graph/path/internal: add more negative cycle cases
MODIFY
graph/path/internal/testgraphs/shortest.go
graph/path/internal/testgraphs/shortest.go
@@ -596,6 +596,56 @@ var ShortestPathTests = []struct {
Query: simple.Edge{F: simple.Node(0), T: simple.Node(1)},
},
+ {
+ Name: "two path directed negative cycle",
+ Graph: func() graph.WeightedEdgeAdder { return simple.NewWeightedDirectedGraph(0, math.Inf(1)) },
+ Edges: []simple.WeightedEdge{
+ {F: simple.Node(0), T: simple.Node(1), W: 1},
+ {F: simple.Node(1), T: simple.Node(2), W: -1},
+ {F: simple.Node(2), T: simple.Node(1), W: -1},
+ {F: simple.Node(1), T: simple.Node(3), W: 1},
+ {F: simple.Node(0), T: simple.Node(4), W: 1},
+ },
+ HasNegativeWeight: true,
+ HasNegativeCycle: true,
+
+ Query: simple.Edge{F: simple.Node(0), T: simple.Node(3)},
+ },
+ {
+ Name: "two path directed off-path negative cycle",
+ Graph: func() graph.WeightedEdgeAdder { return simple.NewWeightedDirectedGraph(0, math.Inf(1)) },
+ Edges: []simple.WeightedEdge{
+ {F: simple.Node(0), T: simple.Node(1), W: 1},
+ {F: simple.Node(1), T: simple.Node(2), W: -1},
+ {F: simple.Node(2), T: simple.Node(1), W: -1},
+ {F: simple.Node(1), T: simple.Node(3), W: 1},
+ {F: simple.Node(0), T: simple.Node(4), W: 10}, // Push search into negative cycle.
+ },
+ HasNegativeWeight: true,
+ HasNegativeCycle: true,
+
+ Query: simple.Edge{F: simple.Node(0), T: simple.Node(4)},
+ Weight: 10,
+ WantPaths: [][]int64{
+ {0, 4},
+ },
+ HasUniquePath: true,
+ },
+ {
+ Name: "two path directed diamond negative cycle",
+ Graph: func() graph.WeightedEdgeAdder { return simple.NewWeightedDirectedGraph(0, math.Inf(1)) },
+ Edges: []simple.WeightedEdge{
+ {F: simple.Node(0), T: simple.Node(1), W: 1},
+ {F: simple.Node(1), T: simple.Node(2), W: -1},
+ {F: simple.Node(2), T: simple.Node(1), W: -1},
+ {F: simple.Node(1), T: simple.Node(3), W: 1},
+ {F: simple.Node(0), T: simple.Node(3), W: 10}, // Push search into negative cycle.
+ },
+ HasNegativeWeight: true,
+ HasNegativeCycle: true,
+
+ Query: simple.Edge{F: simple.Node(0), T: simple.Node(3)},
+ },
{
Name: "wp graph negative", // http://en.wikipedia.org/w/index.php?title=Johnson%27s_algorithm&oldid=564595231
Graph: func() graph.WeightedEdgeAdder { return simple.NewWeightedDirectedGraph(0, math.Inf(1)) },

graph/path/internal: add more negative cycle cases