nodeIDMap := make(map[*Node]int)
	hasNodelets := make(map[*Node]bool)

	maxFlat := float64(abs64(g.Nodes[0].FlatValue()))
	for i, n := range g.Nodes {
		nodeIDMap[n] = i + 1
		if float64(abs64(n.FlatValue())) > maxFlat {
			maxFlat = float64(abs64(n.FlatValue()))
		}
	}

	edges := EdgeMap{}

	// Add nodes and nodelets to DOT builder.
	for _, n := range g.Nodes {

				fmt.Fprintf(w, "%10s %10s %10x: %s\n",
					valueOrDot(n.flatValue(), rpt),
					valueOrDot(n.cumValue(), rpt),
					n.address, n.instruction,
				)
			case len(n.instruction) < 40:
				// Short instruction, print loc on the same line.
				fmt.Fprintf(w, "%10s %10s %10x: %-40s;%s\n",
					valueOrDot(n.flatValue(), rpt),
					valueOrDot(n.cumValue(), rpt),
					n.address, n.instruction,
					locStr,

	// to, or "" for numeric tags not associated to a label tag.
	NumericTags map[string]TagMap
}

// FlatValue returns the exclusive value for this node, computing the
// mean if a divisor is available.
func (n *Node) FlatValue() int64 {
	if n.FlatDiv == 0 {
		return n.Flat
	}
	return n.Flat / n.FlatDiv
}

}

// Graph summarizes a performance profile into a format that is
// suitable for visualization.
type Graph struct {
	Nodes Nodes
}

// FlatValue returns the exclusive value for this node, computing the
// mean if a divisor is available.
func (n *Node) FlatValue() int64 {
	if n.FlatDiv == 0 {
		return n.Flat
	}
	return n.Flat / n.FlatDiv
}

// CumValue returns the inclusive value for this node, computing the