diff env/lib/python3.9/site-packages/networkx/algorithms/shortest_paths/tests/test_dense.py @ 0:4f3585e2f14b draft default tip

"planemo upload commit 60cee0fc7c0cda8592644e1aad72851dec82c959"

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/env/lib/python3.9/site-packages/networkx/algorithms/shortest_paths/tests/test_dense.py	Mon Mar 22 18:12:50 2021 +0000
@@ -0,0 +1,211 @@
+import pytest
+import networkx as nx
+
+
+class TestFloyd:
+    @classmethod
+    def setup_class(cls):
+        pass
+
+    def test_floyd_warshall_predecessor_and_distance(self):
+        XG = nx.DiGraph()
+        XG.add_weighted_edges_from(
+            [
+                ("s", "u", 10),
+                ("s", "x", 5),
+                ("u", "v", 1),
+                ("u", "x", 2),
+                ("v", "y", 1),
+                ("x", "u", 3),
+                ("x", "v", 5),
+                ("x", "y", 2),
+                ("y", "s", 7),
+                ("y", "v", 6),
+            ]
+        )
+        path, dist = nx.floyd_warshall_predecessor_and_distance(XG)
+        assert dist["s"]["v"] == 9
+        assert path["s"]["v"] == "u"
+        assert dist == {
+            "y": {"y": 0, "x": 12, "s": 7, "u": 15, "v": 6},
+            "x": {"y": 2, "x": 0, "s": 9, "u": 3, "v": 4},
+            "s": {"y": 7, "x": 5, "s": 0, "u": 8, "v": 9},
+            "u": {"y": 2, "x": 2, "s": 9, "u": 0, "v": 1},
+            "v": {"y": 1, "x": 13, "s": 8, "u": 16, "v": 0},
+        }
+
+        GG = XG.to_undirected()
+        # make sure we get lower weight
+        # to_undirected might choose either edge with weight 2 or weight 3
+        GG["u"]["x"]["weight"] = 2
+        path, dist = nx.floyd_warshall_predecessor_and_distance(GG)
+        assert dist["s"]["v"] == 8
+        # skip this test, could be alternate path s-u-v
+        #        assert_equal(path['s']['v'],'y')
+
+        G = nx.DiGraph()  # no weights
+        G.add_edges_from(
+            [
+                ("s", "u"),
+                ("s", "x"),
+                ("u", "v"),
+                ("u", "x"),
+                ("v", "y"),
+                ("x", "u"),
+                ("x", "v"),
+                ("x", "y"),
+                ("y", "s"),
+                ("y", "v"),
+            ]
+        )
+        path, dist = nx.floyd_warshall_predecessor_and_distance(G)
+        assert dist["s"]["v"] == 2
+        # skip this test, could be alternate path s-u-v
+        # assert_equal(path['s']['v'],'x')
+
+        # alternate interface
+        dist = nx.floyd_warshall(G)
+        assert dist["s"]["v"] == 2
+
+        # floyd_warshall_predecessor_and_distance returns
+        # dicts-of-defautdicts
+        # make sure we don't get empty dictionary
+        XG = nx.DiGraph()
+        XG.add_weighted_edges_from(
+            [("v", "x", 5.0), ("y", "x", 5.0), ("v", "y", 6.0), ("x", "u", 2.0)]
+        )
+        path, dist = nx.floyd_warshall_predecessor_and_distance(XG)
+        inf = float("inf")
+        assert dist == {
+            "v": {"v": 0, "x": 5.0, "y": 6.0, "u": 7.0},
+            "x": {"x": 0, "u": 2.0, "v": inf, "y": inf},
+            "y": {"y": 0, "x": 5.0, "v": inf, "u": 7.0},
+            "u": {"u": 0, "v": inf, "x": inf, "y": inf},
+        }
+        assert path == {
+            "v": {"x": "v", "y": "v", "u": "x"},
+            "x": {"u": "x"},
+            "y": {"x": "y", "u": "x"},
+        }
+
+    def test_reconstruct_path(self):
+        with pytest.raises(KeyError):
+            XG = nx.DiGraph()
+            XG.add_weighted_edges_from(
+                [
+                    ("s", "u", 10),
+                    ("s", "x", 5),
