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April 29, 2026 12:37
… bgl_graph_adapt_goal.md: defines requirements, scope, acceptance criteria\n for adapting BGL graphs to work with graph-v3 views and algorithms\n- bgl_graph_adapt_strategy.md: technical strategy covering CPO adaptation\n surface, iterator wrapping, property bridge, performance, and risks\n- bgl_graph_adapt_plan.md: phased implementation plan (phases 0-9) with\n file-level instructions, code sketches, and verification commands"
- Add placeholder headers: graph_adaptor.hpp, bgl_edge_iterator.hpp, property_bridge.hpp under include/graph/adaptors/bgl/ - Add tests/adaptors/CMakeLists.txt with conditional TEST_BGL_ADAPTOR option and Boost header auto-detection - Add 8 stub test files (SUCCEED() placeholders) for each adaptor phase - Wire tests/adaptors into tests/CMakeLists.txt via add_subdirectory All stub tests pass: graph3_bgl_adaptor_tests 1/1.
Implement bgl_edge_iterator — a thin wrapper that adds iterator_concept to BGL's boost::iterator_facade-based iterators, satisfying std::forward_iterator for C++20 ranges. - Conditional operator-> via requires clause (only when reference is an lvalue reference; adjacency_list returns proxy, CSR returns lvalue) - base() accessor for underlying BGL iterator Tests verify: - static_assert forward_iterator for adjacency_list and CSR wrappers - Reference type preservation from underlying BGL iterators - Runtime iteration matches boost::target() results - subrange of wrapped iterators models forward_range - CSR operator-> returns same address as &*it
Phase 2 — graph_adaptor and core ADL free functions: - graph_adaptor<BGL_Graph>: non-owning wrapper with CTAD - ADL vertices(), num_vertices(), edges() (out_edges CPO), target_id(), source_id() in namespace graph::bgl - graph_bgl_adl namespace with call_* helpers outside namespace graph to avoid CPO objects blocking ADL (C++ [basic.lookup.argdep]/3) Phase 3 — concept satisfaction: - static_assert adjacency_list<adapted_t> and index_adjacency_list<adapted_t> - Runtime vertexlist() smoke test confirms descriptor wiring is correct All 25 assertions in 15 test cases pass.
Implement property_bridge.hpp with three bridge types: - bgl_readable_property_map_fn: wraps any BGL readable property map into a graph-v3 edge_value_function/vertex_value_function callable - bgl_lvalue_property_map_fn: same but static_asserts that get() returns an lvalue reference, enabling write-through for writable property maps - edge_key_extractor: extracts BGL edge_descriptor from graph-v3 edge descriptor via *uv.value() - make_bgl_edge_weight_fn: convenience factory for edge weight maps - vertex_vector_property_fn / make_vertex_id_property_fn: wraps std::vector<T>& into a (const G&, vertex_id_t) -> T& function for Dijkstra distance and predecessor storage Tests verify: - Readable map reads correct weights from BGL bundled properties - Integration with incidence(g, u, evf) view - Lvalue write-through propagates to underlying BGL graph - Vector distance and predecessor storage round-trips correctly - static_assert edge_value_function and basic_edge_weight_function All 34 assertions in 20 test cases pass.
Tests vertexlist, incidence, neighbors, edgelist, and incidence-with-weight views on a directed adjacency_list<vecS,vecS,directedS> wrapped in graph_adaptor.
Two test cases on directed adjacency_list wrapped in graph_adaptor: - CLRS 5-vertex graph (correct shortest paths 0→3:5 via 0→4→3) - 4-vertex sanity-check graph Fixes incorrect expected values for dist[3] and pred[3] that had assumed the 0→2→1→3=9 path rather than the shorter 0→4→3=5 path.
