[Sparse] Add clear_triplets()

nalgebra-sparse/src/coo.rs

@@ -211,6 +211,16 @@ impl<T> CooMatrix<T> {
         self.values.push(v);
     }
 
+    /// Clear all triplets from the matrix.
+    pub fn clear_triplets(&mut self)
+    where
+        T: PartialEq,
+    {
+        self.col_indices.clear();
+        self.row_indices.clear();
+        self.values.clear();
+    }
+
     /// The number of rows in the matrix.
     #[inline]
     #[must_use]

nalgebra-sparse/tests/unit_tests/coo.rs

@@ -226,6 +226,29 @@ fn coo_push_valid_entries() {
     );
 }
 
+#[test]
+fn coo_clear_triplets_valid_entries() {
+    let mut coo = CooMatrix::new(3, 3);
+
+    coo.push(0, 0, 1);
+    coo.push(0, 0, 2);
+    coo.push(2, 2, 3);
+    assert_eq!(
+        coo.triplet_iter().collect::<Vec<_>>(),
+        vec![(0, 0, &1), (0, 0, &2), (2, 2, &3)]
+    );
+    coo.clear_triplets();
+    assert_eq!(coo.triplet_iter().collect::<Vec<_>>(), vec![]);
+    // making sure everyhting works after clearing
+    coo.push(0, 0, 1);
+    coo.push(0, 0, 2);
+    coo.push(2, 2, 3);
+    assert_eq!(
+        coo.triplet_iter().collect::<Vec<_>>(),
+        vec![(0, 0, &1), (0, 0, &2), (2, 2, &3)]
+    );
+}
+
 #[test]
 fn coo_push_out_of_bounds_entries() {
     {