Get a new layout, which can be used to algorithmically position the nodes in the collection. This function is useful for running a layout on a subset of the elements in the graph, perhaps in parallel to other layouts.
You must specify options.name with the name of the layout you wish to use.
Note: that you must call layout.run() in order for it to affect the graph.
The layout options.
http://js.cytoscape.org/#collection/layout