Remove use of Rc for Variable and Constraint & Add parameter getters

examples/create_and_solve.rs

@@ -13,20 +13,8 @@ fn main() {
     let x2 = model.add_var(0., f64::INFINITY, 4., "x2", VarType::Integer);
 
     // Add constraints
-    model.add_cons(
-        vec![x1.clone(), x2.clone()],
-        &[2., 1.],
-        -f64::INFINITY,
-        100.,
-        "c1",
-    );
-    model.add_cons(
-        vec![x1.clone(), x2.clone()],
-        &[1., 2.],
-        -f64::INFINITY,
-        80.,
-        "c2",
-    );
+    model.add_cons(vec![&x1, &x2], &[2., 1.], -f64::INFINITY, 100., "c1");
+    model.add_cons(vec![&x1, &x2], &[1., 2.], -f64::INFINITY, 80., "c2");
 
     let solved_model = model.solve();
 
@@ -40,6 +28,6 @@ fn main() {
     let vars = solved_model.vars();
 
     for var in vars {
-        println!("{} = {}", &var.name(), sol.val(var));
+        println!("{} = {}", var.name(), sol.val(&var));
     }
 }

src/col.rs

@@ -239,8 +239,8 @@ mod tests {
         let mut model = minimal_model();
         let x = model.add_var(0.0, 1.0, 1.0, "x", VarType::Binary);
 
-        let cons = model.add_cons(vec![x], &[1.0], 1.0, 1.0, "cons1");
-        model.set_cons_modifiable(cons, true);
+        let cons = model.add_cons(vec![&x], &[1.0], 1.0, 1.0, "cons1");
+        model.set_cons_modifiable(&cons, true);
 
         let eventhdlr = Box::new(ColTesterEventHandler);
         model = model.include_eventhdlr("ColTesterEventHandler", "", eventhdlr);

src/constraint.rs

@@ -3,7 +3,7 @@ use crate::{ffi, Row};
 use std::rc::Rc;
 
 /// A constraint in an optimization problem.
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 #[allow(dead_code)]
 pub struct Constraint {
     /// A pointer to the underlying `SCIP_CONS` C struct.
@@ -54,7 +54,7 @@ mod tests {
             .set_obj_sense(ObjSense::Maximize);
 
         let x1 = model.add_var(0., f64::INFINITY, 3., "x1", VarType::Integer);
-        let cons = model.add_cons(vec![x1], &[1.], 4., 4., "cons");
+        let cons = model.add_cons(vec![&x1], &[1.], 4., 4., "cons");
         drop(model);
 
         assert_eq!(cons.name(), "cons");

src/heuristic.rs

@@ -272,7 +272,7 @@ mod tests {
         ) -> HeurResult {
             let sol = model.create_sol();
             for var in model.vars() {
-                sol.set_val(var, 1.0);
+                sol.set_val(&var, 1.0);
             }
             assert_eq!(sol.obj_val(), 7.0);
             assert_eq!(model.add_sol(sol), Ok(()));