+/// Tolerance for value of parameters
+const double tolerance = 1.e-10;
+
+#define PI 3.1415926535897932
+
+// Types for data entities enumeration
+typedef size_t GroupID;
+typedef size_t ParameterID;
+typedef size_t EntityID;
+typedef size_t ConstraintID;
+
+// Predefined values for identifiers
+const GroupID GID_UNKNOWN = 0;
+const GroupID GID_OUTOFGROUP = 1;
+
+const ParameterID PID_UNKNOWN = 0;
+const EntityID EID_UNKNOWN = 0;
+const ConstraintID CID_UNKNOWN = 0;
+