This function creates and returns a search selector that implements a minimization search for multithreaded search according to the variable v.

If a variable v appears in more than one agent (that is, more than one worker), then every copy of the variable v must have the same name.

The search selector that this function creates and returns does several things:

• It stores the leaf of the search tree corresponding to the optimal value of the variable v and then reactivates this variable after the complete exploration of the search tree defined by the goal passed to IlcSelectSearch.
• It manages the upper bound on the objective variable. As soon as a solution of value d is found, the constraint v <= d - step is added to the solver for the remainder of the search tree.
• Open nodes are evaluated. The evaluation of an open node is equal to the current minimum of the variable v when the node is created. When the solver asks for an open node, it checks whether the current upper bound on the objective is less than the evaluation of the node. If so, the node is safely discarded.

Implementation

Here we describe important parts of the implementation of this function because it returns an instance of IlcSearchSelector. If you implement your own search selector, then these implementation details may help you determine how your search selector is likely to be used and how it should be implemented.

This function works with the implementation class IlcMTMinimizeIntVarI for constrained variables that are instances of IlcIntVar. The implementation class IlcMTMinimizeIntVarI is a subclass of IlcMTSearchSelectorI. The multithread class IlcMTMinimizeIntVarI differs from its sequential correspondent IlcMinimizeIntVarI in the following ways:

• IlcMTMinimizeIntVarI has an additional data member, _vars of type IlcIntVarRef. This data member stores a reference to all copies of the same variable to facilitate direct, simple access to any one of the copies.
• The constructor of IlcMTMinimizeIntVarI stores the variable with its name when the variable is constructed. When the variable is duplicated, the constructor reads the corresponding reference ( IlcIntVarRef) in this way: