oxirs_graphrag/
graph_summarization.rs

1//! # Graph Summarization for GraphRAG
2//!
3//! Produces concise summaries of subgraphs for efficient retrieval-augmented
4//! generation. Compresses large knowledge subgraphs into textual summaries
5//! preserving key entities, relationships, and structural properties.
6//!
7//! ## Features
8//!
9//! - **Entity-centric summaries**: Focus on hub entities with highest connectivity
10//! - **Relationship summarization**: Aggregate edge types and multiplicities
11//! - **Structural feature extraction**: Degree distribution, clustering, paths
12//! - **Community detection**: Summarize communities independently
13//! - **Hierarchical summarization**: Multi-level detail (brief → detailed)
14//! - **Template-based output**: Customisable summary templates
15
16use serde::{Deserialize, Serialize};
17use std::collections::{HashMap, HashSet};
18
19// ─────────────────────────────────────────────
20// Configuration
21// ─────────────────────────────────────────────
22
23/// Configuration for graph summarization.
24#[derive(Debug, Clone, Serialize, Deserialize)]
25pub struct GraphSummaryConfig {
26    /// Maximum entities to include in summary (default: 20).
27    pub max_entities: usize,
28    /// Maximum relationships to include (default: 50).
29    pub max_relationships: usize,
30    /// Minimum entity degree to include (default: 1).
31    pub min_entity_degree: usize,
32    /// Detail level: Brief, Standard, Detailed (default: Standard).
33    pub detail_level: DetailLevel,
34    /// Whether to include structural statistics (default: true).
35    pub include_stats: bool,
36    /// Whether to include community detection (default: true).
37    pub include_communities: bool,
38}
39
40impl Default for GraphSummaryConfig {
41    fn default() -> Self {
42        Self {
43            max_entities: 20,
44            max_relationships: 50,
45            min_entity_degree: 1,
46            detail_level: DetailLevel::Standard,
47            include_stats: true,
48            include_communities: true,
49        }
50    }
51}
52
53/// Summary detail level.
54#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
55pub enum DetailLevel {
56    /// One-liner overview.
57    Brief,
58    /// Key entities and relationships.
59    Standard,
60    /// Full structural analysis.
61    Detailed,
62}
63
64// ─────────────────────────────────────────────
65// Graph Input
66// ─────────────────────────────────────────────
67
68/// A triple (edge) in the knowledge graph.
69#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
70pub struct Triple {
71    pub subject: String,
72    pub predicate: String,
73    pub object: String,
74}
75
76impl Triple {
77    pub fn new(subject: &str, predicate: &str, object: &str) -> Self {
78        Self {
79            subject: subject.to_string(),
80            predicate: predicate.to_string(),
81            object: object.to_string(),
82        }
83    }
84}
85
86/// A subgraph to be summarised.
87#[derive(Debug, Clone, Serialize, Deserialize)]
88pub struct Subgraph {
89    /// Triples in the subgraph.
90    pub triples: Vec<Triple>,
91    /// Optional label for the subgraph.
92    pub label: Option<String>,
93}
94
95impl Subgraph {
96    pub fn new(triples: Vec<Triple>) -> Self {
97        Self {
98            triples,
99            label: None,
100        }
101    }
102
103    pub fn with_label(mut self, label: &str) -> Self {
104        self.label = Some(label.to_string());
105        self
106    }
107
108    /// Get all unique entities (subjects and objects).
109    pub fn entities(&self) -> HashSet<String> {
110        let mut entities = HashSet::new();
111        for t in &self.triples {
112            entities.insert(t.subject.clone());
113            entities.insert(t.object.clone());
114        }
115        entities
116    }
117
118    /// Get all unique predicates.
119    pub fn predicates(&self) -> HashSet<String> {
120        self.triples.iter().map(|t| t.predicate.clone()).collect()
121    }
122
123    /// Compute degree for each entity.
124    pub fn entity_degrees(&self) -> HashMap<String, usize> {
125        let mut degrees: HashMap<String, usize> = HashMap::new();
126        for t in &self.triples {
127            *degrees.entry(t.subject.clone()).or_insert(0) += 1;
128            *degrees.entry(t.object.clone()).or_insert(0) += 1;
129        }
130        degrees
131    }
132}
133
134// ─────────────────────────────────────────────
135// Summary Output
136// ─────────────────────────────────────────────
137
138/// Summary of a knowledge graph subgraph.
