DIABLO of Fold Change data

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1

Hello mixOmics team,

I have been trying to use the DIABLO model to integrate RNAseq data and Metabolomics data of different plants in response to a virus. Since I am interested only in the differences in response to the virus, I want to use fold change data as input in the model (i.e. the ratio between inoculated and non-inoculated plants). I managed to make DIABLO work using the raw fold change ratio (inoc/mock) but when I try to use the log2(Fold Change) in order to make the data symetrical, I get stuck at the tuning step. I get this error:

tune.diablo = tune.block.splsda(X = data, Y = Y, ncomp = ncomp, 
                                 test.keepX = test.keepX, design = design,
                                 validation = 'loo', folds = 10, nrepeat = 1,
                                 dist = "max.dist")
Error in 1:n : Argument is NA / NaN

Is it because the Log2 transformation introduces negative values?

Also I read that one would have to use a high number of repeats (at least 100) in order to tune the model correctly. Is that the case with LOO cross validation?

Thank you in advance for your help,

Julien