diff --git a/rust/src/swing.rs b/rust/src/swing.rs
index 7db144c4..c8a112b2 100644
--- a/rust/src/swing.rs
+++ b/rust/src/swing.rs
@@ -11,13 +11,11 @@ use crate::sparse::{get_row, CsrMatrix};
 #[pyclass(module = "recfarm", name = "Swing")]
 #[derive(Serialize, Deserialize)]
 pub struct PySwing {
-    task: String,
     top_k: usize,
     alpha: f32,
     max_cache_num: usize,
     n_users: usize,
     n_items: usize,
-    cum_swings: FxHashMap<i32, f32>,
     swing_score_mapping: FxHashMap<i32, Vec<(i32, f32)>>,
     user_interactions: CsrMatrix<i32, f32>,
     item_interactions: CsrMatrix<i32, f32>,
@@ -45,7 +43,6 @@ impl PySwing {
 
     #[new]
     fn new(
-        task: &str,
         top_k: usize,
         alpha: f32,
         max_cache_num: usize,
@@ -60,13 +57,11 @@ impl PySwing {
         let user_interactions: CsrMatrix<i32, f32> = user_interactions.extract()?;
         let item_interactions: CsrMatrix<i32, f32> = item_interactions.extract()?;
         Ok(Self {
-            task: task.to_owned(),
             top_k,
             alpha,
             max_cache_num,
             n_users,
             n_items,
-            cum_swings: FxHashMap::default(),
             swing_score_mapping: FxHashMap::default(),
             user_interactions,
             item_interactions,
@@ -130,7 +125,7 @@ impl PySwing {
                     if k_nb_swings.is_empty() {
                         self.default_pred
                     } else {
-                        compute_pred(&self.task, &k_nb_swings, &k_nb_labels)?
+                        compute_pred("ranking", &k_nb_swings, &k_nb_labels)?
                     }
                 }
                 _ => self.default_pred,
@@ -223,12 +218,11 @@ mod tests {
     }
 
     fn get_swing_model() -> Result<PySwing, Box<dyn std::error::Error>> {
-        let task = "ranking";
         let top_k = 10;
         let alpha = 1.0;
         let cache_common_num = 100;
         let n_users = 3;
-        let n_items = 4;
+        let n_items = 5;
         let default_pred = 0.0;
         let swing = Python::with_gil(|py| -> PyResult<PySwing> {
             // item_interactions:
@@ -263,7 +257,6 @@ mod tests {
             .into_py_dict(py)?;
 
             let mut swing = PySwing::new(
-                task,
                 top_k,
                 alpha,
                 cache_common_num,