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#' Are two vertices adjacent?
#'
#' @description
#' `r lifecycle::badge("deprecated")`
#'
#' `are.connected()` was renamed to `are_adjacent()` to create a more
#' consistent API.
#' @inheritParams are_adjacent
#' @keywords internal
#' @export
are.connected <- function(graph, v1, v2) { # nocov start
lifecycle::deprecate_soft("2.0.0", "are.connected()", "are_adjacent()")
are_adjacent(graph = graph, v1 = v1, v2 = v2)
} # nocov end
# IGraph R package
# Copyright (C) 2005-2012 Gabor Csardi <csardi.gabor@gmail.com>
# 334 Harvard street, Cambridge, MA 02139 USA
#
# 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
# (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, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301 USA
#
###################################################################
#' Are two vertices adjacent?
#'
#' The order of the vertices only matters in directed graphs,
#' where the existence of a directed `(v1, v2)` edge is queried.
#'
#' @param graph The graph.
#' @param v1 The first vertex, tail in directed graphs.
#' @param v2 The second vertex, head in directed graphs.
#' @return A logical scalar, `TRUE` if edge `(v1, v2)` exists in the graph.
#'
#' @family structural queries
#'
#' @export
#' @examples
#' ug <- make_ring(10)
#' ug
#' are_adjacent(ug, 1, 2)
#' are_adjacent(ug, 2, 1)
#'
#' dg <- make_ring(10, directed = TRUE)
#' dg
#' are_adjacent(ug, 1, 2)
#' are_adjacent(ug, 2, 1)
#' @cdocs igraph_are_adjacent
are_adjacent <- are_adjacent_impl
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