diff --git a/src/base/par_iter.rs b/src/base/par_iter.rs
index 8aaad348..93796b6a 100644
--- a/src/base/par_iter.rs
+++ b/src/base/par_iter.rs
@@ -6,7 +6,12 @@ use crate::{
 };
 use rayon::{iter::plumbing::bridge, prelude::*};
 
-/// A rayon parallel iterator over the colums of a matrix
+/// A rayon parallel iterator over the colums of a matrix. It is created
+/// using the [`par_column_iter`] method of [`Matrix`].
+///
+/// [`par_column_iter`]: crate::Matrix::par_column_iter
+/// [`Matrix`]: crate::Matrix
+#[cfg_attr(doc_cfg, doc(cfg(feature = "rayon")))]
 pub struct ParColumnIter<'a, T, R: Dim, Cols: Dim, S: RawStorage<T, R, Cols>> {
     mat: &'a Matrix<T, R, Cols, S>,
 }
@@ -18,6 +23,7 @@ impl<'a, T, R: Dim, Cols: Dim, S: RawStorage<T, R, Cols>> ParColumnIter<'a, T, R
     }
 }
 
+#[cfg_attr(doc_cfg, doc(cfg(feature = "rayon")))]
 impl<'a, T, R: Dim, Cols: Dim, S: RawStorage<T, R, Cols>> ParallelIterator
     for ParColumnIter<'a, T, R, Cols, S>
 where
@@ -38,6 +44,7 @@ where
     }
 }
 
+#[cfg_attr(doc_cfg, doc(cfg(feature = "rayon")))]
 impl<'a, T, R: Dim, Cols: Dim, S: RawStorage<T, R, Cols>> IndexedParallelIterator
     for ParColumnIter<'a, T, R, Cols, S>
 where
@@ -61,6 +68,7 @@ where
     }
 }
 
+#[cfg_attr(doc_cfg, doc(cfg(feature = "rayon")))]
 impl<T, R: Dim, Cols: Dim, S: RawStorage<T, R, Cols>> Matrix<T, R, Cols, S>
 where
     T: Send + Sync + Scalar,
@@ -72,6 +80,7 @@ where
     }
 }
 
+#[cfg_attr(doc_cfg, doc(cfg(feature = "rayon")))]
 /// A rayon parallel iterator through the mutable columns of a matrix
 pub struct ParColumnIterMut<
     'a,
@@ -83,6 +92,7 @@ pub struct ParColumnIterMut<
     mat: &'a mut Matrix<T, R, Cols, S>,
 }
 
+#[cfg_attr(doc_cfg, doc(cfg(feature = "rayon")))]
 impl<'a, T, R, Cols, S> ParColumnIterMut<'a, T, R, Cols, S>
 where
     R: Dim,
@@ -95,6 +105,7 @@ where
     }
 }
 
+#[cfg_attr(doc_cfg, doc(cfg(feature = "rayon")))]
 impl<'a, T, R, Cols, S> ParallelIterator for ParColumnIterMut<'a, T, R, Cols, S>
 where
     R: Dim,
@@ -116,6 +127,7 @@ where
     }
 }
 
+#[cfg_attr(doc_cfg, doc(cfg(feature = "rayon")))]
 impl<'a, T, R, Cols, S> IndexedParallelIterator for ParColumnIterMut<'a, T, R, Cols, S>
 where
     R: Dim,
@@ -141,6 +153,7 @@ where
     }
 }
 
+#[cfg_attr(doc_cfg, doc(cfg(feature = "rayon")))]
 impl<T, R: Dim, Cols: Dim, S: RawStorage<T, R, Cols> + RawStorageMut<T, R, Cols>>
     Matrix<T, R, Cols, S>
 where