Fix tri mask ops return docstring (#2517)

crates/burn-tensor/src/tensor/api/bool.rs

@@ -139,8 +139,22 @@ where
     ///
     /// # Returns
     ///
-    /// Returns a boolean tensor where `true` indicates the elements of the matrix that are part of the
-    /// upper triangle taking into account the specified `offset`.
+    /// Returns a boolean tensor where `false` indicates the elements of the matrix that are part of the
+    /// upper triangle taking into account the specified `offset`. All other elements are `true`.
+    ///
+    /// # Example
+    /// ```rust
+    /// use burn_tensor::backend::Backend;
+    /// use burn_tensor::{Tensor, Bool};
+    ///
+    /// fn example<B: Backend>() {
+    ///   let mask = Tensor::<B, 2, Bool>::triu_mask([3, 3], 0, &Default::default());
+    ///   println!("{mask}");
+    ///   // [[false, false, false],
+    ///   //  [true, false, false],
+    ///   //  [true, true, false]]
+    /// }
+    /// ```
     pub fn triu_mask<S: Into<Shape>>(shape: S, offset: i64, device: &B::Device) -> Self {
         Self::tri_mask(shape, TriPart::Upper, offset, device)
     }
@@ -159,8 +173,22 @@ where
     ///
     /// # Returns
     ///
-    /// Returns a boolean tensor where `true` indicates the elements of the matrix that are part of the
-    /// lower triangle taking into account the specified `offset`.
+    /// Returns a boolean tensor where `false` indicates the elements of the matrix that are part of the
+    /// lower triangle taking into account the specified `offset`. All other elements are `true`.
+    ///
+    /// # Example
+    /// ```rust
+    /// use burn_tensor::backend::Backend;
+    /// use burn_tensor::{Tensor, Bool};
+    ///
+    /// fn example<B: Backend>() {
+    ///   let mask = Tensor::<B, 2, Bool>::tril_mask([3, 3], 0, &Default::default());
+    ///   println!("{mask}");
+    ///   // [[false, true, true],
+    ///   //  [false, false, true],
+    ///   //  [false, false, false]]
+    /// }
+    /// ```
     pub fn tril_mask<S: Into<Shape>>(shape: S, offset: i64, device: &B::Device) -> Self {
         Self::tri_mask(shape, TriPart::Lower, offset, device)
     }
@@ -177,8 +205,22 @@ where
     ///
     /// # Returns
     ///
-    /// Returns a boolean tensor where `true` indicates the elements of the matrix that are part of the
-    /// diagonal.
+    /// Returns a boolean tensor where `false` indicates the elements of the matrix that are part of the
+    /// diagonal. All other elements are `true`.
+    ///
+    /// # Example
+    /// ```rust
+    /// use burn_tensor::backend::Backend;
+    /// use burn_tensor::{Tensor, Bool};
+    ///
+    /// fn example<B: Backend>() {
+    ///   let mask = Tensor::<B, 2, Bool>::diag_mask([3, 3], 0, &Default::default());
+    ///   println!("{mask}");
+    ///   // [[false, true, true],
+    ///   //  [true, false, true],
+    ///   //  [true, true, false]]
+    /// }
+    /// ```
     pub fn diag_mask<S: Into<Shape>>(shape: S, offset: i64, device: &B::Device) -> Self {
         Self::tri_mask(shape, TriPart::Diagonal, offset, device)
     }