interpolation: TODO
+#[derive(Debug)]
+pub struct Cubic;
+
 /// Nearest value interpolation: <https://en.wikipedia.org/wiki/Nearest-neighbor_interpolation>
 ///
 /// # Note