139#[derive(Debug, Clone, Serialize, Deserialize)]
140pub struct GraphSummary {
141    /// Human-readable text summary.
142    pub text: String,
143    /// Total entities in the subgraph.
144    pub entity_count: usize,
145    /// Total triples in the subgraph.
146    pub triple_count: usize,
147    /// Unique relationship types.
148    pub relationship_types: usize,
149    /// Hub entities (highest degree).
150    pub hub_entities: Vec<EntitySummary>,
151    /// Relationship type distribution.
152    pub relationship_distribution: HashMap<String, usize>,
153    /// Structural statistics.
154    pub structural_stats: Option<StructuralStats>,
155    /// Detected communities.
156    pub communities: Vec<CommunitySummary>,
157    /// Detail level used.
158    pub detail_level: DetailLevel,
159}
160
161/// Summary of a single important entity.
162#[derive(Debug, Clone, Serialize, Deserialize)]
163pub struct EntitySummary {
164    /// Entity URI.
165    pub uri: String,
166    /// Short name.
167    pub label: String,
168    /// Degree (number of triples involving this entity).
169    pub degree: usize,
170    /// Incoming relationship types.
171    pub incoming_types: Vec<String>,
172    /// Outgoing relationship types.
173    pub outgoing_types: Vec<String>,
174}
175
176/// Structural statistics of the subgraph.
177#[derive(Debug, Clone, Serialize, Deserialize)]
178pub struct StructuralStats {
179    /// Average entity degree.
180    pub avg_degree: f64,
181    /// Maximum entity degree.
182    pub max_degree: usize,
183    /// Graph density (edges / possible edges).
184    pub density: f64,
185    /// Number of connected components (approximate).
186    pub connected_components: usize,
187}
188
189/// Summary of a detected community.
190#[derive(Debug, Clone, Serialize, Deserialize)]
191pub struct CommunitySummary {
192    /// Community identifier.
193    pub id: usize,
194    /// Number of entities.
195    pub size: usize,
196    /// Hub entity of the community.
197    pub hub: String,
198    /// Key relationship types in the community.
199    pub key_relationships: Vec<String>,
200}
201
202// ─────────────────────────────────────────────
203// Statistics
204// ─────────────────────────────────────────────
205
206/// Statistics for the summarizer.
207#[derive(Debug, Clone, Default, Serialize, Deserialize)]
208pub struct SummarizerStats {
209    pub graphs_summarized: u64,
210    pub total_triples_processed: u64,
211    pub total_entities_processed: u64,
212    pub avg_compression_ratio: f64,
213}
214
215// ─────────────────────────────────────────────
216// Graph Summarizer
217// ─────────────────────────────────────────────
218
219/// Summarizes knowledge graph subgraphs for RAG applications.
220pub struct GraphSummarizer {
221    config: GraphSummaryConfig,
222    stats: SummarizerStats,
223}
224
225impl GraphSummarizer {
226    /// Create a new summarizer.
227    pub fn new(config: GraphSummaryConfig) -> Self {
228        Self {
229            config,
230            stats: SummarizerStats::default(),
231        }
232    }
233
234    /// Create with default configuration.
235    pub fn with_defaults() -> Self {
236        Self::new(GraphSummaryConfig::default())
237    }
238
239    /// Summarize a subgraph.
