Esempio n. 1
0
func NewColorHeap(src *graph.Node) Heap {
	h := Heap{Items: make([]Heaper, graph.NumColors-1)}
	for i := int(graph.Blank + 1); i < graph.NumColors; i++ {
		h.Items[i-1] = ColorItem{
			Color: graph.NodeColor(i),
		}
	}

	for _, adj := range src.Adj {
		if adj.Color == graph.Blank {
			for i := graph.Blank + 1; i < graph.NumColors; i++ {
				priority := h.Items[i-1].(ColorItem)
				priority.Priority += adj.TakenColors[i]
				h.Items[i-1] = priority
			}
		}
	}

	heap.Init(&h)
	return h
}
Esempio n. 2
0
// Setup for graph coloring backtracking algorithm,
// search heuristics are set based on heuristc flag
func colorMap(g graph.Graph) bool {

	// For MRV, we'll use a heap
	var h nh.Heap
	if Heuristic.MRV {
		h = nh.NewNodeHeap(len(g), Heuristic.Degree)
		for _, n := range g {
			h.Items = append(h.Items, nh.NewNodeItem(n))
		}
		heap.Init(&h)
	}

	// Init colors cache
	ColorsCache.Colors = make([][]graph.NodeColor, len(g))
	for i := range g {
		ColorsCache.Colors[i] = make([]graph.NodeColor, 0, graph.NumColors-1)
		for color := graph.Blank + 1; color < graph.NumColors; color++ {
			ColorsCache.Colors[i] = append(ColorsCache.Colors[i], graph.NodeColor(color))
		}
	}

	return colorMapBacktrack(g, 0, &h)
}