[ library(gfd) | Reference Manual | Alphabetic Index ]

# lex_eq(+Collection1, +Collection2)

Collection1 is lexicographically equal to Collection2

Collection1
  Collection of integers or (domain) variables
Collection2
  Collection of integers or (domain) variables

## Description

Constrains the two collections to be lexicographically equal, i.e. the two collections are the same length, and each element is identical to its corresponding element in the other collection.

This constraint is known as lex_equal in the global constraint catalog, but the catalog's definition requires Collection1 and Collection2 to be the same size. It is implemented using Gecode's rel() constraint (variant that takes two IntVarArgs arguments), with the IRT_EQ IntRelType.

## Examples

    [eclipse 48]: lex_eq([1,9,1,5], [1,9,1,5]).

    ...
    Yes (0.00s cpu)
    [eclipse 49]: lex_eq([1,9,1,5], [1,9,2,5]).

    No (0.00s cpu)
    [eclipse 50]: lex_eq([1,9,1,5], [1,9,0,5]).

    No (0.00s cpu)
    [eclipse 51]: lex_eq([1,9,1], [1,9,1,5]).

    No (0.00s cpu)

## See Also

lex_lt / 2, lex_gt / 2, lex_ge / 2, lex_ne / 2