Add implemention of multi-edge-networks for author and artifact networks

Now, it is possible to construct networks which include more than one
artifact and author relation.

To provide this functionality, the allowed number of the
'author.relation' and the 'artifact.relation'
is changed to Inf instead of 1.
A further edge attribute 'relation' is added to describe the relation
type. The functions 'get.artifact.network' and 'get.author.network' are
changed to handle more than one relation. Therefore, the functions
'get.bipartite.network' and 'get.multi.network' are adjusted, too. The
functions use the 'add.edges.for.bipartite.relations' function which can
handle more than one relation now.
To merge the networks of all relations, we add the functions
'merge.network.data' and 'merge.networks'. The function
'construct.network.from.list' is split into to functions
'construct.edge.list.from.key.value.list' and
'construct.network.from.edge.list'.

Solves the second part of se-sic#98.

Signed-off-by: Barbara Eckl <[email protected]>
Signed-off-by: Claus Hunsen <[email protected]>

tests/test-networks-artifact.R

@@ -57,6 +57,7 @@ test_that("Network construction of the undirected artifact-cochange network", {
                       artifact.type = c("Feature", "Feature"),
                       artifact = c("Base_Feature", "foo"),
                       weight = c(1, 1),
+                      relation = c("cochange", "cochange"),
                       type = TYPE.EDGES.INTRA)
 
     ## build expected network

tests/test-networks-author.R

@@ -222,7 +222,8 @@ test_that("Network construction of the undirected author-cochange network", {
                       artifact.type = c("Feature", "Feature", "Feature", "Feature", "Feature", "Feature", "Feature", "Feature"),
                       artifact = c("A", "A", "Base_Feature", "Base_Feature", "Base_Feature", "Base_Feature", "Base_Feature", "Base_Feature"),
                       weight = c(1, 1, 1, 1, 1, 1, 1, 1),
-                      type = TYPE.EDGES.INTRA
+                      type = TYPE.EDGES.INTRA,
+                      relation = c("cochange", "cochange", "cochange", "cochange", "cochange", "cochange", "cochange", "cochange")
     )
 
     ## build expected network
@@ -262,7 +263,8 @@ test_that("Network construction of the directed author-cochange network", {
                       artifact.type = c("Feature", "Feature", "Feature", "Feature"),
                       artifact = c("A", "Base_Feature", "Base_Feature", "Base_Feature"),
                       weight = c(1, 1, 1, 1),
-                      type = TYPE.EDGES.INTRA
+                      type = TYPE.EDGES.INTRA,
+                      relation = c("cochange", "cochange", "cochange", "cochange")
     )
 
     ## build expected network
@@ -302,7 +304,8 @@ test_that("Network construction of the undirected simplified author-cochange net
                       artifact.type = I(list(c("Feature", "Feature"), c("Feature", "Feature"), c("Feature", "Feature"), c("Feature", "Feature"))),
                       artifact = I(list(c("A", "A"), c("Base_Feature", "Base_Feature"), c("Base_Feature", "Base_Feature"), c("Base_Feature", "Base_Feature"))),
                       weight = c(2, 2, 2, 2),
-                      type = TYPE.EDGES.INTRA
+                      type = TYPE.EDGES.INTRA,
+                      relation = c("cochange", "cochange", "cochange", "cochange")
     )
 
     ## build expected network
@@ -399,7 +402,17 @@ test_that("Network construction of the undirected author-issue network with all
                                    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
                                    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
                                    1, 1, 1, 1 ),
-                       type = TYPE.EDGES.INTRA)
+                       type = TYPE.EDGES.INTRA,
+                       relation = c("issue", "issue", "issue", "issue", "issue", "issue", "issue", "issue", "issue",
+                                     "issue", "issue", "issue", "issue", "issue", "issue", "issue", "issue", "issue",
+                                     "issue", "issue", "issue", "issue", "issue", "issue", "issue", "issue", "issue",
+                                     "issue", "issue", "issue", "issue", "issue", "issue", "issue", "issue", "issue",
+                                     "issue", "issue", "issue", "issue", "issue", "issue", "issue", "issue", "issue",
+                                     "issue", "issue", "issue", "issue", "issue", "issue", "issue", "issue", "issue",
+                                     "issue", "issue", "issue", "issue", "issue", "issue", "issue", "issue", "issue",
+                                     "issue", "issue", "issue", "issue", "issue", "issue", "issue", "issue", "issue",
+                                     "issue", "issue", "issue", "issue")
+            )
 
     network.expected = igraph::graph.data.frame(edges, directed = FALSE, vertices = vertices)
 
@@ -442,7 +455,8 @@ test_that("Network construction of the undirected author-issue network with just
                                        "commented", "commented", "commented", "commented", "commented", "commented",
                                        "commented", "commented", "commented", "commented", "commented", "commented" ),
                        weight = c(1),
-                       type = TYPE.EDGES.INTRA)
+                       type = TYPE.EDGES.INTRA,
+                       relation = c("issue"))
 
     network.expected = igraph::graph.data.frame(edges, directed = FALSE, vertices = vertices)