Add/line graph

.git-blame-ignore-revs

@@ -0,0 +1,7 @@
+# .git-blame-ignore-revs
+# Initial converion to uniform formatting
+ea6bcfeb71de9d1229bbd411ef9b10cac44fa795
+# Formatter v1 improvements
+5878e7be4d68b2a1c179d1367aea670db115ebb5
+# updating to Formatter v2
+f4b70cd8bbbcd43bf127bbe2acf3f7a11aef7942

.gitignore

@@ -6,11 +6,9 @@ docs/build/
 docs/site/
 benchmark/.results/*
 benchmark/.tune.jld
-benchmark/Manifest.toml
 .benchmarkci
 *.cov
-/Manifest.toml
-/docs/Manifest.toml
+Manifest.toml
 /docs/src/index.md
 /docs/src/contributing.md
 /docs/src/license.md

CHANGELOG.md

@@ -0,0 +1,84 @@
+# News
+
+We follow SemVer as most of the Julia ecosystem. Below you might see the "breaking" label even for minor version bumps -- we use it a bit more loosely to denote things that are not breaking by SemVer's definition but might cause breakage to people using internal or experimental APIs or undocumented implementation details. 
+
+## unreleased
+- `is_articulation(g, v)` for checking whether a single vertex is an articulation point
+
+
+## v1.14.0 - 2026-02-26
+- **(breaking)** `neighbors`, `inneighbors`, and `outneighbors` now return an immutable `FrozenVector` instead of `Vector`
+- Louvain community detection algorithm
+- Graph views: `ReverseView` and `UndirectedView` for directed graphs
+- New graph products: `strong_product`, `disjunctive_product`, `lexicographic_product`, `homomorphic_product`
+- `maximum_clique`, `clique_number`, `maximal_independent_sets`, `maximum_independent_set`, `independence_number`
+- `regular_tree` generator
+- `kruskal_mst` now accepts weight vectors
+- `is_planar` planarity test and `planar_maximally_filtered_graph` (PMFG) algorithm
+- `count_connected_components` for efficiently counting connected components without materializing them
+- `connected_components!` is now exported and accepts an optional `search_queue` argument to reduce allocations
+- `is_connected` optimized to avoid allocating component vectors
+
+## v1.13.0 - 2025-06-05
+- **(breaking)** Julia v1.10 (LTS) minimum version requirement
+- Non-allocating `enumerate_paths!`
+
+## v1.12.0 - 2024-09-29
+- New options for `BFSIterator`
+
+## v1.11.0 - 2024-05-05
+- DFS and BFS iterators
+- Dorogovtsev-Mendes graph generator optimization
+
+## v1.10.0 - 2024-04-05
+- Longest path algorithm for DAGs
+- All simple paths algorithm
+
+## v1.9.0 - 2023-09-28
+- Rewrite of `edit_distance` with edge costs
+- Eulerian cycles/trails for undirected graphs
+- `mincut` implementation
+- `strongly_connected_components_tarjan`
+
+## v1.8.0 - 2023-02-10
+- `newman_watts_strogatz` graph generator
+- Prufer coding for trees
+- `isdigraphical`
+
+## v1.7.0 - 2022-06-19
+- Hierarchical documentation structure
+
+## v1.6.0 - 2022-02-09
+- **(breaking)** Requires Julia >= v1.6
+- **(breaking)** `Base.zero` no longer mandatory for `AbstractGraph`
+- Simplified `AbstractGraph` interface
+
+## v1.5.0 - 2022-01-09
+- **(breaking)** `merge_vertices` now only works on subtypes of `AbstractSimpleGraph`
+- `rich_club` function
+- `induced_subgraph` with boolean indexing
+- Optional start vertex for `maximum_adjacency_search`
+
+## v1.4.0 - 2021-10-17
+- Initial release as Graphs.jl (successor to LightGraphs.jl)
+
+The _Graphs.jl_ project is a reboot of the _LightGraphs.jl_ package (archived in October 2021), which remains available on GitHub at [sbromberger/LightGraphs.jl](https://github.com/sbromberger/LightGraphs.jl). If you don't need any new features developed since the fork, you can continue to use older versions of _LightGraphs.jl_ indefinitely. New versions will be released here using the name _Graphs.jl_ instead of _LightGraphs.jl_. There was an older package also called _Graphs.jl_. The source history and versions are still available in this repository, but the current code base is unrelated to the old _Graphs.jl_ code and is derived purely from _LightGraphs.jl_. To access the history of the old _Graphs.jl_ code, you can start from [commit 9a25019](https://github.com/JuliaGraphs/Graphs.jl/commit/9a2501948053f60c630caf9d4fb257e689629041).
+
+### Transition from LightGraphs to Graphs
+
+_LightGraphs.jl_ and _Graphs.jl_ are functionally identical, still there are some steps involved making the change:
+
+- Change `LightGraphs = "093fc24a-ae57-5d10-9952-331d41423f4d"` to `Graphs = "86223c79-3864-5bf0-83f7-82e725a168b6"` in your Project.toml.
+- Update your `using` and `import` statements.
+- Update your type constraints and other references to `LightGraphs` to `Graphs`.
+- Increment your version number. Following semantic versioning, we suggest a patch release when no graphs or other `Graphs.jl`-objects can be passed through the API of your package by those depending on it, otherwise consider it a breaking release. "Passed through" entails created outside and consumed inside your package and vice versa.
+- Tag a release.
+
+### About versions
+
+- The master branch of _Graphs.jl_ is generally designed to work with versions of Julia starting from the [LTS release](https://julialang.org/downloads/#long_term_support_release) all the way to the [current stable release](https://julialang.org/downloads/#current_stable_release), except during Julia version increments as we transition to the new version.
+- Later versions: Some functionality might not work with prerelease / unstable / nightly versions of Julia. If you run into a problem, please file an issue.
+- The project was previously developed under the name _LightGraphs.jl_ and older versions of _LightGraphs.jl_ (≤ v1.3.5) must still be used with that name.
+- There was also an older package also called _Graphs.jl_ (git tags `v0.2.5` through `v0.10.3`), but the current code base here is a fork of _LightGraphs.jl_ v1.3.5.
+- All older _LightGraphs.jl_ versions are tagged using the naming scheme `lg-vX.Y.Z` rather than plain `vX.Y.Z`, which is used for old _Graphs.jl_ versions (≤ v0.10) and newer versions derived from _LightGraphs.jl_ but released with the _Graphs.jl_ name (≥ v1.4).
+- If you are using a version of Julia prior to 1.x, then you should use _LightGraphs.jl_ at `lg-v.12.*` or _Graphs.jl_ at `v0.10.3`

