Hi everyone,

I'm working on a formulation related to the Concrete Delivery Problem. I implement the formulation in CPLEX but face some problems with the construction of subset of the sets. For example, I need to construct a set of all subsets of artificial nodes of the graph. What I do is the following:

int st=...;

{int} StartingLocation = asSet(1..st);

int ft=...;

{int} FinishingLocation = asSet(1..ft);

int m2=1; // amount of customer type 2

int m4=1; // amount of customer type 4

{int} Customer2_NOTdefinedCustomers_NONSingleSource = asSet(1..m2);

{int} Customer4_DefinedCustomers_NONsingleSource = asSet(m2..m4+m2);

// Number of actual Customer nodes

{int} Customers = Customer2_NOTdefinedCustomers_NONSingleSource union Customer4_DefinedCustomers_NONsingleSource ;

float Deadline[Customers]= ...; // deadline

float demand[Customers]= ...;

int TimeLag[Customers] = ...;

float DefaultLoadSize = ...;

float LoadPerTrip = ... ;

int definedORnot [Customers] = ...;

int NofArtificialCustomers = 0;

int maxNumber_ofDeliveries[x in Customers];

execute {

for( var l in Customers){

if (definedORnot == 1)

maxNumber_ofDeliveries[l] = Opl.ftoi(Opl.ceil(DefaultLoadSize/demand[l]));

else maxNumber_ofDeliveries[l] = Opl.ftoi(Opl.ceil(demand[l]/LoadPerTrip));

// calculating the number of artificial customer nodes

NofArtificialCustomers = NofArtificialCustomers + maxNumber_ofDeliveries[l];

}

}

int NoCustomers = card(Customers); // the number of Actual nodes for customers

{int} SetofArtCustomerNodes[i in 1..NoCustomers] = asSet(1..maxNumber_ofDeliveries[i]);

// CREATING THE ARTIFICIAL CUSTOMER NODES

tuple artificialnodes {int i ; int j;}

// B: the set of artificial customer nodes

{artificialnodes} Setof_ArtificialCustomers = { | i in Customers, j in SetofArtCustomerNodes[i in Customers]};

int d = ...;

{int} Depots = asSet(m4+m2..d+m4+m2);

{int} SetofArtDepotNodes = asSet(1..NofArtificialCustomers);

// CREATING THE ARTIFICIAL DEPOT NODES

{artificialnodes} Setof_ArtificialDepots = { | i in Depots, j in SetofArtDepotNodes};

int NoV = ...; // amount of vehicles

{int} Vehicles = asSet(1..NoV); // set of vehicles

// CREATING THE ARTIFICIAL STARTING LOCATION NODES

{artificialnodes} Setof_StartingLocations = { | i in Vehicles, j in Customers: j==1};

// CREATING THE ARTIFICIAL FINISHING LOCATION NODES

{artificialnodes} Setof_FinishingLocations = { | i in Vehicles, j in Customers: j==1};

{artificialnodes} N0 = Setof_StartingLocations union Setof_FinishingLocations union Setof_ArtificialDepots union Setof_ArtificialCustomers; // set of Artificialcustomer , depots, starting location , finishing location

However, the usage of union does not have the result I expect.