Three responses:
Yes, 61, which is prime, is better than 64 = 2^6, which is composite.
A binary search/chop is easy when one has all of the values one is going to
search for compresent and available to be put into a table. When one is
acquiring these values serially in time, a binary-search tree can be used
instead; but it must be kept balanced/compact; and this is a non-trivial
undertaking. For many applications--compiler and assembler symbol tables are
the obvious example--a set of ordered sublists, one for each hash value, yields
faster results. Much depends upon what you have in hand in the way of already
working routines.
If division-method hashing is used a prime divisor/modulus is highly desirable.
Clustering at the prime divisors of a composite modulus does occur. I dislike
arguments from authority, but 1) this is not the place for a bibliography and
2) RKFATWTF.
John Gilmore Ashland, MA 01721-1817 USA
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