Hello
i need some precision about nipals in the chemometrics package in R .
When i use nipals in chemometrics i obtain T and P matrix.
I really don't understand what to do with these two matrix to obtain
the scores for every the component (like in spss fo example)
Comp1 Comp2 Comp3
quest1 0,8434 0,54333 0,3466
quest2 0,665 0,7655 0,433
Thank you very much for your help
(I know that X=TP+E)... But don't understand else....
zz dd: If you want a typical score plot, say PC1 vs PC2, then plot the first and second columns of your score matrix (T) against each other and label the points with the row names (if available) or create a text label from where ever you have this information stored. To get an unlabeled score plot, you could simply do: plot(T[,1], T[,2]) If you are using the package chemometrics, you should take a look at the book that goes with it too: Varmuza and Filzmoser, "Multivariate Statistical Analysis in Chemometrics". If you need more guidance than this, you should probably give us more details about what you are doing. Bryan **************** Prof. Bryan Hanson Dept of Chemistry & Biochemistry DePauw University Greencastle IN 46135 USA academic.depauw.edu/~hanson/deadpezsociety.html github.com/bryanhanson academic.depauw.edu/~hanson/UMP/Index.html On Dec 1, 2011, at 6:51 AM, zz dd wrote:> Hello > i need some precision about nipals in the chemometrics package in R . > > When i use nipals in chemometrics i obtain T and P matrix. > > I really don't understand what to do with these two matrix to obtain > the scores for every the component (like in spss fo example) > > Comp1 Comp2 Comp3 > quest1 0,8434 0,54333 0,3466 > quest2 0,665 0,7655 0,433 > > Thank you very much for your help > (I know that X=TP+E)... But don't understand else.... > > ______________________________________________ > R-help at 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.
Hello The solution maybe there but i need to compute it into R if someone can help me : (Previously store score vector t in score matrix T; store loading vector p in loading matrix P) that's done by nipals in chemometrics After use of nipals function you have T and P matrix First : "Calculate the residual matrix of X. Stop if the elements of Xres are very small because no further PCA components are reasonable" : Xres= X-u.b(T) u : improved score vector b: loading vector X : a mean-centered matrix Second : Replace X with Xres and continue with step 2 (with nipals chemometrics...) for calculation of the next PCA component. If someone can help me ? Thank's a lot 2011/12/1 zz dd <void1999@gmail.com>> Hello > i need some precision about nipals in the chemometrics package in R . > > When i use nipals in chemometrics i obtain T and P matrix. > > I really don't understand what to do with these two matrix to obtain > the scores for every the component (like in spss fo example) > > Comp1 Comp2 Comp3 > quest1 0,8434 0,54333 0,3466 > quest2 0,665 0,7655 0,433 > > Thank you very much for your help > (I know that X=TP+E)... But don't understand else.... >[[alternative HTML version deleted]]