Q2 and cumulative Q2 indexes

Computes Q2 and cumulative Q2 indexes from a PLS regression.

get_Q2(object)

Arguments

object

an object of class mvr from pls package. It has to be cross-validated

Value

A list with the following elements :

Q2kh

Q2 index by X variable and number of components

Q2h

Q2 index by number of components

Q2cumkh

cumulative Q2 index by X variable and number of components

Q2cumh

cumulative Q2 index by number of components

References

Martens, H., Næs, T. (1989) Multivariate calibration. Chichester: Wiley.

Tenenhaus, M. (1998) La Regression PLS. Theorie et Pratique. Editions TECHNIP, Paris.

Author

Nicolas Robette

Examples

library(pls)
#> 
#> Attaching package: ‘pls’
#> The following object is masked from ‘package:stats’:
#> 
#>     loadings
data(yarn)
pls <- mvr(density ~ NIR,
           ncomp = 5,
           data = yarn,
           validation = "CV",
           method = "oscorespls")
res <- get_Q2(pls)
str(res)
#> List of 4
#>  $ Q2kh   : num [1, 1:5] 0.961 -0.367 0.655 0.749 -0.564
#>   ..- attr(*, "dimnames")=List of 2
#>   .. ..$ : chr "density"
#>   .. ..$ : chr [1:5] "1 comps" "2 comps" "3 comps" "4 comps" ...
#>  $ Q2h    : Named num [1:5] 0.961 -0.367 0.655 0.749 -0.564
#>   ..- attr(*, "names")= chr [1:5] "1 comps" "2 comps" "3 comps" "4 comps" ...
#>  $ Q2cumkh: num [1, 1:5] 0.961 0.947 0.982 0.995 0.993
#>   ..- attr(*, "dimnames")=List of 2
#>   .. ..$ : chr "density"
#>   .. ..$ : chr [1:5] "1 comps" "2 comps" "3 comps" "4 comps" ...
#>  $ Q2cumh : Named num [1:5] 0.961 0.947 0.982 0.995 0.993
#>   ..- attr(*, "names")= chr [1:5] "1 comps" "2 comps" "3 comps" "4 comps" ...