Hello Harmut, This looks useful. I have several questions:
The requirement, that the input keys should be strictly positive isn't a big limitation, because it is always possible to accordingly transform key sets containing possibly negative numbers, ...
? By addition of a constant positive offset?
or to derive the keys from strings to match.
? You lost me here. Would you explain this point in a little more detail please.
The memory requirement for the MPH generator is raising linearily with the number of keys: roughly N/3 * sizeof(int), where N is the number of keys.
? Is it possible to generalize to keys outside of unsigned int's range w/linear impact on generator performance? Specifically, I'm looking for an efficient hash function for an associative hash table keyed by 16-byte UUID's where I know the set of UUID keys a-priori, hash lookup time is constant (primary consideration), hash generation time is linear (secondary consideration). - Regards Chris "Hartmut Kaiser" <hartmutkaiser@t-online.de> wrote in message news:1CqRR7-1vg7iS0@afwd00.sul.t-online.com...
Hi all,
recently I've written a minimal perfect hash function generator, which generates very efficient hashing functions for arbitrary (reasonable large) key sets containing strictly positive integers to achieve a minimal and perfect mapping of these keys to hash values in the range [0..N), where N is the size of the key set (minimality requirement) and the hash values are unique (perfection requirement).