Merge pull request #23 from elecbug/v0.6

Update v0.7.0

Author: elecbug

netkit.go

@@ -1,6 +1,2 @@
-// Package netkit provides common types and utilities used across this
-// repository.
+// Package netkit provides common types and utilities used across this repository.
 package netkit
-
-// Any is an alias for interface{} for convenience.
-type Any = interface{}

network-graph/algorithm/algorithm.go

@@ -1,55 +1,2 @@
 // Package algorithm provides graph algorithms for network analysis.
 package algorithm
-
-import (
-	"github.com/elecbug/netkit/network-graph/algorithm/config"
-	"github.com/elecbug/netkit/network-graph/graph"
-)
-
-// MetricType represents the type of metric to be calculated.
-type MetricType int
-
-// Metric types for graph analysis.
-const (
-	BETWEENNESS_CENTRALITY MetricType = iota
-	CLOSENESS_CENTRALITY
-	CLUSTERING_COEFFICIENT
-	DEGREE_ASSORTATIVITY_COEFFICIENT
-	DEGREE_CENTRALITY
-	DIAMETER
-	EDGE_BETWEENNESS_CENTRALITY
-	EIGENVECTOR_CENTRALITY
-	MODULARITY
-	PAGE_RANK
-	SHORTEST_PATHS
-)
-
-// Metric calculates the specified metric for the given graph.
-func Metric(g *graph.Graph, cfg *config.Config, metricType MetricType) any {
-	switch metricType {
-	case BETWEENNESS_CENTRALITY:
-		return BetweennessCentrality(g, cfg)
-	case CLOSENESS_CENTRALITY:
-		return ClosenessCentrality(g, cfg)
-	case CLUSTERING_COEFFICIENT:
-		return ClusteringCoefficient(g, cfg)
-	case DEGREE_ASSORTATIVITY_COEFFICIENT:
-		return DegreeAssortativityCoefficient(g, cfg)
-	case DEGREE_CENTRALITY:
-		return DegreeCentrality(g, cfg)
-	case DIAMETER:
-		return Diameter(g, cfg)
-	case EDGE_BETWEENNESS_CENTRALITY:
-		return EdgeBetweennessCentrality(g, cfg)
-	case EIGENVECTOR_CENTRALITY:
-		return EigenvectorCentrality(g, cfg)
-	case MODULARITY:
-		return Modularity(g, cfg)
-	case PAGE_RANK:
-		return PageRank(g, cfg)
-	case SHORTEST_PATHS:
-		return AllShortestPaths(g, cfg)
-	default:
-		return nil
-	}
-}

network-graph/graph/edge.go

@@ -25,7 +25,7 @@ func (g *Graph) AddEdge(from, to node.ID) error {
 
 	g.edges[from][to] = true
 
-	if g.bidirectional {
+	if g.isUndirected {
 		if _, ok := g.edges[to]; !ok {
 			g.edges[to] = make(map[node.ID]bool)
 		}
@@ -52,7 +52,7 @@ func (g *Graph) RemoveEdge(from, to node.ID) error {
 
 	delete(g.edges[from], to)
 
-	if g.bidirectional {
+	if g.isUndirected {
 		if _, ok := g.edges[to]; !ok {
 			g.edges[to] = make(map[node.ID]bool)
 		}

network-graph/graph/graph.go

@@ -12,17 +12,17 @@ import (
 
 // Graph maintains nodes and adjacency edges.
 type Graph struct {
-	nodes         map[node.ID]bool
-	edges         map[node.ID]map[node.ID]bool
-	bidirectional bool
+	nodes        map[node.ID]bool
+	edges        map[node.ID]map[node.ID]bool
+	isUndirected bool
 }
 
 // New creates and returns an empty Graph.
-func New(bidirectional bool) *Graph {
+func New(isUndirected bool) *Graph {
 	return &Graph{
-		nodes:         make(map[node.ID]bool),
-		edges:         make(map[node.ID]map[node.ID]bool),
-		bidirectional: bidirectional,
+		nodes:        make(map[node.ID]bool),
+		edges:        make(map[node.ID]map[node.ID]bool),
+		isUndirected: isUndirected,
 	}
 }
 
