Hi, 

I'm relative new to R and ROPLS so please forgive any errors in this message.

I am trying to perform a PLS-DA analysis using the ROPLS package on some NMR data in an R object 'sunoesy' (less the first four columns which contain non-numeric data). The y response is a categorical factor 'treatment'. After running the code I get the following error message:

sunoesy.lpsda<-opls(sunoesy[,-c(1:4)], treatment)
Error in if (ncol(ynMN) == 1 || drop(sqrt(crossprod((tOldVn - tVn)/tVn))) <  : 
  missing value where TRUE/FALSE needed

I have been through my data object 'sunoesy' and there are no missing values or NAs. I suspect that the kind of error described here might be occurring (https://stackoverflow.com/questions/20541883/weird-error-in-r), but I don't know how to go about sorting this out given I am using pre-defined code within an r package.

Many thanks for any assistance.

Abigail x

Hi Abigail,

Did you check that there is any variable with constant value for all samples in your dataset?

Otherwise, could you share your "sunoesy" data with me (etienne.thevenot@cea.fr)?

Best wishes,

Etienne.

Dear Etienne,

I don't think there are any variables with constant values. I have sent you the data over so you can assess. Thanks so much for your help.

Abigail

Hi Abigail,

I ran the script below on your data (PCA and PLS-DA) without any error.

The modeling with PLS-DA does not appear significant (pQ2 = 0.1). In addition, since you have 1e3 times more variables than samples, the risk of overfitting is very high.

Best wishes,

Etienne.

sunDF <- read.table("sunoesy.csv",
                    header = TRUE,
                    sep = ",",
                    stringsAsFactors = FALSE)
library(ropls)
strF(sunDF)

datMN <- as.matrix(sunDF[, -c(1:5)])
samDF <- sunDF[, 3:5]
rownames(samDF) <- rownames(datMN) <- sunDF[, "X"]

## PCA

pcaMod <- opls(datMN, predI = 2)
plot(pcaMod, parAsColFcVn = samDF[, "Treatment"])

## PLS-DA

opls(datMN, samDF[, "Treatment"], predI = 2)

Dear Etienne,

Thank you very much for your help with this. I have run the code you suggested and it works for me too. I think I may have made a relatively simply error to do with including an extra column of metadata in the columns used for PLS. My apologies, and thanks for your help.

Abigail