y3

I started to work on adjacent node swapping to reduce edge crossings in the graph. I implemented the first part, which is positioning (on the x-axis) each node at the median of the positions of nodes pointing at it from previous layers.

That's when I noticed things still looked messed up and that some nodes were pointing to nodes that were in the same vertical layer. I reread the book to make sure that's not supposed to happen.

Then, I wrote a test to confirm that it was happening:

  for (
    let i = 0;
    i <= layeredNodesResult[layeredNodesResult.length - 1].layer;
    ++i
  ) {
    let layerNodes = layeredNodesResult.filter((e) => e.layer === i);
    // console.log('Layer', i, layerNodes);
    t.ok(
      layerNodes.every((node) =>
        layerNodes.every(
          (otherNode) =>
            !otherNode.nodesPointingAtThisNode.includes(node.endeavor.id)
        )
      ),
      `Layer ${i} does not have nodes pointing at each other.`
    );
  }

And yes, it is happening. So, I have to step back and see what I did wrong in the layering part of the algorithm instead moving forward with edge crossing reduction.