graph_adaptor.hpp: - Add call_in_edges() helpers in graph_bgl_adl namespace - Add in_edges(graph_adaptor<G>, u) ADL functions (mutable + const) constrained on traversal_category convertible to bidirectional_graph_tag (covers both bidirectionalS and undirectedS) test_bgl_bidirectional.cpp: - static_assert bidirectional_adjacency_list<adapted_bidir_t> - static_assert index_bidirectional_adjacency_list<adapted_bidir_t> - static_assert bidirectional_adjacency_list<adapted_undir_t> - in_edges correctness test for bidirectionalS (source/target IDs) - dijkstra on bidirectionalS - in_edges == out_edges degree test for undirectedS - edgelist view on undirectedS (10 directed entries, 5 unique edges) - dijkstra on undirectedS cross-checked against BGL's own dijkstra
Bug fix (affects all graph types): - graph_adaptor.hpp: target_id/source_id now copy *uv.value() into a local variable instead of binding const& to it. CSR's csr_out_edge_iterator dereferences to a reference to its own m_edge member, so uv.value() (a temporary iterator copy) was producing a dangling reference. - property_bridge.hpp: edge_key_extractor::operator() changed from decltype(auto) to auto to likewise avoid returning a dangling reference to a temporary iterator member. test_bgl_csr.cpp: - static_assert index_adjacency_list<adapted_csr_t> - vertexlist view (5 vertices) - incidence view (out-edge target sets for vertices 0 and 2) - edgelist view (all 9 edges, sorted and compared) - dijkstra_shortest_paths with hand-verified CLRS distances - dijkstra cross-check against BGL's own dijkstra_shortest_paths
Implements graph::adaptors::filtered_graph<G, VertexPredicate, EdgePredicate>, a non-owning adaptor that filters vertices and edges during traversal. Design: - filtered_graph delegates begin()/end()/size()/operator[] to the underlying graph so it satisfies forward_range (CPO _has_inner_value_pattern for vertices) - edges(fg, u) ADL function returns subrange<filtering_iterator<...>> with self-contained predicate — avoids std::views::filter iterator dangling issue (filter_view iterators hold a back-pointer to their parent view) - filtering_iterator stores predicate in std::optional with custom copy/move assignment (lambdas are not assignable) to satisfy semiregular constraint - keep_all sentinel predicate accepts everything (zero overhead via [[no_unique_address]]) - filtered_vertices(fg) convenience function for lazy filtered vertex iteration Tests: 5 test cases covering keep_all passthrough, vertex predicate, edge predicate, filtered_vertices, and a Dijkstra placeholder. All 4849 tests pass.
I/O subsystem (include/graph/io/): - dot.hpp: write_dot()/read_dot() with std::format-based auto-labeling - graphml.hpp: write_graphml()/read_graphml() lightweight XML handling - json.hpp: write_json()/read_json() self-contained JGF-inspired format - detail/common.hpp: shared concepts (formattable, has_vertex_value, has_edge_value) - io.hpp: umbrella header Generators (include/graph/generators/): - erdos_renyi, barabasi_albert, grid, path generators - Extracted from benchmark fixtures to public headers Tests: 19 I/O tests + 6 generator tests (4874 total, all passing) Updated bgl_migration_strategy.md to reflect implemented status.
New user guides: - docs/user-guide/generators.md — path, grid, Erdős–Rényi, Barabási–Albert - docs/user-guide/io.md — DOT, GraphML, JSON read/write with examples Updated: - README.md — highlights, feature table, test count (4874) - docs/index.md — added I/O and generators links - docs/getting-started.md — next steps links - docs/status/metrics.md — added generator/IO counts, updated test count - docs/status/implementation_matrix.md — added Generators, I/O sections, updated umbrella headers and namespace tables
New files: - examples/bgl_adaptor_example.cpp — end-to-end Dijkstra on BGL graph - docs/user-guide/bgl-adaptor.md — user guide (quick start, property bridging, supported types, API reference, limitations) Updated: - examples/CMakeLists.txt — conditionally build BGL example - docs/index.md — added BGL adaptor guide link - agents/bgl_migration_strategy.md — Section 12 references library adaptor - agents/bgl_graph_adapt_plan.md — all phases marked complete
- Add bgl_keyed_vertex_iterator adaptor that wraps BGL void* iterators and yields pair<VD, monostate>, satisfying graph-v3's keyed_vertex_type concept so vertex_descriptor_view can be constructed - Alias bgl_vertex_range to a sized std::ranges::subrange over the adaptor - Add has_integral_vertex_id_v trait; vertices() uses if constexpr to return an iota range for vecS or a bgl_vertex_range for non-vecS - Generalize make_vertex_map_property_fn / vertex_map_property_fn to accept any associative container (map, unordered_map, etc.) - Add 11 test cases covering listS and setS: vertex iteration, edges, target_id, source_id, vertex_map_property_fn, and edge weights - Update bgl-adaptor.md: listS/setS now supported; add Non-vecS section with map storage guidance; update Known Limitations
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BGL interop improvements