Jim, I had some of the same difficulties. The NIR data frame consists of a column of y variables and a matrix of X variables (and until looking at this dataset, I had not realized that data frames could hold matrices). So, after consulting the R-help sages, I turned by data into an identical structure using something like this:
dataSet <- data.frame(y = vol[, 12]) dataSet$X <- data.matrix(vol[, 1:11]) ans.pcr <- pcr(y ~ X, 6, data = dataSet, validation = "CV") If there's a more elegant way of doing this without using data frames of matrices, I'd be interested as well. HTH, Robert -----Original Message----- From: Jim BRINDLE [mailto:[EMAIL PROTECTED] Sent: Wednesday, June 01, 2005 5:03 PM To: [email protected] Subject: [R] "mvr" function Hello, I am trying to understand how to utilize the "mvr" function in the pls Package of R. I am utilizing the R "pls Package" document dated 18 May 2005 as guidance. My data set consists of a 12 x 12 data frame created from reading in a table of values. I have read the data in via the command: volumes <- read.table("THA_vol.txt", header = TRUE) and then created a data.frame called "vol". My response variable is in the last column of the "vol" data frame and my dependent variables are in columns 1 through 11. To familiarize myself with this approach I have utilized the NIR data set (included in the pls Package). I get the following command to work with the NIR data set: NIR.pcr <- pcr(y ~ X,6,data=NIR,validation="CV") However, when I run the following script which effectively substitutes my data set (& modify variable names accordingly) into the above equation: y <- vol[,12] X <- vol[,1:11] ans.pcr <- pcr(y ~ X,6,data=vol,validation="CV") I get the following error: Error in model.frame(formula, rownames, variables, varnames, extras, extranames, : invalid variable type I have looked at the NIR data set in the pls Package and tried to see how it "structurally" differs from my data-set "structure" (other than in its size). Does anyone have any insight they might be willing to share? Thank you kindly. - Jim ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
