Petr, Thank you for your reply, I actually figured out the issue this morning, I needed to add more data to my data file and it resolved it.
Thanks again for everyones time! Jason On Nov 2, 2012, at 9:00 AM, PIKAL Petr wrote: > Hi > >> >> Jim, >> >> Thank you for your reply. I guess I am just not understanding what the >> difference is. If I run your example using the pcmatrix<- >> data.frame(Q1=sample(1:5,10,TRUE),Q2=sample(1:5,10,TRUE)) and print out >> pcmatrix I get: >> >> Q1 Q2 >> 1 98 99 > > Thats rather surprising. I get > >> pcmatrix<-data.frame(Q1=sample(1:5,10,TRUE),Q2=sample(1:5,10,TRUE)) >> pcmatrix > Q1 Q2 > 1 4 4 > 2 3 3 > 3 4 1 > 4 4 4 > 5 4 2 > 6.... > > this what I get > > >> >> Then if I mirror my input file to be, would would be what the samples >> from above would have created, it would look like this: >> >> ID,Q1,Q2 >> 1,2,3 > > what about include > > dput(head(yourfile)) > to your post to let us see how it looks like. Or at least > > str(yourfile) > > Regards > Petr > > >> >> And I run the script printing out pcmatrix I get the exact same thing. >> >> Q1 Q2 >> 1 98 99 >> >> So I would think they are basically the same representations, however >> one works when passed into the prcomp function and the other does not. >> I am just trying to tweak a script that we had created for us (cannot >> find the guy now) so I can pass more columns of data. I clearly really >> do not know what I am doing, but again thanks for you time and any >> direction you can point me in would be awesome. >> >> Thanks >> >> Jason >> >> On Nov 1, 2012, at 3:57 AM, Jim Lemon wrote: >> >>> On 10/31/2012 11:47 PM, fillay89 wrote: >>>> I am trying to run the R Script below, I have actually simplified it >>>> to just this part that is causing issues. When I run this script I >>>> continue to get an error that says "cannot rescale a constant/zero >>>> column to a unit variance". I cannot figure out what is going on >>>> here. I have stripped down my data file so it is more manageable so >> I can try to figure this out. >>>> >>>> The data.txt file that is being read looks like this: >>>> >>>> >>>> I have made this file very basic on purpose to see if I could get >>>> this to work, but it is not working. Of course once I get this to >>>> actually work I will expand the data file to match the data I am >> actually using. >>>> >>>> >>>> >>>> If I change the attribute in the prcomp function to scale=FALSE of >>>> course I can run my script. But if it is scaling...which is causing >>>> the issues, it errors. >>>> >>>> Any help would be GREATLY appreciated. >>>> >>> Hi fillay89, >>> You seem to be trying to run a principal component analysis on two >> numbers, which won't produce anything useful. If I make up some data >> that is more realistic: >>> >>> pcmatrix<-data.frame(Q1=sample(1:5,10,TRUE),Q2=sample(1:5,10,TRUE)) >>> pcmatrix[,1] <- pcmatrix[,1] + 96 >>> pcmatrix[,2] <- pcmatrix[,2] + 96 >>> x.pca <- prcomp(pcmatrix,retx=TRUE,center=TRUE,scale=TRUE,cor=TRUE) >>> x.pca >>> Standard deviations: >>> [1] 1.263267 0.635733 >>> >>> Rotation: >>> PC1 PC2 >>> Q1 0.7071068 -0.7071068 >>> Q2 0.7071068 0.7071068 >>> >>> it runs and I get a slightly more useful result. Running your code >> does bomb in exactly the way you describe, as does: >>> >>> x.pca <- prcomp(data.frame(Q1=99,Q2=98), retx=TRUE, center=TRUE, >>> scale=TRUE, cor=TRUE) Error in prcomp.default(data.frame(Q1 = 99, Q2 >> = 98), retx = TRUE, center = TRUE, : >>> cannot rescale a constant/zero column to unit variance >>> >>> Your problem is that you have a data frame with only one value (i.e. >> a constant) in each column. >>> >>> Jim >> >> ______________________________________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide http://www.R-project.org/posting- >> guide.html >> and provide commented, minimal, self-contained, reproducible code. > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
