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").
Examples
m <- diss_cosine()
m <- diss_cosine(center = FALSE)
