package dagro

// rank selects one of Dagre's three rankers. Unknown and absent values
// intentionally fall back to network simplex.
func rank( *Graph) {
	 := ""
	if  := asAttrs(.Graph());  != nil {
		 = stringValue(, "ranker")
	}

	switch  {
	case "longest-path":
		longestPath()
	case "tight-tree":
		longestPath()
		feasibleTree()
	case "network-simplex":
		networkSimplex()
	default:
		networkSimplex()
	}
}