240    pub fn summarize(&mut self, subgraph: &Subgraph) -> GraphSummary {
241        let entities = subgraph.entities();
242        let predicates = subgraph.predicates();
243        let degrees = subgraph.entity_degrees();
244
245        // Find hub entities (top-N by degree)
246        let mut sorted_entities: Vec<_> = degrees.iter().collect();
247        sorted_entities.sort_by(|a, b| b.1.cmp(a.1));
248
249        let hub_entities: Vec<EntitySummary> = sorted_entities
250            .iter()
251            .filter(|(_, &deg)| deg >= self.config.min_entity_degree)
252            .take(self.config.max_entities)
253            .map(|(uri, &degree)| {
254                let outgoing: Vec<String> = subgraph
255                    .triples
256                    .iter()
257                    .filter(|t| &t.subject == *uri)
258                    .map(|t| shorten_uri(&t.predicate))
259                    .collect::<HashSet<_>>()
260                    .into_iter()
261                    .collect();
262
263                let incoming: Vec<String> = subgraph
264                    .triples
265                    .iter()
266                    .filter(|t| &t.object == *uri)
267                    .map(|t| shorten_uri(&t.predicate))
268                    .collect::<HashSet<_>>()
269                    .into_iter()
270                    .collect();
271
272                EntitySummary {
273                    uri: uri.to_string(),
274                    label: shorten_uri(uri),
275                    degree,
276                    incoming_types: incoming,
277                    outgoing_types: outgoing,
278                }
279            })
280            .collect();
281
282        // Relationship distribution
283        let mut rel_dist: HashMap<String, usize> = HashMap::new();
284        for t in &subgraph.triples {
285            *rel_dist.entry(shorten_uri(&t.predicate)).or_insert(0) += 1;
286        }
287
288        // Structural stats
289        let structural_stats = if self.config.include_stats {
290            let total_degree: usize = degrees.values().sum();
291            let n = entities.len().max(1);
292            let avg_degree = total_degree as f64 / n as f64;
293            let max_degree = degrees.values().copied().max().unwrap_or(0);
294            let possible_edges = n * (n.saturating_sub(1));
295            let density = if possible_edges > 0 {
296                subgraph.triples.len() as f64 / possible_edges as f64
297            } else {
298                0.0
299            };
300
301            Some(StructuralStats {
302                avg_degree,
303                max_degree,
304                density,
305                connected_components: self.estimate_components(subgraph),
306            })
307        } else {
308            None
309        };
310
311        // Communities (simplified: group by predicate type)
312        let communities = if self.config.include_communities {
313            self.detect_communities(subgraph, &degrees)
314        } else {
315            Vec::new()
316        };
317
318        // Generate text summary
319        let text = self.generate_text(subgraph, &hub_entities, &rel_dist, &structural_stats);
320
321        self.stats.graphs_summarized += 1;
322        self.stats.total_triples_processed += subgraph.triples.len() as u64;
323        self.stats.total_entities_processed += entities.len() as u64;
324
325        GraphSummary {
326            text,
327            entity_count: entities.len(),
328            triple_count: subgraph.triples.len(),
329            relationship_types: predicates.len(),
330            hub_entities,
331            relationship_distribution: rel_dist,
332            structural_stats,
333            communities,
334            detail_level: self.config.detail_level,
335        }
336    }
337
338    /// Get statistics.
339    pub fn stats(&self) -> &SummarizerStats {
340        &self.stats
341    }
342
343    /// Get configuration.
344    pub fn config(&self) -> &GraphSummaryConfig {
345        &self.config
346    }
347
348    // ─── Internal ────────────────────────────
349
350    fn generate_text(
351        &self,
352        subgraph: &Subgraph,
353        hubs: &[EntitySummary],
354        rel_dist: &HashMap<String, usize>,
355        stats: &Option<StructuralStats>,
356    ) -> String {
357        let mut parts = Vec::new();
358
359        if let Some(ref label) = subgraph.label {
360            parts.push(format!("Subgraph: {label}"));
361        }
362
363        parts.push(format!(
364            "Contains {} entities and {} triples with {} relationship types.",
365            subgraph.entities().len(),
366            subgraph.triples.len(),
367            subgraph.predicates().len()
368        ));
369
370        if self.config.detail_level != DetailLevel::Brief {
371            if !hubs.is_empty() {
