subsampling functions

R/subsampling.R

@@ -0,0 +1,96 @@
+#' Subsampling
+
+#' @description Subsample by a greedy strategy of iteratively adding the
+#'   farthest point from the current chosen point set to the subsampling. The
+#'   iteration starts with the landmark starting point.
+#'
+#' @author Vincent Rouvreau, Marc Glisse, Masatoshi Takenouchi
+#'
+#' @param points (Iterable[Iterable[float]]) – The input point set.
+#'
+#' Or
+#' 
+#' @param off_file (string) – An OFF file style name.
+#'
+#' And in both cases
+#' 
+#' @param nb_points (int) – Number of points of the subsample (the subsample
+#'   may be smaller if there are fewer than `nb_points` distinct input points).
+#'   Default: all of them.
+#' @param starting_point (int) – The iteration starts with the landmark
+#'   starting point, which is the index of the point to start with. If not set,
+#'   this index is chosen randomly.
+#' @param fast (bool) – If True (default), use an implementation that is
+#'   efficient when the doubling dimension and spread are small, but slow
+#'   otherwise. If False, use the standard quadratic algorithm.
+#'
+#' @return The subsample point set, in the order they were selected by the 
+#'   greedy strategy.
+#' @export
+choose_n_farthest_points <- function(points = NULL,
+                                     off_file = "",
+                                     nb_points = 18446744073709551615,
+                                     starting_point = NULL,
+                                     fast = TRUE) {
+  gd$subsampling$choose_n_farthest_points(
+    points = points,
+    off_file = off_file,
+    nb_points = nb_points,
+    starting_point = starting_point,
+    fast = fast
+  )
+}
+
+#' @description Subsample a point set by picking random vertices.
+#'
+#' @author Vincent Rouvreau, Marc Glisse, Masatoshi Takenouchi
+#'
+#' @param points (Iterable[Iterable[float]]) – The input point set.
+#'
+#' Or
+#' 
+#' @param off_file (string) – An OFF file style name.
+#'
+#' And in both cases
+#' 
+#' @param nb_points (int) – Number of points of the subsample.
+#'
+#' @return The subsample point set.
+#' @export
+pick_n_random_points <- function(points = NULL,
+                                 off_file = "",
+                                 nb_points = 0) {
+  gd$subsampling$pick_n_random_points(
+    points = points,
+    off_file = off_file,
+    nb_points = nb_points
+  )
+}
+
+#' @description Outputs a subset of the input points so that the squared
+#'   distance between any two points is greater than `min_squared_dist`.
+#'
+#' @author Vincent Rouvreau, Marc Glisse, Masatoshi Takenouchi
+#'
+#' @param points (Iterable[Iterable[float]]) – The input point set.
+#'
+#' Or
+#' 
+#' @param off_file (string) – An OFF file style name.
+#'
+#' And in both cases
+#' 
+#' @param min_squared_dist (float) – Minimum squared distance separating the
+#'   output points.
+#'
+#' @return The subsample point set.
+#' @export
+sparsify_point_set <- function(points = NULL,
+                               off_file = "",
+                               min_squared_dist = 0.0) {
+  gd$subsampling$sparsify_point_set(
+    points = points,
+    off_file = off_file,
+    min_squared_dist = min_squared_dist
+  )
+}

_pkgdown.yml

@@ -87,3 +87,8 @@ reference:
     - fetch_bunny
     - fetch_spiral_2d
     - clear_data_home
+  - title: Subsampling
+  - contents:
+    - choose_n_farthest_points
+    - pick_n_random_points
+    - sparsify_point_set