  Some techniques for the use of bitwise operations are described in the
article. As an example, an open problem of isomorphism-free generations of
combinatorial objects is discussed. An equivalence relation on the set of
square binary matrices having the same number of units in each row and each
column is defined. Each binary matrix is represented using ordered n-tuples of
natural numbers. It is shown how by using the bitwise operations can be
implemented an algorithm that gets canonical representatives which are extremal
elements of equivalence classes relative to a double order on the set of
considered objects.
