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- To: PRATT at MIT-MC, (BUG LISP) at MIT-MC, MACRAK at MIT-MC
- Subject: Hashing structures.
- From: MACRAK at MIT-MC (Stavros M. Macrakis)
- Date: Fri, 21 Dec 79 22:03:00 GMT
- Original-date: 21 DEC 1979 1703-EST
I agree that the current SXHash is rather poor. But all schemes based on
the recursion step R(a,x)+R(b,y) are bound to lose, since it is so often
true that R(a+b,x)=R(a,x)+R(b,x), where R(a,x) is a rotated x positions.
Equal rotations tend to happen through the tree.
Some algebraic insight is missing here. Some sort of easily-computable
finite binary operator with few identities is needed. Ideas?