ghc-9.10.0.20240426: The GHC API
Safe HaskellNone
LanguageGHC2021

GHC.Data.Graph.Color

Description

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

Synopsis

Documentation

colorGraph Source #

Arguments

:: (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 cls (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 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.