Perfect Difference Sets (I just learned) are a math thing; a set of K+1
numbers (K turns out to be an interesting parameter) from the N-1
nonzero residues 1, 2, 3, ..., N-1 of integers modulo N, so that that
every residue is the difference of some pair of numbers in the PD set.
If N = K^2 + K + 1 and K is a power of two it works out, e.g. K = 2, N
= 7 (a prime, so the residues form a finite field, also) e.g. {1, 2,
4} is a PDS mod 7, e.g. 2-4 = -2 = 5 (mod 7). So all of the 6
nonzero residues can be produced by differences of those 3 in the PDS.<br>
But how this is used as a coding for a network topology I have no idea.
The Wolfram site deines PDS as above but doesn't mention networks. <br>
Peter<br><br><div><span class="gmail_quote">On 4/3/08, <b class="gmail_sendername">Douglas Eadline</b> <<a href="mailto:deadline@eadline.org">deadline@eadline.org</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<br> From the EKA Wikipedia article:<br> <br> "The CRL supercomputer has been built using CLOS architecture"<br> <br> Maybe a link to:<br> <br> <a href="http://en.wikipedia.org/wiki/Clos_network">http://en.wikipedia.org/wiki/Clos_network</a><br>
<br> would help the article. I am not sure what they mean<br> by "perfect difference sets". Anyone know?<br> <br> --<br> Doug<br> <br><br> <br> <br> > Slashdot mentioned a cluster topology based on "perfect difference sets"<br>
> used to build EKA, <a href="http://en.wikipedia.org/wiki/EKA_%28supercomputer%29">http://en.wikipedia.org/wiki/EKA_%28supercomputer%29</a><br> > but<br> > the wiki article doesn't mention it. The article<br>
> <a href="http://punetech.com/building-eka-the-worlds-fastest-privately-funded-supercomputer/only">http://punetech.com/building-eka-the-worlds-fastest-privately-funded-supercomputer/only</a><br> > mentions papers that require subscriptions.<br>
> Peter<br> ><br> > On 3/31/08, Rayson Ho <<a href="mailto:raysonlogin@gmail.com">raysonlogin@gmail.com</a>> wrote:<br> >><br> >> You can get detailed information on setting up a BSD HPC cluster at:<br>
>><br> >> <a href="http://people.freebsd.org/~brooks/papers/">http://people.freebsd.org/~brooks/papers/</a><br> >><br> >> Grid Engine was ported and maintained by the author...<br> >><br> >><br>
>> Rayson<br> >><br> >><br> >><br> >><br> >> On Sun, Mar 30, 2008 at 12:12 PM, Israel Lehnen Silva<br> >> <<a href="mailto:israsilva@gmail.com">israsilva@gmail.com</a>> wrote:<br>
>> > Hello friends!<br> >> ><br> >> > I am Brazilian, and i am doing a Beowulf Cluster in OS FreeBSD for a<br> >> > project of University where i study the networking Infrastructure of<br>
>> > the link between the nodes.<br> >> > If someone has other material that can help me, send me for me to<br> >> > increase my project!<br> >> ><br> >> > Counting on the cooperation and support of the brothers.<br>
>> > --<br> >> ><br> >> > Att. Israel Lehnen Silva<br> >> > _______________________________________________<br> >> > Beowulf mailing list, <a href="mailto:Beowulf@beowulf.org">Beowulf@beowulf.org</a><br>
>> > To change your subscription (digest mode or unsubscribe) visit<br> >> <a href="http://www.beowulf.org/mailman/listinfo/beowulf">http://www.beowulf.org/mailman/listinfo/beowulf</a><br> >> ><br>
>> _______________________________________________<br> >> Beowulf mailing list, <a href="mailto:Beowulf@beowulf.org">Beowulf@beowulf.org</a><br> >> To change your subscription (digest mode or unsubscribe) visit<br>
>> <a href="http://www.beowulf.org/mailman/listinfo/beowulf">http://www.beowulf.org/mailman/listinfo/beowulf</a><br> >><br> ><br> ><br> <br>> <br> <br>> _______________________________________________<br>
> Beowulf mailing list, <a href="mailto:Beowulf@beowulf.org">Beowulf@beowulf.org</a><br> > To change your subscription (digest mode or unsubscribe) visit<br> > <a href="http://www.beowulf.org/mailman/listinfo/beowulf">http://www.beowulf.org/mailman/listinfo/beowulf</a><br>
><br> ><br> <br>> !DSPAM:47f4612e224331745845678!<br> ><br> <br><br> <br> --<br> Doug<br> </blockquote></div><br>
!DSPAM:47f53835106198362916074!