Plot of weights

Plots the weights of X variables from a PLS regression.

plo_ctr(object, comp = 1, sort = FALSE, col = "tomato4", repel = FALSE)

Arguments

object

an object of class mvr from pls package

comp

the component to use. Default is 1.

sort

logical. If TRUE, bars are sorted by decreasing VIPs. Default is FALSE.

col

color of the bars

repel

logical. If TRUE, the names of the variables are repelled with geom_text_repel. Default is FALSE

Value

a ggplot2 object

Details

According to Tenenhaus, the contribution of a variable to the construction of a component is measured by the squared loading weight. For a given component, the sum af the squared loading weights is equal to 1. This plot represents the loading weights, which keeps the information about their sign. Dashed lines are added at +/- sqrt(1/p), with p the number of X variables, which corresponds to the average contribution to the construction of the component.

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

See also

plo_coef, plo_vip

Examples

library(pls)
data(yarn)
pls <- mvr(density ~ NIR,
           ncomp = 5,
           data = yarn,
           validation = "CV",
           method = "oscorespls")
plo_ctr(pls)