The root page 15DOTs60ia13:Tutorial could not be found in space 15.S60 SSIM: Software Tools for Operations Research.
Problem Formulation
First, we will add the following fields to the class so we can easily reference our problem data from any method. Add
private EnumSet<Option> options; private IloCplex cplex; private TspInstance<V,E> tspInstance; private ImmutableBiMap<E,IloIntVar> edgeVariables;
and initialize them, as below.
public TspIpSolver(TspInstance<V,E> tspInstance, EnumSet<Option> options) throws IloException{ this.options = options; this.tspInstance = tspInstance; this.cplex = new IloCplex(); UndirectedGraph<V,E> graph = tspInstance.getGraph(); //for convenience, we will be using this a lot this.edgeVariables = Util.makeBinaryVariables(cplex, graph.getEdges()); //the degree constraints //the objective }
Next, we need to add the objective and the degree constraints to the IloCplex
instance. Try adding them yourself! The following methods (as defined in Solver Specification and Java Style for CPLEX) should be useful for making the degree constraints:
- From
Util
, the static methodintegerSum(IloCplex cplex, BiMap<T,IloIntVar> variables, Iterable<T> set)
- From
IloCplex
, the methodaddEq(IloNumExpr e, double v)
- From
UndirectedGraph<V,E>
, the methodgetIncidentEdges(V vertex)
Solution
For the objective, we need the functions:
- From
Util
, the static methodsum(IloCplex cplex, BiMap<T,IloIntVar> variables, Iterable<T> set, Function<? super T,? extends Number> coefficients)
- From
UndirectedGraph<V,E>
, the methodgetEdges()
- From
TspInstance
, the methodgetEdgeWeights
Solution