diff --git a/src/params.rs b/src/params.rs
index cf89a53..8325ddc 100644
--- a/src/params.rs
+++ b/src/params.rs
@@ -86,7 +86,8 @@ impl Params {
 
     pub fn fit(&mut self, data: &Matrix) -> Result<Model, Error> {
         let prob = data.to_problem();
-        let model = unsafe { mf_train(&prob, self.build_param()?) };
+        let param = self.build_param()?;
+        let model = unsafe { mf_train(&prob, param) };
         if model.is_null() {
             return Err(Error("fit failed".to_string()));
         }
@@ -96,7 +97,8 @@ impl Params {
     pub fn fit_eval(&mut self, train_set: &Matrix, eval_set: &Matrix) -> Result<Model, Error> {
         let tr = train_set.to_problem();
         let va = eval_set.to_problem();
-        let model = unsafe { mf_train_with_validation(&tr, &va, self.build_param()?) };
+        let param = self.build_param()?;
+        let model = unsafe { mf_train_with_validation(&tr, &va, param) };
         if model.is_null() {
             return Err(Error("fit_eval failed".to_string()));
         }
@@ -105,7 +107,8 @@ impl Params {
 
     pub fn cv(&mut self, data: &Matrix, folds: i32) -> Result<f64, Error> {
         let prob = data.to_problem();
-        let avg_error = unsafe { mf_cross_validation(&prob, folds, self.build_param()?) };
+        let param = self.build_param()?;
+        let avg_error = unsafe { mf_cross_validation(&prob, folds, param) };
         // TODO update fork to differentiate between bad parameters and zero error
         if avg_error == 0.0 {
             return Err(Error("cv failed".to_string()));