[Rd] RE: [R] ^ operation much slower in R 1.7.1 than in R 1.7 .0 ???

[Marsland, John]

I have both the CRAN binary and my own compiled version of R v1.7.1 on the
same machine (Dell Pentium III 800 MHz running NT 4)

Using the example provided earlier:

> phi <- 1.6180339887498949
> a <- floor(runif(750000)*1000)
> system.time(b <- (phi^a - (-phi)^(-a))/sqrt(5))[3]

I get 10.99 secs on the CRAN binary and 2.09 secs on my own compiled
version.

I hope this helps someone ... 

Regards,

John Marsland

> -----Original Message-----
> From: Prof Brian D Ripley [mailto:ripley at stats.ox.ac.uk]
> Sent: 05 August 2003 09:03
> To: Philippe Grosjean
> Cc: r-devel at stat.math.ethz.ch
> Subject: [Rd] RE: [R] ^ operation much slower in R 1.7.1 than 
> in R 1.7.0
> ???
> 
> 
> On Tue, 5 Aug 2003, Philippe Grosjean wrote:
> 
> > I propose to move this thread to R-devel...
> >
> > Prof. Brian Ripley wrote:
> > >And are you able to give an explanation?  For example, did 
> you compile
> > >each under the same compiler system?
> >
> > I just noticed that behaviour yesterday, and had not much 
> time yet to
> > investigate it. I compiled 1.7.0 myself (but compared with 
> the binary
> > provided on CRAN; no changes). I used the 1.7.1 binary 
> provided on CRAN. I
> > know these binaries are not supported, so we (Windows 
> users) will have to
> > look at that by ourselve. Indeed yes, I'll first compile 
> 1.7.1 with the same
> > compiler I used for 1.7.0.
> >
> > >I doubt if this is worth R-core's time to pursue, so over 
> to interested
> > >users to find an explanation and fix.
> >
> > OK. But I was wondering if people at R-core team, 
> especially those who
> > worked on Windows specific aspects, would have in mind some 
> changes they did
> > between 1.7.0 and 1.7.1 than can cause this. Since these 
> changes are mainly
> > corrections of bugs, the list is hopefully not so long... 
> and it could help
> > a lot to have these hints. Thanks very much.
> 
> No idea from me, and the effect is not seen on other platforms.
> 
> -- 
> Brian D. Ripley,                  ripley at stats.ox.ac.uk
> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
> University of Oxford,             Tel:  +44 1865 272861 (self)
> 1 South Parks Road,                     +44 1865 272866 (PA)
> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
> 
> ______________________________________________
> R-devel at stat.math.ethz.ch mailing list
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> 


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