 

________________________________

De: Trochine, Carolina
Enviado el: mar 23/10/2007 13:45
Para: r-help@lists.R-project.org
Asunto: Multivariate regression tree: problems with surrogate splits


R helpers,

I am working with the R program performing multivariate regression trees (MRT). I have a matrix with species and environmental variables saved as a CSV file (sprot_matrix.csv), I have 42 species and 8 environmental variables (SECCHI+PH+TA+PTOT+NTOT+CHLA+AREA+ MEANDEP) for 104 samples



Title

SpA

SpB

SpC

SpD

Varible1

Variable2

Variable3

Sample1















Sample 2















Sample 3















Sample 4















Sample 5



















































after performing the analysis (MRT) I asked for the summary but I didn't get the surrogate splits, only the information for the primary splits (the secuence of commands I used is pasted at the end of the email). I would like to know how to get the information about the surrogate splits, please let me know any ideas.

Thank you very much in advanced,

Looking forward to hearing from you,



Dr. Carolina Trochine
Centro Regional Universitario Bariloche
Unidad Postal Universidad.
R8400FRF. Bariloche, Argentina
e-mail:trochine@crub.uncoma.edu.ar
http://investigadores.uncoma.edu.ar/Lab_Limnologia/default.htm



Here is the sequence of commands I used 



sprot_matrix=read.csv("sprot_matrix.csv", row.names=1)

sprot_matrix





require(mvpart)





mrtsprot_matrix <-

mvpart(data.matrix(sprot_matrix [,1:47]) ~SECCHI+PH+TA+PTOT+NTOT+CHLA+AREA+ MEANDEP, sprot_matrix,xv="pick",xvmult=500,use.n=TRUE,all=TRUE,text.add=TRUE)


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