From 6404c76aac0c949d11b3c00c1a13f869e781abed Mon Sep 17 00:00:00 2001
From: joeroe <jroeuk@gmail.com>
Date: Sat, 29 Dec 2018 19:06:52 +0100
Subject: [PATCH] Add basic validation as suggested by tsdye (#1)

---
 R/graph.R              | 21 +++++++++++++++++++++
 man/is_valid_harris.Rd | 19 +++++++++++++++++++
 2 files changed, 40 insertions(+)
 create mode 100644 man/is_valid_harris.Rd

diff --git a/R/graph.R b/R/graph.R
index 737dcf5..739b41b 100644
--- a/R/graph.R
+++ b/R/graph.R
@@ -23,4 +23,25 @@ harris <- function(data, context, relation) {
   tibble::tibble(to, from) %>%
     drop_na() %>%
     return()
+}
+
+#' Validate stratigraphic graphs
+#'
+#' Checks whether a stratigraphic graph is a valid Harris matrix.
+#'
+#' @param stratgraph  A stratigraphic graph.
+#' @param warn        Display warnings for invalid graphs (Default: `TRUE`).
+#'
+#' @return `TRUE` or `FALSE`
+#' @export
+#'
+#' @examples
+is_valid_harris <- function(stratgraph, warn = TRUE) {
+  if (!igraph::is.dag(stratgraph)) {
+    if(warn) warning("Invalid Harris matrix: graph contains cycles")
+    return(FALSE)
+  }
+  else {
+    return(TRUE)
+  }
 }
\ No newline at end of file
diff --git a/man/is_valid_harris.Rd b/man/is_valid_harris.Rd
new file mode 100644
index 0000000..8746f7d
--- /dev/null
+++ b/man/is_valid_harris.Rd
@@ -0,0 +1,19 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/graph.R
+\name{is_valid_harris}
+\alias{is_valid_harris}
+\title{Validate stratigraphc graphs}
+\usage{
+is_valid_harris(stratgraph, warn = TRUE)
+}
+\arguments{
+\item{stratgraph}{A stratigraphic graph.}
+
+\item{warn}{Display warnings for invalid graphs (Default: `TRUE`).}
+}
+\value{
+`TRUE` or `FALSE`
+}
+\description{
+Checks whether a stratigraphic graph is a valid Harris matrix.
+}