{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2016:KNP5QAMWVSWLCKYCZCDRQOMYUY","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"33148c280e0162da5c79625d1635841ce086d12169814f804b1c69920907058d","cross_cats_sorted":["cs.DS"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2016-07-12T03:24:53Z","title_canon_sha256":"ae96aaa8f86aa0762fb4b5cf4e9952ea5959a3edaef13dfa9db9c55cd4f5cbe2"},"schema_version":"1.0","source":{"id":"1607.03224","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1607.03224","created_at":"2026-05-18T00:43:18Z"},{"alias_kind":"arxiv_version","alias_value":"1607.03224v2","created_at":"2026-05-18T00:43:18Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1607.03224","created_at":"2026-05-18T00:43:18Z"},{"alias_kind":"pith_short_12","alias_value":"KNP5QAMWVSWL","created_at":"2026-05-18T12:30:25Z"},{"alias_kind":"pith_short_16","alias_value":"KNP5QAMWVSWLCKYC","created_at":"2026-05-18T12:30:25Z"},{"alias_kind":"pith_short_8","alias_value":"KNP5QAMW","created_at":"2026-05-18T12:30:25Z"}],"graph_snapshots":[{"event_id":"sha256:90cbbf9f954e5b1b07e6b4bd1f7cf68ed27f8a29f89b66051a7fd9541fa6d2a0","target":"graph","created_at":"2026-05-18T00:43:18Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"paper":{"abstract_excerpt":"We describe a simple and fast algorithm for identifying friends-of-friends features and prove its correctness. The algorithm avoids unnecessary expensive neighbor queries, uses minimal memory overhead, and rejects slowdown in high over-density regions. We define our algorithm formally based on pair enumeration, a problem that has been heavily studied in fast 2-point correlation codes and our reference implementation employs a dual KD-tree correlation function code. We construct features in a hierarchical tree structure, and use a splay operation to reduce the average cost of identifying the ro","authors_text":"Chirag Modi, Yu Feng","cross_cats":["cs.DS"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2016-07-12T03:24:53Z","title":"A fast algorithm for identifying Friends-of-Friends halos"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1607.03224","kind":"arxiv","version":2},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:9c5ae8d2b4215b1a33a2c13ba3f83150abb5c65b7fc3bca28e05f9e15227606b","target":"record","created_at":"2026-05-18T00:43:18Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"33148c280e0162da5c79625d1635841ce086d12169814f804b1c69920907058d","cross_cats_sorted":["cs.DS"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2016-07-12T03:24:53Z","title_canon_sha256":"ae96aaa8f86aa0762fb4b5cf4e9952ea5959a3edaef13dfa9db9c55cd4f5cbe2"},"schema_version":"1.0","source":{"id":"1607.03224","kind":"arxiv","version":2}},"canonical_sha256":"535fd80196acacb12b02c887183998a627cd1c3033c23800ae0206fd0d05830b","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"535fd80196acacb12b02c887183998a627cd1c3033c23800ae0206fd0d05830b","first_computed_at":"2026-05-18T00:43:18.470028Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T00:43:18.470028Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"1n8hjcx/X6Bj0nWvgpnULD7cl/8ENK8pumBv0MbfiJsnQGjWLYtoC8YGfwJAgeyglOP0k0OU8YKZz8xeUlu0CA==","signature_status":"signed_v1","signed_at":"2026-05-18T00:43:18.470779Z","signed_message":"canonical_sha256_bytes"},"source_id":"1607.03224","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:9c5ae8d2b4215b1a33a2c13ba3f83150abb5c65b7fc3bca28e05f9e15227606b","sha256:90cbbf9f954e5b1b07e6b4bd1f7cf68ed27f8a29f89b66051a7fd9541fa6d2a0"],"state_sha256":"5e25ca8b1aaff8ecfa7af92ee1be705e888ef82b040989d7f2015f3a895f50e2"}