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<div class="moz-cite-prefix">On 4/20/20 11:58 PM, wrote:<br>
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I was going to ask this question during class, but I'll go ahead
and ask it now since I plan to get some good work done Tuesday.
Once we find the optimal number of nodes to use, do we just need
to then determine the optimal number of threads? Or is it one of
those things where one affects the other so you still have to
test? Thanks, see you Wednesday.</div>
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<p>Yes -- this is one of those things that you have to test.
Essentially you are trying to minimize a function with the matrix
size being a parameter and the number or systems and number of
processors per system being arguments. The results depend on type
of processor, cache layout, memory hierarchy, network type, and
network speed.</p>
<p>I mean think about it, if you had a slow network and really fast
processors, then you may only want to use a few systems. If you
had something like a myrinet or infiniband based network then you
may want to push the data out to more systems and use fewer
threads on each system.</p>
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<p>You will all need to run numerous tests -- so this is not
something to wait on. <br>
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<p>I will have to make a short trip to campus today and I will reset
the system that fell off the network in lab 218.</p>
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<pre class="moz-signature" cols="72">--
Andrew J. Pounds, Ph.D. (<a class="moz-txt-link-abbreviated" href="mailto:pounds_aj@mercer.edu">pounds_aj@mercer.edu</a>)
Professor of Chemistry and Computer Science
Director of the Computational Science Program
Mercer University, Macon, GA 31207 (478) 301-5627
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