R/umap_small.R

In umap: Uniform Manifold Approximation and Projection

# package umap
# functions to produce umap objects for extremely small datasets
# i.e. datasets with 0, 1, or 2 items

#' Create an embedding object compatible for very small inputs
#'
#' @keywords internal
#' @noRd
#' @param d matrix
#' @param config list with settings
#'
#' @return list, one element of which is matrix with embedding coordinates
umap.small <- function(d, config) {
  
  warning("constructing layout for a very small input dataset", call.=FALSE)

  embedding <- matrix(0, ncol=config$n_components, nrow=nrow(d))
  if (nrow(d) == 2) {
    embedding[1,] <- 5
    embedding[2,] <- -5
  }
  rownames(embedding) <- rownames(d)
  
  list(layout=embedding, config=config)
}