@@ -59,7 +59,7 @@ func Save(g *Graph) (string, error) {
 		return "", fmt.Errorf("failed to marshal edges: %v", err)
 	}
 
-	bidirectional, err := json.Marshal(g.bidirectional)
+	bidirectional, err := json.Marshal(g.isUndirected)
 
 	if err != nil {
 		return "", fmt.Errorf("failed to marshal bidirectional: %v", err)
@@ -92,15 +92,21 @@ func Load(data string) (*Graph, error) {
 	}
 
 	return &Graph{
-		nodes:         nodes,
-		edges:         edges,
-		bidirectional: bidirectional,
+		nodes:        nodes,
+		edges:        edges,
+		isUndirected: bidirectional,
 	}, nil
 }
 
+// [deprecated] This function is deprecated. Use graph.IsUndirected() instead.
 // IsBidirectional returns true if the graph is bidirectional.
 func (g *Graph) IsBidirectional() bool {
-	return g.bidirectional
+	return g.isUndirected
+}
+
+// IsUndirected returns true if the graph is undirected.
+func (g *Graph) IsUndirected() bool {
+	return g.isUndirected
 }
 
 // Hash returns the SHA-256 hash of the graph.

network-graph/graph/standard_graph/barabasi_albert.go

@@ -0,0 +1,63 @@
+package standard_graph
+
+import (
+	"github.com/elecbug/netkit/network-graph/graph"
+	"github.com/elecbug/netkit/network-graph/node"
+)
+
+// BarabasiAlbertGraph generates a graph based on the Barabási–Albert preferential attachment model.
+func BarabasiAlbertGraph(n int, m int, isUndirected bool) *graph.Graph {
+	if m < 1 || n <= m {
+		return nil
+	}
+
+	ra := genRand()
+	g := graph.New(isUndirected)
+
+	// --- 1. initialize ---
+	for i := 0; i < m; i++ {
+		g.AddNode(node.ID(toString(i)))
+	}
+	for i := 0; i < m; i++ {
+		for j := i + 1; j < m; j++ {
+			g.AddEdge(node.ID(toString(i)), node.ID(toString(j)))
+		}
+	}
+
+	// --- 2. preferential attachment ---
+	for i := m; i < n; i++ {
+		newNode := node.ID(toString(i))
+		g.AddNode(newNode)
+
+		// calculate current node degrees
+		degrees := make(map[node.ID]int)
+		totalDegree := 0
+		for _, id := range g.Nodes() {
+			d := len(g.Neighbors(id)) // each node degree
+			degrees[id] = d
+			totalDegree += d
+		}
+
+		// degree based sampling
+		chosen := make(map[node.ID]bool)
+		for len(chosen) < m {
+			r := ra.Intn(totalDegree)
+			accum := 0
+			var target node.ID
+			for id, d := range degrees {
+				accum += d
+				if r < accum {
+					target = id
+					break
+				}
+			}
+			// self-loop and duplicate edges are not allowed
+			if target != newNode && !chosen[target] {
+				g.AddEdge(newNode, target)
+				chosen[target] = true
+			}
+		}
+	}
+
+	return g
+}

network-graph/graph/standard_graph/erdos_reyni.go

@@ -0,0 +1,33 @@
+package standard_graph
+
+import (
+	"github.com/elecbug/netkit/network-graph/graph"
+	"github.com/elecbug/netkit/network-graph/node"
+)
+
+// ErdosRenyiGraph generates a random graph based on the Erdős-Rényi model.
+func ErdosRenyiGraph(n int, p float64, isUndirected bool) *graph.Graph {
+	ra := genRand()
+
+	g := graph.New(isUndirected)
+
+	if isUndirected {
+		for i := 0; i < n; i++ {
+			for j := i + 1; j < n; j++ {
+				if ra.Float64() < p {
+					g.AddEdge(node.ID(toString(i)), node.ID(toString(j)))
+				}
+			}
+		}
+	} else {
+		for i := 0; i < n; i++ {
+			for j := 0; j < n; j++ {
+				if i != j && ra.Float64() < p {
+					g.AddEdge(node.ID(toString(i)), node.ID(toString(j)))
+				}
+			}
+		}
+	}
+
+	return g
+}

