diss_cosine: Cosine dissimilarity method constructor

In resemble: Similarity Retrieval and Local Learning for Spectral Chemometrics

Cosine dissimilarity method constructor

Description

Creates a configuration object for computing cosine dissimilarity (also known as spectral angle mapper). Pass the result to dissimilarity() to compute the dissimilarity matrix.

The cosine dissimilarity between two observations x_i and x_j is:

c(x_i, x_j) = \cos^{-1} \frac{\sum_{k=1}^{p} x_{i,k}\, x_{j,k}} {\sqrt{\sum_{k=1}^{p} x_{i,k}^{2}}\, \sqrt{\sum_{k=1}^{p} x_{j,k}^{2}}}

where p is the number of variables.

Usage

diss_cosine(center = TRUE, scale = FALSE)

Arguments

center	Logical. Center the data before computing dissimilarities? Applied jointly to Xr and Xu if both are provided. Default TRUE.
scale	Logical. Scale the data before computing dissimilarities? Applied jointly to Xr and Xu if both are provided. Default FALSE.

Value

An object of class c("diss_cosine", "diss_method").

Author(s)

Leonardo Ramirez-Lopez

See Also

dissimilarity, diss_euclidean, diss_mahalanobis

Examples

m <- diss_cosine()
m <- diss_cosine(center = FALSE)

resemble documentation built on April 21, 2026, 1:07 a.m.