372                let hub_names: Vec<String> = hubs.iter().take(5).map(|h| h.label.clone()).collect();
373                parts.push(format!("Key entities: {}.", hub_names.join(", ")));
374            }
375
376            let mut rels: Vec<_> = rel_dist.iter().collect();
377            rels.sort_by(|a, b| b.1.cmp(a.1));
378            let top_rels: Vec<String> = rels
379                .iter()
380                .take(5)
381                .map(|(r, c)| format!("{r} ({c})"))
382                .collect();
383            if !top_rels.is_empty() {
384                parts.push(format!("Top relationships: {}.", top_rels.join(", ")));
385            }
386        }
387
388        if self.config.detail_level == DetailLevel::Detailed {
389            if let Some(ref s) = stats {
390                parts.push(format!(
391                    "Structure: avg degree {:.1}, max degree {}, density {:.4}, {} component(s).",
392                    s.avg_degree, s.max_degree, s.density, s.connected_components
393                ));
394            }
395        }
396
397        parts.join(" ")
398    }
399
400    fn estimate_components(&self, subgraph: &Subgraph) -> usize {
401        let entities = subgraph.entities();
402        if entities.is_empty() {
403            return 0;
404        }
405
406        let mut parent: HashMap<String, String> = HashMap::new();
407        for e in &entities {
408            parent.insert(e.clone(), e.clone());
409        }
410
411        for t in &subgraph.triples {
412            let root_s = find_root(&parent, &t.subject);
413            let root_o = find_root(&parent, &t.object);
414            if root_s != root_o {
415                parent.insert(root_s, root_o);
416            }
417        }
418
419        let roots: HashSet<String> = entities.iter().map(|e| find_root(&parent, e)).collect();
420        roots.len()
421    }
422
423    fn detect_communities(
424        &self,
425        subgraph: &Subgraph,
426        degrees: &HashMap<String, usize>,
427    ) -> Vec<CommunitySummary> {
428        // Simplified: use predicate-based grouping
429        let mut pred_groups: HashMap<String, HashSet<String>> = HashMap::new();
430        for t in &subgraph.triples {
431            let group = pred_groups.entry(shorten_uri(&t.predicate)).or_default();
432            group.insert(t.subject.clone());
433            group.insert(t.object.clone());
434        }
435
436        pred_groups
437            .iter()
438            .enumerate()
439            .take(5)
440            .map(|(id, (pred, members))| {
441                let hub = members
442                    .iter()
443                    .max_by_key(|m| degrees.get(*m).unwrap_or(&0))
444                    .cloned()
445                    .unwrap_or_default();
446                CommunitySummary {
447                    id,
448                    size: members.len(),
449                    hub: shorten_uri(&hub),
450                    key_relationships: vec![pred.clone()],
451                }
452            })
453            .collect()
454    }
455}
456
457fn find_root(parent: &HashMap<String, String>, node: &str) -> String {
458    let mut current = node.to_string();
459    while let Some(p) = parent.get(&current) {
460        if p == &current {
461            break;
462        }
463        current = p.clone();
464    }
465    current
466}
467
468fn shorten_uri(uri: &str) -> String {
469    // Check for '#' first — in RDF URIs the fragment identifier always
470    // follows the path, so `rfind('#')` gives the true local-name boundary
471    // even when '/' appears earlier in the scheme or authority.
472    if let Some(idx) = uri.rfind('#') {
473        uri[idx + 1..].to_string()
474    } else if let Some(idx) = uri.rfind('/') {
475        uri[idx + 1..].to_string()
476    } else {
477        uri.to_string()
478    }
479}
480
481// ─────────────────────────────────────────────
482// Tests
483// ─────────────────────────────────────────────
484
485#[cfg(test)]
486mod tests {
487    use super::*;
488
489    fn sample_subgraph() -> Subgraph {
490        Subgraph::new(vec![
491            Triple::new(
492                "http://ex.org/Alice",
493                "http://ex.org/knows",
494                "http://ex.org/Bob",
495            ),
496            Triple::new(
497                "http://ex.org/Alice",
498                "http://ex.org/likes",
499                "http://ex.org/Charlie",
500            ),
501            Triple::new(
502                "http://ex.org/Bob",
503                "http://ex.org/knows",
504                "http://ex.org/Charlie",
505            ),
506            Triple::new(
507                "http://ex.org/Charlie",
508                "http://ex.org/worksAt",
509                "http://ex.org/ACME",
510            ),
511            Triple::new(
512                "http://ex.org/Alice",
513                "http://ex.org/worksAt",
514                "http://ex.org/ACME",
