Dependency graphs

Dependency graphs

Dependency graphs is a module that can be used to analyze dependencies between graphs. The graphs can have positive or negative edges.

In the following declaration g1 is a graph with three nodes a, b and c, and a positive edge between a and b and a negative edge between a and c.

import es.weso.depgraphs._

val g1 = DepGraph.empty[String].
        addPosEdge("a", "b").
        addNegEdge("a", "c")
// g1: DepGraph[String] = DepGraphJGraphT()

An important operation is to detect if there are negative cycles in a dependency graph. g1 doesn't contain negative cycles.

g1.containsNegCycle
// res0: Boolean = false

On the other hand, the following graph contains negative cycles.

val g = DepGraph.empty[String].
        addNegEdge("a", "b").
        addPosEdge("a", "c").
        addPosEdge("b", "d").
        addPosEdge("d", "a")
// g: DepGraph[String] = DepGraphJGraphT()

g.containsNegCycle
// res1: Boolean = true

negCycles returns the cycles with negative dependencies.

g.negCycles
// res2: Set[Set[(String, String)]] = Set(
//   Set(("a", "b"), ("b", "d"), ("d", "a"))
// )