<div>But oh and Jim if you recall any papers about this I could read that would be "Jim" Dandy.</div>
<div>Peter<br><br> </div>
<div><span class="gmail_quote">On 5/23/07, <b class="gmail_sendername">Jim Lux</b> <<a href="mailto:James.P.Lux@jpl.nasa.gov">James.P.Lux@jpl.nasa.gov</a>> wrote:</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<div><span class="q">At 09:19 AM 5/22/2007, Peter St. John wrote:<br>
<blockquote cite="http://" type="cite">A hypercube (<a onclick="return top.js.OpenExtLink(window,event,this)" href="http://en.wikipedia.org/wiki/Hypercube" target="_blank"> http://en.wikipedia.org/wiki/Hypercube</a>) also gets you exponential space; the max hops is the dimension (3 for a 3-dimensional cube) and the number of nodes is exp(base 2) of the dimension (8 vertices on a cube). To do a tesseract (4-cube), which looks like two cubes nested, you'd need 4 ports per node, 16 nodes, 32 cables, max hop 4. I've poked around and don't see a great 4 ports per node solution; I like the suggestion of putting a router on a motherboard.
</blockquote><br></span>Mind you, this is what Intel started with on their iPSC/1 and iPSC/2 computers. The early ones had multiple NICs in the nodes, then, later, they had a 8 port (I think) router in each node.<br><br>
It's not clear that this saves anything over a simpler architecture (e.g. external switch with lots of ports in a crossbar) unless you can do circuit switched routing (so you don't have a one packet delay in the switch) AND your algorithm can take advantage of it. I spent quite some time in the late 80s trying to figure out clever ways to take advantage of a hypercube topology for a modeling application.. I'm sure there are algorithms which are a natural fit, but the ones I was using weren't.
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<p>James Lux, P.E.<br>Spacecraft Radio Frequency Subsystems Group<br>Flight Communications Systems Section<br>Jet Propulsion Laboratory, Mail Stop 161-213<br>4800 Oak Grove Drive<br>Pasadena CA 91109<br>tel: (818)354-2075
<br>fax: (818)393-6875</p></div></blockquote></div><br>
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