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96 lines
2.2 KiB
Go
96 lines
2.2 KiB
Go
// Copyright ©2019 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 dot_test
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import (
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"fmt"
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"log"
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"math"
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"strconv"
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"gonum.org/v1/gonum/graph"
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"gonum.org/v1/gonum/graph/encoding"
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"gonum.org/v1/gonum/graph/encoding/dot"
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"gonum.org/v1/gonum/graph/simple"
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)
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// dotGraph provides a shim for interaction between the DOT
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// unmarshaler and a simple.WeightedUndirectedGraph.
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type dotGraph struct {
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*simple.WeightedUndirectedGraph
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}
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func newDotGraph() *dotGraph {
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return &dotGraph{WeightedUndirectedGraph: simple.NewWeightedUndirectedGraph(0, 0)}
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}
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// NewEdge returns a DOT-aware edge.
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func (g *dotGraph) NewEdge(from, to graph.Node) graph.Edge {
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e := g.WeightedUndirectedGraph.NewWeightedEdge(from, to, math.NaN()).(simple.WeightedEdge)
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return &weightedEdge{WeightedEdge: e}
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}
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// NewNode returns a DOT-aware node.
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func (g *dotGraph) NewNode() graph.Node {
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return &node{Node: g.WeightedUndirectedGraph.NewNode()}
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}
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// SetEdge is a shim to allow the DOT unmarshaler to
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// add weighted edges to a graph.
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func (g *dotGraph) SetEdge(e graph.Edge) {
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g.WeightedUndirectedGraph.SetWeightedEdge(e.(*weightedEdge))
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}
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// weightedEdge is a DOT-aware weighted edge.
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type weightedEdge struct {
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simple.WeightedEdge
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}
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// SetAttribute sets the weight of the receiver.
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func (e *weightedEdge) SetAttribute(attr encoding.Attribute) error {
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if attr.Key != "weight" {
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return fmt.Errorf("unable to unmarshal node DOT attribute with key %q", attr.Key)
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}
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var err error
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e.W, err = strconv.ParseFloat(attr.Value, 64)
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return err
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}
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// node is a DOT-aware node.
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type node struct {
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graph.Node
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dotID string
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}
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// SetDOTID sets the DOT ID of the node.
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func (n *node) SetDOTID(id string) { n.dotID = id }
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func (n *node) String() string { return n.dotID }
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const ug = `
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graph {
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a
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b
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c
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a--b ["weight"=0.5]
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a--c ["weight"=1]
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}
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`
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func ExampleUnmarshal_weighted() {
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dst := newDotGraph()
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err := dot.Unmarshal([]byte(ug), dst)
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if err != nil {
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log.Fatal(err)
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}
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for _, e := range graph.EdgesOf(dst.Edges()) {
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fmt.Printf("%+v\n", e.(*weightedEdge).WeightedEdge)
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}
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// Unordered output:
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// {F:a T:b W:0.5}
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// {F:a T:c W:1}
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}
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