Class: Gecode::Constraints::Set::Relation::ElementRelationConstraint

Inherits:
Constraint
  • Object
show all
Defined in:
lib/gecoder/interface/constraints/set/relation.rb

Overview

Describes an element relation constraint which constrains all elements in a set variable to satisfy an integer relation constraint. The relations supported are the same as in Int::Linear::SimpleRelationConstraint.

Reification is not supported.

Examples

# All elements in +set+ must be larger than 5.
set.elements.must > 5

# No element in +set+ may equal 0.
set.elements.must_not == 0

# No element in +set+ may contain the value of the integer variable
# +forbidden_number+.
set.elements.must_not == forbidden_number

Instance Method Summary collapse

Methods inherited from Constraint

#initialize

Constructor Details

This class inherits a constructor from Gecode::Constraints::Constraint

Instance Method Details

#post ⇒ Object 



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# File 'lib/gecoder/interface/constraints/set/relation.rb', line 142

def post
  var, rhs, relation = @params.values_at(:lhs, :rhs, :relation)
  
  if @params[:negate]
    type = Gecode::Constraints::Util::NEGATED_RELATION_TYPES[relation]
  else
    type = Gecode::Constraints::Util::RELATION_TYPES[relation]
  end

  if rhs.kind_of? Fixnum
    # Use a proxy int variable to cover.
    rhs = @model.int_var(rhs)
  end
  Gecode::Raw::rel(@model.active_space, var.bind, type, rhs.bind)
end