R/which_antichain.R

In nuggets: Extensible Framework for Data Pattern Exploration

#######################################################################
# nuggets: An R framework for exploration of patterns in data
# Copyright (C) 2025 Michal Burda
#
# 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 3 of the License, or
# (at your option) 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, see <https://www.gnu.org/licenses/>.
#######################################################################


#' Return indices of first elements of the list, which are incomparable with preceding
#' elements.
#'
#' The function returns indices of elements from the given list `x`, which are incomparable
#' (i.e., it is neither subset nor superset) with any preceding element. The first element
#' is always selected. The next element is selected only if it is incomparable with all
#' previously selected elements.
#'
#' @param x a list of integerish vectors
#' @param distance a non-negative integer, which specifies the allowed discrepancy between compared sets
#' @return an integer vector of indices of selected (incomparable) elements.
#' @author Michal Burda
#' @export
which_antichain <- function(x, distance = 0) {
    .must_be_list_of_integerishes(x)
    .must_be_integerish_scalar(distance)
    .must_be_greater_eq(distance, 0)

    x <- lapply(x, as.integer)

    which_antichain_(x, as.integer(distance))
}