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Similarity index for LW-PLS

Source: R/similarity.R
similarity.Rd

The similarity index determines how the distance between a query sample and the training samples is measured before it is turned into weights by lwpls():

Usage

similarity(values = values_similarity)

values_similarity

Arguments

values

A character vector of possible similarity indexes.

Value

A qual_param object (see dials::new_qual_param()).

Details

  • "euclidean": the Euclidean distance between the (standardized) predictors, as in the original LW-PLS.

  • "covariance": the distance after projecting the samples on the covariance direction \(\Gamma = X^\top Y / \lVert X^\top Y \rVert\) (covariance-based LW-PLS, CbLW-PLS; Hazama and Kano, 2015). It accounts for the relationships among the predictors and between the predictors and the outcome(s).

See vignette("similarity") for how to choose between them.

References

Hazama, K. and Kano, M. (2015). Covariance-based locally weighted partial least squares for high-performance adaptive modeling. Chemometrics and Intelligent Laboratory Systems, 146, 55–62. doi:10.1016/j.chemolab.2015.05.007

Examples

similarity()
#> Similarity Index (qualitative)
#> 2 possible values include:
#> 'euclidean' and 'covariance'
values_similarity
#> [1] "euclidean"  "covariance"