Module variable_selection

Provides the VariableSelector trait which is required for variable selectors to implement; the main method in this trait relies on VariableSelector::select_variable.

Furthermore, it defines several implementations of the VariableSelector trait such as Vsids. Any VariableSelector should only select variables which have a domain of size 2 or larger.

Structs

• AntiFirstFail
  A VariableSelector which selects the variable with the largest domain (based on the lower-bound and upper-bound, disregarding holes).
• DynamicVariableSelector
  Similar to DynamicBrancher, this is a pass-along structure which should be used when a Sized object is required.
• FirstFail
  A VariableSelector which selects the variable with the smallest domain (based on the lower-bound and upper-bound, disregarding holes).
• InputOrder
  A VariableSelector which selects the first variable which is not fixed given the order in the provided list.
• Largest
  A VariableSelector which selects the variable with the largest value in its domain.
• MaxRegret
  A VariableSelector which selects the variable with the largest difference between the two smallest values in its domain.
• MostConstrained
  A VariableSelector which selects the variable with the smallest domain (similar to FirstFail).
• Occurrence
  A VariableSelector which selects the variable with the largest number of attached constraints (where the provided num_occurrences stores the number of attached constraints per variable).
• Smallest
  A VariableSelector which selects the variable with the smallest value in its domain.
• Vsids
  A VariableSelector which implements VSIDS [1].

Traits

• VariableSelector
  A trait containing the interface for VariableSelectors, specifying the appropriate hooks into the solver and the methods required for selecting variables.