Re: [R] Different results under Windows and Linux

From: Kamila Naxerova <kamila.naxerova_at_childrens.harvard.edu>
Date: Wed 19 Apr 2006 - 09:58:02 EST

Thanks Bert, I did not describe the problem accurately enough.

Actually, by now, I found out that floating-point imprecision is the reason for my confusion. The problem does not arise with the prcomp() function but rather with my data preprocessing:

 > means=apply(dev,2,mean,na.rm=T)
 > means
windows 371.19100102494, 432.458908438674 etc. linux 371.191001024941,432.458908438674 etc.

 > stdev=apply(dev,2,sd,na.rm=T)
 > stdev
windows 872.234567580374, 1324.05572667875 etc. linux 872.234567580372, 1324.05572667875 etc.

Thanks!
Kamila

Berton Gunter wrote:

>Please provide better documentation to help diagnose the problem. What are
>the PC's ?
>
>-- Bert Gunter
>Genentech Non-Clinical Statistics
>South San Francisco, CA
>
>"The business of the statistician is to catalyze the scientific learning
>process." - George E. P. Box
>
>
>
>
>
>>-----Original Message-----
>>From: r-help-bounces@stat.math.ethz.ch
>>[mailto:r-help-bounces@stat.math.ethz.ch] On Behalf Of Kamila Naxerova
>>Sent: Tuesday, April 18, 2006 3:12 PM
>>To: r-help@stat.math.ethz.ch
>>Subject: [R] Different results under Windows and Linux
>>
>>Hi everyone,
>>
>>disturbingly, a PCA yields different results when I run the analysis
>>under Windows and Linux.
>>I open the same workspace (which is on an independent partition) and
>>perform the exact same function (by using the history file).
>>Interestingly, PC1 is the same, but PC2 comes out totally different.
>>
>>Thanks!
>>Kamila
>>
>>Windows:
>>platform i386-pc-mingw32
>>arch i386
>>os mingw32
>>system i386, mingw32
>>status
>>major 2
>>minor 2.1
>>year 2005
>>month 12
>>day 20
>>svn rev 36812
>>language R
>>
>>
>>Linux (Suse 10, Kernel 2.6.13-15.8-default)
>>platform i686-pc-linux-gnu
>>arch i686
>>os linux-gnu
>>system i686, linux-gnu
>>status
>>major 2
>>minor 2.1
>>year 2005
>>month 12
>>day 20
>>svn rev 36812
>>language R
>>
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>>PLEASE do read the posting guide!
>>http://www.R-project.org/posting-guide.html
>>
>>
>>
>
>
>
>
>



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