Don't forget to initialize cells[0]

src/cell_space.rs

@@ -55,9 +55,11 @@ where
         // result as this is the max number of elements per bucket.
         let max_offset = (distinct.len() / (1 << cell_bits)) + 1;
 
-        // Do not forget to initialise cells[0]
         let mut cells: Vec<Cell<V>> = Vec::with_capacity(1 << cell_bits);
 
+        // Do not forget to initialise cells[0]!
+        cells.push(Vec::with_capacity(max_offset));
+
         for coordinate in distinct {
             //trace!("{:?} {:?} {:?} {:?}", dimension, coordinate, cell, count);