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355 lines
10 KiB
Go
355 lines
10 KiB
Go
// Copyright ©2014 The Gonum Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package multi
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import (
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"fmt"
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"gonum.org/v1/gonum/graph"
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"gonum.org/v1/gonum/graph/internal/uid"
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"gonum.org/v1/gonum/graph/iterator"
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)
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var (
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wug *WeightedUndirectedGraph
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_ graph.Graph = wug
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_ graph.Weighted = wug
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_ graph.Undirected = wug
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_ graph.WeightedUndirected = wug
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_ graph.Multigraph = wug
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_ graph.UndirectedMultigraph = wug
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_ graph.WeightedUndirectedMultigraph = wug
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_ graph.NodeAdder = wug
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_ graph.NodeRemover = wug
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_ graph.WeightedLineAdder = wug
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_ graph.LineRemover = wug
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)
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// WeightedUndirectedGraph implements a generalized undirected graph.
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type WeightedUndirectedGraph struct {
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// EdgeWEightFunc is used to provide
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// the WeightFunc function for WeightedEdge
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// values returned by the graph.
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// WeightFunc must accept a nil input.
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EdgeWeightFunc func(graph.WeightedLines) float64
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nodes map[int64]graph.Node
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lines map[int64]map[int64]map[int64]graph.WeightedLine
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nodeIDs uid.Set
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lineIDs uid.Set
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}
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// NewWeightedUndirectedGraph returns an WeightedUndirectedGraph.
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func NewWeightedUndirectedGraph() *WeightedUndirectedGraph {
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return &WeightedUndirectedGraph{
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nodes: make(map[int64]graph.Node),
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lines: make(map[int64]map[int64]map[int64]graph.WeightedLine),
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nodeIDs: uid.NewSet(),
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lineIDs: uid.NewSet(),
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}
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}
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// AddNode adds n to the graph. It panics if the added node ID matches an existing node ID.
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func (g *WeightedUndirectedGraph) AddNode(n graph.Node) {
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if _, exists := g.nodes[n.ID()]; exists {
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panic(fmt.Sprintf("simple: node ID collision: %d", n.ID()))
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}
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g.nodes[n.ID()] = n
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g.lines[n.ID()] = make(map[int64]map[int64]graph.WeightedLine)
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g.nodeIDs.Use(n.ID())
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}
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// Edge returns the edge from u to v if such an edge exists and nil otherwise.
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// The node v must be directly reachable from u as defined by the From method.
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// The returned graph.Edge is a multi.WeightedEdge if an edge exists.
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func (g *WeightedUndirectedGraph) Edge(uid, vid int64) graph.Edge {
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return g.WeightedEdge(uid, vid)
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}
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// EdgeBetween returns the edge between nodes x and y.
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func (g *WeightedUndirectedGraph) EdgeBetween(xid, yid int64) graph.Edge {
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return g.WeightedEdge(xid, yid)
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}
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// Edges returns all the edges in the graph. Each edge in the returned slice
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// is a multi.Edge.
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func (g *WeightedUndirectedGraph) Edges() graph.Edges {
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if len(g.lines) == 0 {
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return graph.Empty
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}
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var edges []graph.Edge
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seen := make(map[int64]struct{})
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for _, u := range g.lines {
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for _, e := range u {
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var lines []graph.WeightedLine
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for _, l := range e {
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lid := l.ID()
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if _, ok := seen[lid]; ok {
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continue
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}
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seen[lid] = struct{}{}
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lines = append(lines, l)
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}
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if len(lines) != 0 {
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edges = append(edges, WeightedEdge{
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F: g.Node(lines[0].From().ID()),
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T: g.Node(lines[0].To().ID()),
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WeightedLines: iterator.NewOrderedWeightedLines(lines),
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WeightFunc: g.EdgeWeightFunc,
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})
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}
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}
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}
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if len(edges) == 0 {
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return graph.Empty
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}
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return iterator.NewOrderedEdges(edges)
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}
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// From returns all nodes in g that can be reached directly from n.
