
<ConsistencyModule:> +ConX <=> +ConY

   Constraint ConX has the equivalent truth value as ConY.

Arguments
   ConX                Constraint
   ConY                Constraint

Type
   library(gfd)

Description

   Equivalent to BX #= (ConX), BY #= (ConY), BX #= BY
   
   The two constraints are reified in such a way that ConX and ConY constrained
   to the same truth value. ConX and ConY must be constraints that have a 
   corresponding reified form.

   This connective is not available in IC because #=/2 can be used instead.
   It is provided in GFD as it maps directly to gecode's equivalence 
   connective. 

   ConsistencyModule is the optional module specification to give the 
   consistency level for the propagation for this constraint: 
   gfd_bc for bounds consistency, and gfd_gac for domain (generalised arc) 
   consistency. 

   This constraint is implemented using Gecode's MiniModel's rel() for
   both integer and boolean expressions, with sub-expressions/constraints
   not supported by MiniModel factored out and posted as auxiliary 
   constraints.



Modules
   This predicate is sensitive to its module context (tool predicate, see @/2).

See Also
   <=> / 3, neg / 1, or / 2, xor / 2, and / 2, => / 2, suspend : #= / 2, ic : #= / 2, fd : #= / 2
