I am using a sum of squared differences in the objective function of an
optimization problem I am doing and I have managed to speed it up using
the outer function versus the nested for loops, but my suspicion is
that the calculation could be done even quicker. Please see the code
below for a
Conclusion: hard to beat outer() for this purpose in R
... unless you use Ken Knoblauch's suggestion of dist() or Rccp.
Nice indeed.
S Ellison
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This email and any attachments are confidential. Any use...{{dropped:8}}
Actually, you don't need to use c() in the dist example, either, which
should shave off a few microseconds for a function call. It was late
last night ...
Ken
On 22-10-2013 15:08, S Ellison wrote:
Conclusion: hard to beat outer() for this purpose in R
... unless you use Ken Knoblauch's
Cc: r-help@r-project.org
Subject: Re: [R] speeding up sum of squared differences calculation
Actually, you don't need to use c() in the dist example, either, which should
shave off a few microseconds for a function call. It was late last night ...
Ken
On 22-10-2013 15:08, S Ellison wrote
There's little practical difference; both hover from 0.00 to 0.03 s system
time. I could barely tell the difference even averaged over 100 runs; I was
getting an average around 0.007 (system time) and 2.5s user time for both
methods.
It's almost always better to use a high precision timer,
wdunlap tibco.com
-Original Message-
From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On
Behalf
Of S Ellison
Sent: Tuesday, October 22, 2013 6:08 AM
To: r-help@r-project.org
Cc: Ken Knoblauch
Subject: Re: [R] speeding up sum of squared differences calculation
All,
I am using a sum of squared differences in the objective function of an
optimization problem I am doing and I have managed to speed it up using the
outer function versus the nested for loops, but my suspicion is that the
calculation could be done even quicker. Please see the code below
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