Merge pull request #18 from scipopt/var-isvoid

Add Var::isVoid

Author: hedtke

include/scippp/var.hpp

@@ -48,6 +48,13 @@ struct Var {
      * @return \c true iff the value of this variable in the primal solution is in range epsilon of 0.0.
      */
     [[nodiscard]] bool isZero(const Solution& solution) const;
+
+    /**
+     * Checks whether an existing %SCIP variable is wrapped or the wrapper is empty.
+     * @since 1.2.0
+     * @return \c true iff the wrapper is empty
+     */
+    [[nodiscard]] bool isVoid() const;
 };
 
 }

source/var.cpp

@@ -26,4 +26,9 @@ bool Var::isZero(const Solution& solution) const
     return SCIPisZero(solution.scip, getSolVal(solution));
 }
 
+bool Var::isVoid() const
+{
+    return var == nullptr;
+}
+
 }

test/test_var.cpp

@@ -62,4 +62,16 @@ BOOST_AUTO_TEST_CASE(IsZero)
     BOOST_TEST(model.isZero(x1.getSolVal(sol)));
 }
 
+BOOST_AUTO_TEST_CASE(IsVoid)
+{
+    scippp::Var x;
+    BOOST_TEST(x.var == nullptr);
+    BOOST_TEST(x.isVoid());
+
+    Model model("Simple");
+    auto x1 = model.addVar("x_1", 1);
+    BOOST_TEST(x1.var != nullptr);
+    BOOST_TEST(!x1.isVoid());
+}
+
 BOOST_AUTO_TEST_SUITE_END()