+                    ("u", "v", 1),
+                    ("u", "x", 2),
+                    ("v", "y", 1),
+                    ("x", "u", 3),
+                    ("x", "v", 5),
+                    ("x", "y", 2),
+                    ("y", "s", 7),
+                    ("y", "v", 6),
+                ]
+            )
+            predecessors, _ = nx.floyd_warshall_predecessor_and_distance(XG)
+
+            path = nx.reconstruct_path("s", "v", predecessors)
+            assert path == ["s", "x", "u", "v"]
+
+            path = nx.reconstruct_path("s", "s", predecessors)
+            assert path == []
+
+            # this part raises the keyError
+            nx.reconstruct_path("1", "2", predecessors)
+
+    def test_cycle(self):
+        path, dist = nx.floyd_warshall_predecessor_and_distance(nx.cycle_graph(7))
+        assert dist[0][3] == 3
+        assert path[0][3] == 2
+        assert dist[0][4] == 3
+
+    def test_weighted(self):
+        XG3 = nx.Graph()
+        XG3.add_weighted_edges_from(
+            [[0, 1, 2], [1, 2, 12], [2, 3, 1], [3, 4, 5], [4, 5, 1], [5, 0, 10]]
+        )
+        path, dist = nx.floyd_warshall_predecessor_and_distance(XG3)
+        assert dist[0][3] == 15
+        assert path[0][3] == 2
+
+    def test_weighted2(self):
+        XG4 = nx.Graph()
+        XG4.add_weighted_edges_from(
+            [
+                [0, 1, 2],
+                [1, 2, 2],
+                [2, 3, 1],
+                [3, 4, 1],
+                [4, 5, 1],
+                [5, 6, 1],
+                [6, 7, 1],
+                [7, 0, 1],
+            ]
+        )
+        path, dist = nx.floyd_warshall_predecessor_and_distance(XG4)
+        assert dist[0][2] == 4
+        assert path[0][2] == 1
+
+    def test_weight_parameter(self):
+        XG4 = nx.Graph()
+        XG4.add_edges_from(
+            [
+                (0, 1, {"heavy": 2}),
+                (1, 2, {"heavy": 2}),
+                (2, 3, {"heavy": 1}),
+                (3, 4, {"heavy": 1}),
+                (4, 5, {"heavy": 1}),
+                (5, 6, {"heavy": 1}),
+                (6, 7, {"heavy": 1}),
+                (7, 0, {"heavy": 1}),
+            ]
+        )
+        path, dist = nx.floyd_warshall_predecessor_and_distance(XG4, weight="heavy")
+        assert dist[0][2] == 4
+        assert path[0][2] == 1
+
+    def test_zero_distance(self):
+        XG = nx.DiGraph()
+        XG.add_weighted_edges_from(
+            [
+                ("s", "u", 10),
+                ("s", "x", 5),
+                ("u", "v", 1),
+                ("u", "x", 2),
+                ("v", "y", 1),
+                ("x", "u", 3),
+                ("x", "v", 5),
+                ("x", "y", 2),
+                ("y", "s", 7),
+                ("y", "v", 6),
+            ]
+        )
+        path, dist = nx.floyd_warshall_predecessor_and_distance(XG)
+
+        for u in XG:
+            assert dist[u][u] == 0
+
+        GG = XG.to_undirected()
+        # make sure we get lower weight
+        # to_undirected might choose either edge with weight 2 or weight 3
+        GG["u"]["x"]["weight"] = 2
+        path, dist = nx.floyd_warshall_predecessor_and_distance(GG)
+
+        for u in GG:
+            dist[u][u] = 0
+
+    def test_zero_weight(self):
+        G = nx.DiGraph()
+        edges = [(1, 2, -2), (2, 3, -4), (1, 5, 1), (5, 4, 0), (4, 3, -5), (2, 5, -7)]
+        G.add_weighted_edges_from(edges)
+        dist = nx.floyd_warshall(G)
+        assert dist[1][3] == -14
+
+        G = nx.MultiDiGraph()
+        edges.append((2, 5, -7))
+        G.add_weighted_edges_from(edges)
+        dist = nx.floyd_warshall(G)
+        assert dist[1][3] == -14