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Parallel Kit Question: ParallelDot is much more slow than Dot

  • To: mathgroup at smc.vnet.net
  • Subject: [mg40391] Parallel Kit Question: ParallelDot is much more slow than Dot
  • From: "Denis Areshkin" <denis at eos.ncsu.edu>
  • Date: Thu, 3 Apr 2003 01:45:58 -0500 (EST)
  • Organization: NC State University
  • Sender: owner-wri-mathgroup at wolfram.com

Dear All,

I appreciate any response on the following problem:

It appears that  ParrallelDot  function, which is a
part of Parallel Kit, works two orders of magnitude
slower on my two processor machine than Dot.  Below
is the commands used to evaluate dot product in pa-
rallel.  I am not sure that the command

ExportEnvironment[TestMtrx];

is necessary in that case (though it doesn't do any
harm).  It takes 6 seconds to evaluate

Dot[TestMtrx,TestMtrx]

and about half an hour to evaluate

ParallelDot[TestMtrx,TestMtrx]

Needs["Parallel`Parallel`"]

Needs["Parallel`Commands`"]


ProcIDTable = Table[LaunchSlave["localhost",$mathkernel],{2}];


TestMtrx = Table[Random[Real,{-1,1}],{1000},{1000}];


ExportEnvironment[TestMtrx];


TestDot = ParallelDot[TestMtrx,TestMtrx]


I have plenty of RAM (4GB), thus this problem can't
be caused by kernels competing for memory space...

Thank you for your help

--

Denis Areshkin
(919) 513-2424 (office)
(919) 835-1650 (home)



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