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func (g *WeightedUndirectedGraph) From(id int64) graph.Nodes {
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if _, ok := g.nodes[id]; !ok {
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return graph.Empty
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}
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nodes := make([]graph.Node, len(g.lines[id]))
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i := 0
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for from := range g.lines[id] {
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nodes[i] = g.nodes[from]
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i++
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}
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if len(nodes) == 0 {
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return graph.Empty
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}
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return iterator.NewOrderedNodes(nodes)
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}
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// HasEdgeBetween returns whether an edge exists between nodes x and y.
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func (g *WeightedUndirectedGraph) HasEdgeBetween(xid, yid int64) bool {
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_, ok := g.lines[xid][yid]
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return ok
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}
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// Lines returns the lines from u to v if such an edge exists and nil otherwise.
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// The node v must be directly reachable from u as defined by the From method.
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func (g *WeightedUndirectedGraph) Lines(uid, vid int64) graph.Lines {
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return g.LinesBetween(uid, vid)
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}
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// LinesBetween returns the lines between nodes x and y.
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func (g *WeightedUndirectedGraph) LinesBetween(xid, yid int64) graph.Lines {
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edge := g.lines[xid][yid]
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if len(edge) == 0 {
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return graph.Empty
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}
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var lines []graph.Line
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seen := make(map[int64]struct{})
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for _, l := range edge {
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lid := l.ID()
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if _, ok := seen[lid]; ok {
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continue
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}
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seen[lid] = struct{}{}
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lines = append(lines, l)
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}
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return iterator.NewOrderedLines(lines)
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}
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// NewNode returns a new unique Node to be added to g. The Node's ID does
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// not become valid in g until the Node is added to g.
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func (g *WeightedUndirectedGraph) NewNode() graph.Node {
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if len(g.nodes) == 0 {
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return Node(0)
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}
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if int64(len(g.nodes)) == uid.Max {
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panic("simple: cannot allocate node: no slot")
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}
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return Node(g.nodeIDs.NewID())
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}
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// NewWeightedLine returns a new WeightedLine from the source to the destination node.
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// The returned WeightedLine will have a graph-unique ID.
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// The Line's ID does not become valid in g until the Line is added to g.
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func (g *WeightedUndirectedGraph) NewWeightedLine(from, to graph.Node, weight float64) graph.WeightedLine {
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return &WeightedLine{F: from, T: to, W: weight, UID: g.lineIDs.NewID()}
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}
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// Node returns the node with the given ID if it exists in the graph,
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// and nil otherwise.
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func (g *WeightedUndirectedGraph) Node(id int64) graph.Node {
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return g.nodes[id]
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}
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// Nodes returns all the nodes in the graph.
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func (g *WeightedUndirectedGraph) Nodes() graph.Nodes {
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if len(g.nodes) == 0 {
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return graph.Empty
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}
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nodes := make([]graph.Node, len(g.nodes))
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i := 0
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for _, n := range g.nodes {
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nodes[i] = n
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i++
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}
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return iterator.NewOrderedNodes(nodes)
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}
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// RemoveLine removes the line with the given end point and line IDs from the graph,
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// leaving the terminal nodes. If the line does not exist it is a no-op.
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func (g *WeightedUndirectedGraph) RemoveLine(fid, tid, id int64) {
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if _, ok := g.nodes[fid]; !ok {
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return
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}
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if _, ok := g.nodes[tid]; !ok {
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return
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}
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delete(g.lines[fid], tid)
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delete(g.lines[tid], fid)
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if len(g.lines[tid][fid]) == 0 {
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delete(g.lines[tid], fid)
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}
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g.lineIDs.Release(id)
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}
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// RemoveNode removes the node with the given ID from the graph, as well as any edges attached
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// to it. If the node is not in the graph it is a no-op.
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func (g *WeightedUndirectedGraph) RemoveNode(id int64) {
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if _, ok := g.nodes[id]; !ok {
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return
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}
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delete(g.nodes, id)
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for from := range g.lines[id] {
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delete(g.lines[from], id)
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}
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delete(g.lines, id)
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g.nodeIDs.Release(id)
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}
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// SetWeightedLine adds l, a line from one node to another. If the nodes do not exist, they are added
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// and are set to the nodes of the line otherwise.
