Added wiener kernel

src/kernel.rs

@@ -1,14 +1,18 @@
 use ndarray::prelude::*;
 
+mod affine;
 mod constant;
 mod exponential;
 mod matern32;
 mod matern52;
+mod wiener;
 
+pub use affine::Affine;
 pub use constant::Constant;
 pub use exponential::Exponential;
 pub use matern32::Matern32;
 pub use matern52::Matern52;
+pub use wiener::Wiener;
 
 pub(crate) fn distance(ts1: &[f64], ts2: &[f64]) -> Array2<f64> {
     let mut r = Array2::zeros((ts1.len(), ts2.len()));
@@ -30,6 +34,7 @@ pub trait Kernel {
     fn state_cov(&self, t: f64) -> Array2<f64>;
     fn measurement_vector(&self) -> Array1<f64>;
     fn feedback(&self) -> Array2<f64>;
+    fn transition(&self, t0: f64, t1: f64) -> Array2<f64>;
 
     fn noise_effect(&self) -> Array2<f64> {
         unimplemented!();
@@ -39,10 +44,8 @@ pub trait Kernel {
         unimplemented!();
     }
 
-    fn transition(&self, t0: f64, t1: f64) -> Array2<f64>;
-
     fn noise_cov(&self, _t0: f64, _t1: f64) -> Array2<f64> {
-        todo!();
+        unimplemented!();
     }
 }