Use immutable references when possible

Author: mmghannam

src/branchrule.rs

@@ -225,11 +225,11 @@ mod tests {
 
             let vars = model.vars();
             model.add_cons_node(
-                child1,
-                cons().eq(0.0).coef(&vars[0], 1.).coef(&vars[1], -1.),
+                &child1,
+                &cons().eq(0.0).coef(&vars[0], 1.).coef(&vars[1], -1.),
             );
 
-            model.add_cons_node(child2, cons().eq(1.0).coef(&vars[0], 1.).coef(&vars[1], 1.));
+            model.add_cons_node(&child2, &cons().eq(1.0).coef(&vars[0], 1.).coef(&vars[1], 1.));
 
             // model.add_cons_node(child1, vec![&vars[0], &vars[1]], &[1., -1.], 0., 0., "eq");
             // model.add_cons_node(child2, vec![&vars[0], &vars[1]], &[1., 1.], 0., 1., "diff");

src/model.rs

@@ -501,7 +501,7 @@ impl Model<Solving> {
     /// # Panics
     ///
     /// This method panics if the constraint cannot be created in the current state.
-    pub fn add_cons_local(&mut self, cons_builder: ConsBuilder) -> Constraint {
+    pub fn add_cons_local(&mut self, cons_builder: &ConsBuilder) -> Constraint {
         let vars: Vec<&Variable> = cons_builder.coefs.iter().map(|(var, _)| *var).collect();
         let coefs: Vec<f64> = cons_builder.coefs.iter().map(|(_, coef)| *coef).collect();
 
@@ -537,7 +537,7 @@ impl Model<Solving> {
     /// # Panics
     ///
     /// This method panics if the constraint cannot be created in the current state.
-    pub fn add_cons_node(&mut self, node: Node, cons_builder: ConsBuilder) -> Constraint {
+    pub fn add_cons_node(&mut self, node: &Node, cons_builder: &ConsBuilder) -> Constraint {
         let vars: Vec<&Variable> = cons_builder.coefs.iter().map(|(var, _)| *var).collect();
         let coefs: Vec<f64> = cons_builder.coefs.iter().map(|(_, coef)| *coef).collect();
 

src/scip.rs

@@ -354,7 +354,7 @@ impl ScipPtr {
 
     pub(crate) fn create_cons(
         &self,
-        node: Option<Node>,
+        node: Option<&Node>,
         vars: Vec<&Variable>,
         coefs: &[f64],
         lhs: f64,

src/separator.rs

@@ -292,7 +292,7 @@ mod tests {
             }
             model.add_cut(row, true);
 
-            model.add_cons_local(cons().ge(7.0).coef(&(vars[0]), 2.).coef(&(vars[1]), 1.));
+            model.add_cons_local(&cons().ge(7.0).coef(&(vars[0]), 2.).coef(&(vars[1]), 1.));
 
             SeparationResult::Separated
         }