A matrix with the available compositional data, but zeros are not allowed.
x
A matrix with the continuous predictor variables.
nfolds
The number of folds to use.
folds
If you have the list with the folds supply it here.
seed
You can specify your own seed number here or leave it NULL.
nterms
The number of terms to try in the projection pursuit regression.
type
Either "alr" or "ilr" corresponding to the additive or the isometric log-ratio transformation respectively.
yb
If you have already transformed the data using a log-ratio transformation put it here.
Othewrise leave it NULL.
Value
A list including:
kl
The average Kullback-Leibler divergence.
perf
The average Kullback-Leibler divergence.
runtime
The run time of the cross-validation procedure.
Details
The function performs tuning of the projection pursuit regression algorithm.
References
Friedman, J. H. and Stuetzle, W. (1981). Projection pursuit regression. Journal of the American
Statistical Association, 76, 817-823. doi: 10.2307/2287576.