ghc-8.0.2: The GHC API

Safe HaskellNone



Graph Coloring. This is a generic graph coloring library, abstracted over the type of the node keys, nodes and colors.



module GraphBase

module GraphOps

module GraphPpr

colorGraph #


:: (Uniquable k, Uniquable cls, Uniquable color, Eq cls, Ord k, Outputable k, Outputable cls, Outputable color) 
=> Bool

whether to do iterative coalescing

-> Int

how many times we've tried to color this graph so far.

-> UniqFM (UniqSet color)

map of (node class -> set of colors available for this class).

-> Triv k cls color

fn to decide whether a node is trivially colorable.

-> (Graph k cls color -> k)

fn to choose a node to potentially leave uncolored if nothing is trivially colorable.

-> Graph k cls color

the graph to color.

-> (Graph k cls color, UniqSet k, UniqFM k) 

Try to color a graph with this set of colors. Uses Chaitin's algorithm to color the graph. The graph is scanned for nodes which are deamed 'trivially colorable'. These nodes are pushed onto a stack and removed from the graph. Once this process is complete the graph can be colored by removing nodes from the stack (ie in reverse order) and assigning them colors different to their neighbors.