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func (g *WeightedUndirectedGraph) SetWeightedLine(l graph.WeightedLine) {
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var (
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from = l.From()
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fid = from.ID()
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to = l.To()
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tid = to.ID()
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lid = l.ID()
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)
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if _, ok := g.nodes[fid]; !ok {
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g.AddNode(from)
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} else {
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g.nodes[fid] = from
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}
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if g.lines[fid][tid] == nil {
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g.lines[fid][tid] = make(map[int64]graph.WeightedLine)
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}
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if _, ok := g.nodes[tid]; !ok {
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g.AddNode(to)
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} else {
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g.nodes[tid] = to
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}
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if g.lines[tid][fid] == nil {
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g.lines[tid][fid] = make(map[int64]graph.WeightedLine)
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}
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g.lines[fid][tid][lid] = l
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g.lines[tid][fid][lid] = l
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g.lineIDs.Use(lid)
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}
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// Weight returns the weight for the lines between x and y summarised by the receiver's
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// EdgeWeightFunc. Weight returns true if an edge exists between x and y, false otherwise.
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func (g *WeightedUndirectedGraph) Weight(xid, yid int64) (w float64, ok bool) {
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lines := g.WeightedLines(xid, yid)
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return WeightedEdge{WeightedLines: lines, WeightFunc: g.EdgeWeightFunc}.Weight(), lines != nil
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}
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// WeightedEdge returns the weighted edge from u to v if such an edge exists and nil otherwise.
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// The node v must be directly reachable from u as defined by the From method.
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// The returned graph.WeightedEdge is a multi.WeightedEdge if an edge exists.
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func (g *WeightedUndirectedGraph) WeightedEdge(uid, vid int64) graph.WeightedEdge {
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lines := g.WeightedLines(uid, vid)
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if lines == nil {
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return nil
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}
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return WeightedEdge{
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F: g.Node(uid), T: g.Node(vid),
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WeightedLines: lines,
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WeightFunc: g.EdgeWeightFunc,
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}
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}
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// WeightedEdgeBetween returns the weighted edge between nodes x and y.
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func (g *WeightedUndirectedGraph) WeightedEdgeBetween(xid, yid int64) graph.WeightedEdge {
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return g.WeightedEdge(xid, yid)
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}
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// WeightedEdges returns all the edges in the graph. Each edge in the returned slice
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// is a multi.Edge.
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func (g *WeightedUndirectedGraph) WeightedEdges() graph.WeightedEdges {
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if len(g.lines) == 0 {
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return graph.Empty
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}
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var edges []graph.WeightedEdge
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seen := make(map[int64]struct{})
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for _, u := range g.lines {
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for _, e := range u {
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var lines []graph.WeightedLine
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for _, l := range e {
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lid := l.ID()
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if _, ok := seen[lid]; ok {
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continue
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}
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seen[lid] = struct{}{}
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lines = append(lines, l)
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}
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if len(lines) != 0 {
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edges = append(edges, WeightedEdge{
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F: g.Node(lines[0].From().ID()),
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T: g.Node(lines[0].To().ID()),
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WeightedLines: iterator.NewOrderedWeightedLines(lines),
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WeightFunc: g.EdgeWeightFunc,
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})
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}
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}
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}
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if len(edges) == 0 {
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return graph.Empty
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}
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return iterator.NewOrderedWeightedEdges(edges)
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}
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// WeightedLines returns the lines from u to v if such an edge exists and nil otherwise.
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// The node v must be directly reachable from u as defined by the From method.
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func (g *WeightedUndirectedGraph) WeightedLines(uid, vid int64) graph.WeightedLines {
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return g.WeightedLinesBetween(uid, vid)
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}
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// WeightedLinesBetween returns the lines between nodes x and y.
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func (g *WeightedUndirectedGraph) WeightedLinesBetween(xid, yid int64) graph.WeightedLines {
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edge := g.lines[xid][yid]
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if len(edge) == 0 {
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return graph.Empty
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}
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var lines []graph.WeightedLine
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seen := make(map[int64]struct{})
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for _, l := range edge {
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lid := l.ID()
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if _, ok := seen[lid]; ok {
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continue
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}
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seen[lid] = struct{}{}
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lines = append(lines, l)
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}
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return iterator.NewOrderedWeightedLines(lines)
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}
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