Class: ConstraintSolver::AbstractConstraint

Inherits:
Object
  • Object
show all
Defined in:
lib/AbstractConstraint.rb

Overview

Represents a constraint. To be used as a guidance to see which methods constraints need to implement.

Instance Method Summary collapse

Instance Method Details

#allAssigned? ⇒ Boolean

Checks whether all variables involved in the constraint have values assigned to them.

Returns:

  • (Boolean)

Raises:

  • (RuntimeError) 


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# File 'lib/AbstractConstraint.rb', line 15

def allAssigned?
    raise RuntimeError, "must implement allAssigned?"
end

#each ⇒ Object

Iterates over all the variables involved in the constraint.

Raises:

  • (RuntimeError) 


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# File 'lib/AbstractConstraint.rb', line 25

def each
    raise RuntimeError, "must implement each"
end

#holds? ⇒ Boolean

Checks whether the constraint holds for the current assignments of the involved variables.

Returns:

  • (Boolean)

Raises:

  • (RuntimeError) 


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# File 'lib/AbstractConstraint.rb', line 9

def holds?
    raise RuntimeError, "must implement holds?"
end

#include?(variable) ⇒ Boolean

Checks whether the constraint includes variable.

Returns:

  • (Boolean)

Raises:

  • (RuntimeError) 


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# File 'lib/AbstractConstraint.rb', line 20

def include?(variable)
    raise RuntimeError, "must implement include?(variable)"
end

#revise ⇒ Object

Prunes the values from the domains of the involved variables that cannot be assigned to the respective variables because the constraint would be violated. Returns a list of the variables whose domains were pruned, the number of times the constraint was checked, and whether a domain wipeout occured.

Raises:

  • (RuntimeError) 


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# File 'lib/AbstractConstraint.rb', line 34

def revise
    raise RuntimeError, "must implement revise"
end

#violationCost ⇒ Object

Returns the cost of violating the constraint. This should be infinity (or reasonably close to it) for hard constraints and a positive number for soft constraints.

Raises:

  • (RuntimeError) 


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# File 'lib/AbstractConstraint.rb', line 41

def violationCost
    raise RuntimeError, "must implement violationCost"
end