network-graph/graph/standard_graph/random_geometric.go

@@ -0,0 +1,53 @@
+package standard_graph
+
+import (
+	"math"
+
+	"github.com/elecbug/netkit/network-graph/graph"
+	"github.com/elecbug/netkit/network-graph/node"
+)
+
+// RandomGeometricGraph generates a random geometric graph (RGG).
+// n = number of nodes
+// r = connection radius (0~1)
+// isUndirected = undirected or directed graph
+func RandomGeometricGraph(n int, r float64, isUndirected bool) *graph.Graph {
+	if n < 1 || r <= 0 {
+		return nil
+	}
+
+	ra := genRand()
+	g := graph.New(isUndirected)
+
+	// --- 1. Generate Nodes ---
+	type point struct{ x, y float64 }
+	positions := make(map[node.ID]point)
+
+	for i := 0; i < n; i++ {
+		id := node.ID(toString(i))
+		g.AddNode(id)
+		positions[id] = point{
+			x: ra.Float64(),
+			y: ra.Float64(),
+		}
+	}
+
+	// --- 2. Generate Edges ---
+	for i := 0; i < n; i++ {
+		for j := i + 1; j < n; j++ {
+			id1 := node.ID(toString(i))
+			id2 := node.ID(toString(j))
+			p1, p2 := positions[id1], positions[id2]
+
+			dx := p1.x - p2.x
+			dy := p1.y - p2.y
+			dist := math.Sqrt(dx*dx + dy*dy)
+
+			if dist <= r {
+				g.AddEdge(id1, id2)
+			}
+		}
+	}
+
+	return g
+}

network-graph/graph/standard_graph/random_regular.go

@@ -0,0 +1,82 @@
+package standard_graph
+
+import (
+	"github.com/elecbug/netkit/network-graph/graph"
+	"github.com/elecbug/netkit/network-graph/node"
+)
+
+// RandomRegularGraph generates a random k-regular graph with n nodes.
+// Each node has exactly degree k. Returns nil if impossible.
+func RandomRegularGraph(n, k int, isUndirected bool) *graph.Graph {
+	if k < 0 || n < 1 || k >= n {
+		return nil
+	}
+	if (n*k)%2 != 0 {
+		// if undirected, n*k must be even
+		return nil
+	}
+
+	ra := genRand()
+	g := graph.New(isUndirected)
+
+	// add nodes
+	for i := 0; i < n; i++ {
+		g.AddNode(node.ID(toString(i)))
+	}
+
+	// duplicate each node k times as stubs
+	stubs := make([]node.ID, 0, n*k)
+	for i := 0; i < n; i++ {
+		for j := 0; j < k; j++ {
+			stubs = append(stubs, node.ID(toString(i)))
+		}
+	}
+
+	// shuffle
+	ra.Shuffle(len(stubs), func(i, j int) { stubs[i], stubs[j] = stubs[j], stubs[i] })
+
+	// attempt to create edges (self-loop / duplicate prevention)
+	maxTries := n * k * 10
+	edges := make(map[[2]string]bool)
+	try := 0
+
+	for len(stubs) > 1 && try < maxTries {
+		a := stubs[len(stubs)-1]
+		b := stubs[len(stubs)-2]
+		stubs = stubs[:len(stubs)-2]
+
+		// self-loop is not allowed
+		if a == b {
+			// put them back and shuffle
+			stubs = append(stubs, a, b)
+			ra.Shuffle(len(stubs), func(i, j int) { stubs[i], stubs[j] = stubs[j], stubs[i] })
+			try++
+			continue
+		}
+
+		// if undirected, edge key must be sorted
+		key := [2]string{string(a), string(b)}
+		if isUndirected && key[0] > key[1] {
+			key[0], key[1] = key[1], key[0]
+		}
+
+		if edges[key] {
+			// edge already exists, put them back and shuffle
+			stubs = append(stubs, a, b)
+			ra.Shuffle(len(stubs), func(i, j int) { stubs[i], stubs[j] = stubs[j], stubs[i] })
+			try++
+			continue
+		}
+
+		// add edge
+		g.AddEdge(a, b)
+		edges[key] = true
+	}
+
+	if len(stubs) > 0 {
+		// if impossible to satisfy conditions
+		return nil
+	}
+
+	return g
+}