Removed unnecessary dependency

Cargo.toml

@@ -7,7 +7,9 @@ battleship = []
 name = "bempp-octree"
 version = "0.0.1-dev"
 edition = "2021"
-authors = ["Srinath Kailasa <[email protected]>, Timo Betcke <[email protected]>"]
+authors = [
+    "Srinath Kailasa <[email protected]>, Timo Betcke <[email protected]>",
+]
 description = "A library to create Octrees"
 license = "BSD-3-Clause"
 homepage = "https://github.com/bempp/octree"
@@ -27,12 +29,11 @@ rand_chacha = "0.3.*"
 num = "0.4.*"
 bytemuck = "1.*"
 vtkio = "0.6.*"
-mpi = {version = "0.8.*", features = ["derive", "user-operations"] }
-once_cell = "*"
+mpi = { version = "0.8.*", features = ["derive", "user-operations"] }
 
 [profile.release]
 debug = 1
- 
+
 [dev-dependencies]
 rand_distr = "0.4.3"
 #criterion = { version = "0.5.*", features = ["html_reports"]}

examples/mpi_complete_tree.rs

@@ -56,7 +56,6 @@ pub fn main() {
     assert!(all_keys.contains_key(&MortonKey::root()));
 
     // Count the number of ghosts on each rank
-
     // Count the number of global keys on each rank.
 
     // Assert that all ghosts are from a different rank and count them.