BuchheimWalkerLayoutManager crashes if a node has two parents

[NewColours]

The first walk tries to figure out layout size by looking at prelim sibling. Since the sibling is itself due to having edges from two parents, it crashes with NoSuchElementException

This seems like it should be a valid use (for something like an elimination tournament) although not a true tree in the datastructure sense

at kotlin.collections.MapsKt__MapWithDefaultKt.getOrImplicitDefaultNullable(MapWithDefault.kt:24)
at kotlin.collections.MapsKt__MapsKt.getValue(Maps.kt:344)
at dev.bandb.graphview.layouts.tree.BuchheimWalkerLayoutManager.getNodeData(BuchheimWalkerLayoutManager.kt:40)
at dev.bandb.graphview.layouts.tree.BuchheimWalkerLayoutManager.executeShifts(BuchheimWalkerLayoutManager.kt:128)
at dev.bandb.graphview.layouts.tree.BuchheimWalkerLayoutManager.firstWalk(BuchheimWalkerLayoutManager.kt:73)
at dev.bandb.graphview.layouts.tree.BuchheimWalkerLayoutManager.firstWalk(BuchheimWalkerLayoutManager.kt:67)
at dev.bandb.graphview.layouts.tree.BuchheimWalkerLayoutManager.firstWalk(BuchheimWalkerLayoutManager.kt:67)
at dev.bandb.graphview.layouts.tree.BuchheimWalkerLayoutManager.run(BuchheimWalkerLayoutManager.kt:330)

[DennisBlock]

The BuchheimWalker algorithm is unfortunately only for trees and therefore can only handle one parent. You could try the Sugiyama algorithm, which accepts multiple parents. But maybe the layout will not look as nice then. You have to see if this is enough for your purposes. Otherwise the only way is to develop another/your own algorithm.

[GregorBlock]

I'm closing this issue due to inactivity. If you have further input on the issue, don't hesitate to reopen this issue or post a new one.