diff --git a/Cargo.toml b/Cargo.toml
index f0307df..6704f73 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,8 +16,13 @@ harness = false
 
 [dependencies]
 approx = { version = "0.5.1", optional = true }
+rayon = { version = "1", optional = true }
 smallvec = "1"
 
+[features]
+approx = ["dep:approx"]
+rayon = ["dep:rayon"]
+
 [dev-dependencies]
 criterion = "0.5"
 plotters = { version = "0.3", default-features = false, features = ["svg_backend", "all_elements", "all_series"] }