simultaneous multiple key sorting algorithm
Manfred Nowak
svv1999 at hotmail.com
Sat Jan 28 07:10:08 PST 2012
Andrei Alexandrescu wrote:
[ About ranks]
> Actually they need to be computed.
Then the problem is still too unclear.
> I think it's possible to find cases where
> rank(a, k1) + rank(a, k2) < rank(b, k1) + rank(b, k2)
> but
> alpha * a.k1 + beta * a.k2 > alpha * b.k1 + beta.k2.
Of course. Especially if the a, b, ... are sortable only partielly.
But if the ranks are known, the problem can be finished with the
linear median algorithm.
> One potentially confusing issue is that importance applies to
> rank, not features.
Do you mean that
alpha * rank(a, k1) + beta * rank(a, k2)
has to be extremized for all `a'?
Again: the problem is still unclear.
-manfred
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