Add DiagonalWalkera and fix 3D KD grid

src/system/sticker.rs

@@ -1,3 +1,4 @@
+use anyhow::anyhow;
 use rand::Rng;
 use crate::system::{GriddedPosition, Position, Storage};
 
@@ -8,7 +9,17 @@ pub trait Sticker<P: Position, S: Storage<P>> {
 pub struct SimpleSticking;
 
 pub struct ProbabilisticSticking {
-    pub stick_probability: f32
+    pub(crate) stick_probability: f32
+}
+
+impl ProbabilisticSticking {
+    pub fn new(stick_probability: f32) -> anyhow::Result<ProbabilisticSticking> {
+        return if 0f32 < stick_probability && stick_probability <= 1f32 {
+            Ok(ProbabilisticSticking { stick_probability })
+        } else {
+            Err(anyhow!("Sticking probability outside of (0, 1] range."))
+        }
+    }
 }
 
 impl<P: GriddedPosition, S: Storage<P>> Sticker<P, S> for SimpleSticking {