R/DSD_UniformNoise.R

In mhahsler/stream: Infrastructure for Data Stream Mining

#######################################################################
# stream -  Infrastructure for Data Stream Mining
# Copyright (C) 2013 Michael Hahsler, Matthew Bolanos, John Forrest
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.


#' Uniform Noise Data Stream Generator
#'
#' This generator produces uniform noise in a d-dimensional unit (hyper) cube.
#'
#' @family DSD
#'
#' @param d Determines the number of dimensions.
#' @param range A matrix with two columns and `d` rows giving the minimum
#' and maximum for each dimension. Defaults to the range of \eqn{[0,1]}.
#' @return Returns a `DSD_UniformNoise` object.(subclass of `DSD_R`,
#' `DSD`).
#' @author Michael Hahsler
#' @examples
#' # create data stream with three clusters in 2D
#' stream <- DSD_UniformNoise(d = 2)
#' get_points(stream, n = 5)
#' plot(stream, n = 100)
#'
#' # specify a different range for each dimension
#' stream <- DSD_UniformNoise(d = 3,
#'   range = rbind(c(0, 1), c(0, 10), c(0, 5)))
#' plot(stream, n = 100)
#' @export
DSD_UniformNoise <- function(d = 2, range = NULL) {
  if (is.null(range))
    range <- matrix(c(0, 1),
      ncol = 2,
      nrow = d,
      byrow = TRUE)
  structure(
    list(
      description = paste0("Uniform Noise (d = ", d, ")"),
      d = d,
      range = range
    ),
    class = c("DSD_UniformNoise", "DSD_R", "DSD")
  )
}

#' @export
get_points.DSD_UniformNoise <- function(x,
  n = 1L,
  info = TRUE,
  ...) {
  .nodots(...)

  if (n < 0L)
    stop("n < 0 not allowed for infinite data stream objects.")

  if (n == 0) {
    data <-
      as.data.frame(matrix(
        nrow = 0,
        ncol = x$d,
        dimnames = list(row = NULL, col = paste0("X", 1:x$d))
      ))

    if (info)
      data[[".class"]] <- integer(0)

    return(data)
  }

  data <- t(replicate(n,
    runif(
      x$d, min = x$range[, 1], max = x$range[, 2]
    )))

  ### handle 1-d case
  if (x$d == 1)
    data <- t(data)

  data <- data.frame(data)
  colnames(data) <- paste0("X", 1:ncol(data))

  if (info)
    data[[".class"]] <- NA

  data
}