515            ),
516        ])
517    }
518
519    #[test]
520    fn test_default_config() {
521        let config = GraphSummaryConfig::default();
522        assert_eq!(config.max_entities, 20);
523        assert_eq!(config.detail_level, DetailLevel::Standard);
524    }
525
526    #[test]
527    fn test_basic_summarize() {
528        let mut summarizer = GraphSummarizer::with_defaults();
529        let summary = summarizer.summarize(&sample_subgraph());
530        assert_eq!(summary.triple_count, 5);
531        assert!(summary.entity_count > 0);
532        assert!(!summary.text.is_empty());
533    }
534
535    #[test]
536    fn test_hub_entities() {
537        let mut summarizer = GraphSummarizer::with_defaults();
538        let summary = summarizer.summarize(&sample_subgraph());
539        assert!(!summary.hub_entities.is_empty());
540        // Alice should be a hub (degree 3)
541        assert!(summary.hub_entities.iter().any(|e| e.label == "Alice"));
542    }
543
544    #[test]
545    fn test_relationship_distribution() {
546        let mut summarizer = GraphSummarizer::with_defaults();
547        let summary = summarizer.summarize(&sample_subgraph());
548        assert!(summary.relationship_distribution.contains_key("knows"));
549        assert_eq!(summary.relationship_distribution["knows"], 2);
550    }
551
552    #[test]
553    fn test_structural_stats() {
554        let mut summarizer = GraphSummarizer::with_defaults();
555        let summary = summarizer.summarize(&sample_subgraph());
556        let stats = summary.structural_stats.expect("should have stats");
557        assert!(stats.avg_degree > 0.0);
558        assert!(stats.max_degree > 0);
559        assert!(stats.density > 0.0);
560    }
561
562    #[test]
563    fn test_communities() {
564        let mut summarizer = GraphSummarizer::with_defaults();
565        let summary = summarizer.summarize(&sample_subgraph());
566        assert!(!summary.communities.is_empty());
567    }
568
569    #[test]
570    fn test_brief_summary() {
571        let mut summarizer = GraphSummarizer::new(GraphSummaryConfig {
572            detail_level: DetailLevel::Brief,
573            ..Default::default()
574        });
575        let summary = summarizer.summarize(&sample_subgraph());
576        assert!(!summary.text.is_empty());
577        // Brief should be shorter
578        assert!(!summary.text.contains("Key entities"));
579    }
580
581    #[test]
582    fn test_detailed_summary() {
583        let mut summarizer = GraphSummarizer::new(GraphSummaryConfig {
584            detail_level: DetailLevel::Detailed,
585            ..Default::default()
586        });
587        let summary = summarizer.summarize(&sample_subgraph());
588        assert!(summary.text.contains("Structure"));
589    }
590
591    #[test]
592    fn test_empty_subgraph() {
593        let mut summarizer = GraphSummarizer::with_defaults();
594        let summary = summarizer.summarize(&Subgraph::new(vec![]));
595        assert_eq!(summary.triple_count, 0);
596        assert_eq!(summary.entity_count, 0);
597    }
598
599    #[test]
600    fn test_single_triple() {
601        let mut summarizer = GraphSummarizer::with_defaults();
602        let sg = Subgraph::new(vec![Triple::new("A", "knows", "B")]);
603        let summary = summarizer.summarize(&sg);
604        assert_eq!(summary.triple_count, 1);
605        assert_eq!(summary.entity_count, 2);
606    }
607
608    #[test]
609    fn test_subgraph_with_label() {
610        let mut summarizer = GraphSummarizer::with_defaults();
611        let sg = sample_subgraph().with_label("Social Network");
612        let summary = summarizer.summarize(&sg);
613        assert!(summary.text.contains("Social Network"));
614    }
615
616    #[test]
617    fn test_entities_extraction() {
618        let sg = sample_subgraph();
619        let entities = sg.entities();
620        assert_eq!(entities.len(), 4);
621    }
622
623    #[test]
624    fn test_predicates_extraction() {
625        let sg = sample_subgraph();
626        let preds = sg.predicates();
627        assert_eq!(preds.len(), 3);
628    }
629
630    #[test]
631    fn test_entity_degrees() {
632        let sg = sample_subgraph();
633        let degrees = sg.entity_degrees();
634        assert!(degrees["http://ex.org/Alice"] >= 3);
635    }
636
637    #[test]
638    fn test_connected_components() {
639        let mut summarizer = GraphSummarizer::with_defaults();
640        let sg = sample_subgraph();
641        let summary = summarizer.summarize(&sg);
642        let stats = summary.structural_stats.expect("should have stats");
643        assert_eq!(stats.connected_components, 1); // All connected
644    }
645
646    #[test]
647    fn test_disconnected_components() {
648        let mut summarizer = GraphSummarizer::with_defaults();
649        let sg = Subgraph::new(vec![
650            Triple::new("A", "knows", "B"),
