Parallel Layout error

I was trying out the Parallel Layout provided at Parallel.html

I have downloaded the js file that is mentioned on the link and then required the file in my project.

Initialized it a follows

layout = $$(ParallelLayout, { layerSpacing: 20, nodeSpacing: 10 });
goDiagram.startTransaction( '_toggleLayout' );
goDiagram.layout = layout;
goDiagram.commitTransaction( '_toggleLayout' );

The require does not throw any error but toggle layout I am receiving the following error in my browser console.

go-debug.js:31 Uncaught Error: LayoutNetwork.findVertex:node value is not an instance of Node: undefined
at Object.k (go-debug.js:31)
at Object.hc (go-debug.js:33)
at Object.l (go-debug.js:32)
at ov.ya.findVertex.ya.Qn (go-debug.js:1827)
at ParallelLayout.commitNodes (ParallelLayout.js:72)
at ParallelLayout.Z.commitLayout (go-debug.js:2092)
at (go-debug.js:1813)
at ParallelLayout.Z.doLayout (go-debug.js:2035)
at em (go-debug.js:966)
at Vi (go-debug.js:826)

I don’t understand what am I doing wrong ? Tree, Layered, forced all work as expected.

If you read the ParallelLayout.js code, you will see that it requires every graph to have both a “Split” node and a “Merge” node. Might the layout not be finding those two special nodes?

I missed this part, Due to this requirement this layout is not useful to me.

Thanks walter.