[R] "mvr" function

[McGehee, Robert]

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:j_brindle at hotmail.com] 
Sent: Wednesday, June 01, 2005 5:03 PM
To: r-help at stat.math.ethz.ch
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

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