Re: efficient compare
From: Frank Hamersley <terabitemightbe_at_bigpond.com>
Date: Sun, 23 Apr 2006 08:23:59 GMT
Message-ID: <zQG2g.13583$vy1.13114_at_news-server.bigpond.net.au>
>
> You are not going to get log(N) in messages either.
>
>
> But you said N is a large number which means you have to send a large
> number of checksums.
Date: Sun, 23 Apr 2006 08:23:59 GMT
Message-ID: <zQG2g.13583$vy1.13114_at_news-server.bigpond.net.au>
Bob Badour wrote:
> Andersen wrote:
>
>> Bob Badour wrote: >> >>> I don't see how you are going to get log(N). >> >> log(N) message exchanges! Not bit complexity (i.e. size of the messages).
>
> You are not going to get log(N) in messages either.
>
>>> Consider A & B are equal each with 65535 tuples. Insert a tuple into >>> A at the beginning of the sort order. Insert a tuple into B at the >>> end of the sort order. >>> >>> None of your subdivided sets are going to give matching checksums >>> except in error until you get down to individual tuples. >> >> Here is a different solution to that problem. Keep N bins, where N is >> some very large constant. Hash every tuple to an integer between 1-N >> and put it in the corresponding bin. Now run the divide and conquer on >> this. >> >> I.e, first send checksum of the value of all bins
>
> But you said N is a large number which means you have to send a large
> number of checksums.
Cheers, Frank. Received on Sun Apr 23 2006 - 10:23:59 CEST