108 lines
2.3 KiB
Go
108 lines
2.3 KiB
Go
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/*
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Copyright © 2025 filifa
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package markov
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import (
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"errors"
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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/simple"
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)
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type AbsorbingMarkovChain struct {
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*simple.WeightedDirectedGraph
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}
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func NewAbsorbingMarkovChain() *AbsorbingMarkovChain {
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return &AbsorbingMarkovChain{WeightedDirectedGraph: simple.NewWeightedDirectedGraph(math.NaN(), math.NaN())}
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}
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func (g *AbsorbingMarkovChain) IsValid() bool {
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for nodes := g.Nodes(); nodes.Next(); {
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u := nodes.Node().(*node)
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if g.From(u.ID()).Len() == 0 {
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continue
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}
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if g.outWeightSum(u) != 1 {
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return false
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}
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}
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return true
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}
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func (g *AbsorbingMarkovChain) outWeightSum(u *node) float64 {
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sum := 0.0
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for nodes := g.From(u.ID()); nodes.Next(); {
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v := nodes.Node()
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e := g.WeightedEdge(u.ID(), v.ID())
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if e != nil {
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sum += e.(*weightedEdge).W
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}
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}
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return sum
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}
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func (g *AbsorbingMarkovChain) NewEdge(from, to graph.Node) graph.Edge {
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e := g.WeightedDirectedGraph.NewWeightedEdge(from, to, math.NaN()).(simple.WeightedEdge)
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return &weightedEdge{WeightedEdge: e}
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}
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func (g *AbsorbingMarkovChain) NewNode() graph.Node {
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return &node{Node: g.WeightedDirectedGraph.NewNode()}
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}
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func (g *AbsorbingMarkovChain) SetEdge(e graph.Edge) {
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g.WeightedDirectedGraph.SetWeightedEdge(e.(*weightedEdge))
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}
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type weightedEdge struct {
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simple.WeightedEdge
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}
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func (e *weightedEdge) SetAttribute(attr encoding.Attribute) error {
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var err error
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switch attr.Key {
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case "weight":
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e.W, err = strconv.ParseFloat(attr.Value, 64)
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default:
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err = errors.New("unknown key" + attr.Key)
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}
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return err
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}
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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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func (n *node) SetDOTID(id string) {
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n.dotID = id
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}
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func (n *node) DOTID() string {
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return n.dotID
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}
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