graph: imported graph as a subtree

graph/topo/common_test.go

@@ -0,0 +1,47 @@
+// Copyright ©2015 The gonum Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package topo
+
+// batageljZaversnikGraph is the example graph from
+// figure 1 of http://arxiv.org/abs/cs/0310049v1
+var batageljZaversnikGraph = []intset{
+	0: nil,
+
+	1: linksTo(2, 3),
+	2: linksTo(4),
+	3: linksTo(4),
+	4: linksTo(5),
+	5: nil,
+
+	6:  linksTo(7, 8, 14),
+	7:  linksTo(8, 11, 12, 14),
+	8:  linksTo(14),
+	9:  linksTo(11),
+	10: linksTo(11),
+	11: linksTo(12),
+	12: linksTo(18),
+	13: linksTo(14, 15),
+	14: linksTo(15, 17),
+	15: linksTo(16, 17),
+	16: nil,
+	17: linksTo(18, 19, 20),
+	18: linksTo(19, 20),
+	19: linksTo(20),
+	20: nil,
+}
+
+// intset is an integer set.
+type intset map[int]struct{}
+
+func linksTo(i ...int) intset {
+	if len(i) == 0 {
+		return nil
+	}
+	s := make(intset)
+	for _, v := range i {
+		s[v] = struct{}{}
+	}
+	return s
+}