Class: Gecode::Constraints::SetEnum::Selection::IntersectionExpressionStub

Inherits:
Gecode::Constraints::Set::CompositeStub show all
Defined in:
lib/gecoder/interface/constraints/set_enum/selection.rb

Overview

Describes a CompositeStub for the set intersection selection constraint, which constrains the intersection of sets located at the positions specified by a set variable in an enumeration of set variables.

Optionally a universe may also be specified.

Examples

# The sets in the enumeration set variable +sets+ located at the positions
# described by the set variable +selected_sets+ must have an intersection 
# that's a superset of [0,4,17]. 
sets[selected_sets].intersection.must_be.superset_of [0,4,17]

# The sets in the enumeration set variable +sets+ located at the positions
# described by the set variable +selected_sets+ must have an intersection
# that's disjoint with the set variable +set+.
sets[selected_sets].intersection.must_be.disjoint_with set

# The sets in the enumeration set variable +sets+ located at the positions
# described by the set variable +selected_sets+ must have an intersection
# that's disjoint with the set variable +set+ inside the universe 0..17.
sets[selected_sets].intersection(:with => 0..17).must_be.disjoint_with set

# The sets in the enumeration set variable +sets+ located at the positions
# described by the set variable +selected_sets+ must have an intersection
# that's disjoint with the set variable +set+ inside the universe 
# described by the set variable +universe+.
sets[selected_sets].intersection(:with => universe).must_be.disjoint_with set

# The same as above but reified with the boolean variable 
# +intersection_is_disjoint+.
sets[selected_sets].intersection(:with => universe).must_be.disjoint_with(
  set, :reifty => intersection_is_disjoin)

Instance Method Summary collapse

Methods inherited from Gecode::Constraints::Set::CompositeStub

#initialize

Methods inherited from CompositeStub

#initialize

Methods included from LeftHandSideMethods

#must, #must_not

Methods inherited from ExpressionStub

#initialize

Constructor Details

This class inherits a constructor from Gecode::Constraints::Set::CompositeStub

Instance Method Details

#constrain_equal(variable, params, constrain) ⇒ Object 



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# File 'lib/gecoder/interface/constraints/set_enum/selection.rb', line 184

def constrain_equal(variable, params, constrain)
  enum, indices, universe = @params.values_at(:lhs, :indices, :universe)
  # We can't do any useful constraining here since the empty intersection
  # is the universe.
  
  if universe.nil?
    Gecode::Raw::selectInter(@model.active_space, enum.to_set_var_array,
      indices.bind, variable.bind)
  else
    Gecode::Raw::selectInterIn(@model.active_space, enum.to_set_var_array,
      indices.bind, variable.bind, 
      Gecode::Constraints::Util.constant_set_to_int_set(universe))
  end
end