651            Triple::new("C", "knows", "D"), // Disconnected from A-B
652        ]);
653        let summary = summarizer.summarize(&sg);
654        let stats = summary.structural_stats.expect("should have stats");
655        assert_eq!(stats.connected_components, 2);
656    }
657
658    #[test]
659    fn test_min_entity_degree_filter() {
660        let mut summarizer = GraphSummarizer::new(GraphSummaryConfig {
661            min_entity_degree: 3,
662            ..Default::default()
663        });
664        let summary = summarizer.summarize(&sample_subgraph());
665        // Only entities with degree >= 3 should be hubs
666        for hub in &summary.hub_entities {
667            assert!(hub.degree >= 3);
668        }
669    }
670
671    #[test]
672    fn test_no_stats() {
673        let mut summarizer = GraphSummarizer::new(GraphSummaryConfig {
674            include_stats: false,
675            ..Default::default()
676        });
677        let summary = summarizer.summarize(&sample_subgraph());
678        assert!(summary.structural_stats.is_none());
679    }
680
681    #[test]
682    fn test_no_communities() {
683        let mut summarizer = GraphSummarizer::new(GraphSummaryConfig {
684            include_communities: false,
685            ..Default::default()
686        });
687        let summary = summarizer.summarize(&sample_subgraph());
688        assert!(summary.communities.is_empty());
689    }
690
691    #[test]
692    fn test_shorten_uri_slash() {
693        assert_eq!(shorten_uri("http://ex.org/Alice"), "Alice");
694    }
695
696    #[test]
697    fn test_shorten_uri_hash() {
698        assert_eq!(shorten_uri("http://ex.org#name"), "name");
699    }
700
701    #[test]
702    fn test_stats_tracking() {
703        let mut summarizer = GraphSummarizer::with_defaults();
704        summarizer.summarize(&sample_subgraph());
705        assert_eq!(summarizer.stats().graphs_summarized, 1);
706        assert_eq!(summarizer.stats().total_triples_processed, 5);
707    }
708
709    #[test]
710    fn test_config_serialization() {
711        let config = GraphSummaryConfig::default();
712        let json = serde_json::to_string(&config).expect("serialize failed");
713        assert!(json.contains("max_entities"));
714    }
715
716    #[test]
717    fn test_summary_serialization() {
718        let mut summarizer = GraphSummarizer::with_defaults();
719        let summary = summarizer.summarize(&sample_subgraph());
720        let json = serde_json::to_string(&summary).expect("serialize failed");
721        assert!(json.contains("text"));
722    }
723
724    #[test]
725    fn test_triple_equality() {
726        let t1 = Triple::new("A", "knows", "B");
727        let t2 = Triple::new("A", "knows", "B");
728        assert_eq!(t1, t2);
729    }
730
731    #[test]
732    fn test_entity_summary_outgoing() {
733        let mut summarizer = GraphSummarizer::with_defaults();
734        let summary = summarizer.summarize(&sample_subgraph());
735        let alice = summary
736            .hub_entities
737            .iter()
738            .find(|e| e.label == "Alice")
739            .expect("Alice should be a hub");
740        assert!(!alice.outgoing_types.is_empty());
741    }
742
743    #[test]
744    fn test_large_subgraph() {
745        let mut triples = Vec::new();
746        for i in 0..100 {
747            triples.push(Triple::new(
748                &format!("http://ex.org/e{i}"),
749                "http://ex.org/rel",
750                &format!("http://ex.org/e{}", (i + 1) % 100),
751            ));
752        }
753        let mut summarizer = GraphSummarizer::with_defaults();
754        let summary = summarizer.summarize(&Subgraph::new(triples));
755        assert_eq!(summary.triple_count, 100);
756        assert!(summary.hub_entities.len() <= 20);
757    }
758
759    #[test]
760    fn test_relationship_types_count() {
761        let mut summarizer = GraphSummarizer::with_defaults();
762        let summary = summarizer.summarize(&sample_subgraph());
763        assert_eq!(summary.relationship_types, 3);
764    }
765
766    #[test]
767    fn test_density_calculation() {
768        let mut summarizer = GraphSummarizer::with_defaults();
769        let sg = Subgraph::new(vec![Triple::new("A", "r", "B"), Triple::new("B", "r", "A")]);
770        let summary = summarizer.summarize(&sg);
771        let stats = summary.structural_stats.expect("should have stats");
772        assert!(stats.density > 0.0 && stats.density <= 1.0);
773    }
774
775    #[test]
776    fn test_community_hub() {
777        let mut summarizer = GraphSummarizer::with_defaults();
778        let summary = summarizer.summarize(&sample_subgraph());
779        for community in &summary.communities {
780            assert!(!community.hub.is_empty());
781        }
782    }
783}
oxirs_graphrag/graph_summarization.rs

oxirs_graphrag/
graph_summarization.rs
