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  • LAYER_SWEEP
    The layer sweep algorithm iterates multiple times over the layers, trying to find node orderings that minimize the number of crossings. The algorithm uses randomization to increase the odds of finding a good result. To improve its results, consider increasing the Thoroughness option, which influences the number of iterations done. The Randomization seed also influences results.
  • INTERACTIVE
    Orders the nodes of each layer by comparing their positions before the layout algorithm was started. The idea is that the relative order of nodes as it was before layout was applied is not changed. This of course requires valid positions for all nodes to have been set on the input graph before calling the layout algorithm. The interactive layer sweep algorithm uses the Interactive Reference Point option to determine which reference point of nodes are used to compare positions.

Cycle Breaking

KLay Layered tries to position nodes in a way that all edges point rightwards. This is not possible if the input graph has cycles. Such cycles have to be broken by reversing as few edges as possible. The reversed edges end up pointing leftwards in the resulting diagram. There are different cycle breaking algorithms available:

  • GREEDY
    This algorithm reverses edges greedily. The algorithm tries to avoid edges that have the Priority property set.
  • INTERACTIVE
    The interactive algorithm tries to reverse edges that already pointed leftwards in the input graph. This requires node and port coordinates to have been set to sensible values.

Interactive Reference Point

Interactive layering and , crossing minimization, and cycle breaking algorithms use node positions to sort nodes into layers or to determine the order of nodes in each layer. However, it is unclear if for example the top left corners of nodes should be compared, or the bottom left corners — different settings might lead to different results. The interactive reference point determines which part of nodes is used to compare their positions. It provides the following settings:

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