Class: Gecode::Bool::BoolConstraintReceiver

Inherits:
ConstraintReceiver show all
Defined in:
lib/gecoder/interface/constraints/bool_var_constraints.rb,
lib/gecoder/interface/constraints/bool/boolean.rb,
lib/gecoder/interface/constraints/bool/channel.rb

Overview

BoolConstraintReceiver contains all constraints that can be placed on a BoolOperand.

Constraints are placed by calling BoolOperand#must (or any other of the variations defined in Operand), which produces a BoolConstraintReceiver from which the desired constraint can be used.

Each constraint accepts a number of options. See ConstraintReceiver for more information.

Examples

Constrains bool_operand to be true using BoolConstraintReceiver#true:

bool_operand.must_be.true

Constrains bool_operand1 AND bool_operand2 to be true using the BoolOperand#& property and BoolConstraintReceiver#true:

(bool_operand1 & bool_operand2).must_be.true

Constrains the conjunction of all boolean operands in bool_enum to not imply bool_operand using the BoolEnumOperand#conjunction property and BoolConstraintReceiver#imply:

bool_enum.conjunction.must_not.imply bool_operand

The same as above, but specifying that strength :domain should be used and that the constraint should be reified with bool_operand2:

bool_enum.conjunction.must_not.imply(bool_operand, :strength => :domain, :reify => bool_operand2)

Instance Method Summary collapse

Constructor Details

#initialize(model, params) ⇒ BoolConstraintReceiver

Raises TypeError unless the left hand side is an bool operand.



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# File 'lib/gecoder/interface/constraints/bool_var_constraints.rb', line 86

def initialize(model, params) #:nodoc:
  super

  unless params[:lhs].respond_to? :to_bool_var
    raise TypeError, 'Must have bool operand as left hand side.'
  end
end

Instance Method Details

#==(bool_op, options = {}) ⇒ Object

Constrains the boolean operand to be equal to bool_op. Any of ==, equal and equal_to may be used for equality.

Examples

b1 and b2 must equal b1 or b2.

(b1 & b2).must == (b1 | b2)

b1 and b2 must not equal b3. We reify it with bool and select

the strength domain.

(b1 & b2).must_not.equal(b3, :reify => bool, :select => :domain)



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# File 'lib/gecoder/interface/constraints/bool/boolean.rb', line 72

def ==(bool_op, options = {})
  unless bool_op.respond_to? :to_minimodel_bool_expr
    bool_op = ExpressionNode.new(bool_op, @model)
  end
  @params.update Gecode::Util.decode_options(options)
  @params.update(:lhs => @params[:lhs], :rhs => bool_op)
  @model.add_constraint BooleanConstraint.new(@model, @params)
end

#false(options = {}) ⇒ Object

Constrains the boolean operand to be false.

Examples

b1 and b2 must be false.

(b1 & b2).must_be.false

(+b1+ implies b2) and (+b3+ implies b2) must be false.

((b1.implies b2) & (b3.implies b2)).must_be.false

b1 and b2 must be false. We reify it with bool and select the

strength domain.

(b1 & b2).must_be.false(:reify => bool, :strength => :domain)



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# File 'lib/gecoder/interface/constraints/bool/boolean.rb', line 130

def false(options = {})
  @params[:negate] = !@params[:negate]
  self.true(options)
end

#imply(bool_op, options = {}) ⇒ Object

Constrains the boolean operand to imply bool_op.

Examples

b1 must imply b2

b1.must.imply b2

b1 and b2 must not imply b3. We reify it with bool and select

domain as strength.

(b1 & b2).must_not.imply(b3, :reify => bool, :strength => :domain)



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# File 'lib/gecoder/interface/constraints/bool/boolean.rb', line 92

def imply(bool_op, options = {})
  @params.update Gecode::Util.decode_options(options)
  @params.update(:lhs => @params[:lhs].implies(bool_op), :rhs => true)
  @model.add_constraint BooleanConstraint.new(@model, @params)
end

#true(options = {}) ⇒ Object

Constrains the boolean operand to be true.

Examples

b1 and b2 must be true.

(b1 & b2).must_be.true

(+b1+ implies b2) and (+b3+ implies b2) must be true.

((b1.implies b2) & (b3.implies b2)).must_be.true

b1 and b2 must be true. We reify it with bool and select the

strength domain.

(b1 & b2).must_be.true(:reify => bool, :strength => :domain)



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# File 'lib/gecoder/interface/constraints/bool/boolean.rb', line 111

def true(options = {})
  @params.update Gecode::Util.decode_options(options)
  @model.add_constraint BooleanConstraint.new(@model, 
    @params.update(:rhs => true))
end