Project.toml

@@ -1,46 +1,33 @@
 name = "Graphs"
 uuid = "86223c79-3864-5bf0-83f7-82e725a168b6"
-version = "1.13.0"
+version = "1.14.0"
 
 [deps]
 ArnoldiMethod = "ec485272-7323-5ecc-a04f-4719b315124d"
 DataStructures = "864edb3b-99cc-5e75-8d2d-829cb0a9cfe8"
-Distributed = "8ba89e20-285c-5b6f-9357-94700520ee1b"
 Inflate = "d25df0c9-e2be-5dd7-82c8-3ad0b3e990b9"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
-SharedArrays = "1a1011a3-84de-559e-8e89-a11a2f7dc383"
 SimpleTraits = "699a6c99-e7fa-54fc-8d76-47d257e15c1d"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 
+[weakdeps]
+Distributed = "8ba89e20-285c-5b6f-9357-94700520ee1b"
+SharedArrays = "1a1011a3-84de-559e-8e89-a11a2f7dc383"
+
+[extensions]
+GraphsSharedArraysExt = "SharedArrays"
+
 [compat]
-Aqua = "0.6"
 ArnoldiMethod = "0.4"
-DataStructures = "0.17, 0.18"
-Documenter = "0.27"
+DataStructures = "0.19"
+Distributed = "1"
 Inflate = "0.1.3"
-JuliaFormatter = "1"
-SimpleTraits = "0.9"
-StableRNGs = "1"
+LinearAlgebra = "1"
+Random = "1"
+SharedArrays = "1"
+SimpleTraits = "0.9.1"
+SparseArrays = "1"
 Statistics = "1"
 julia = "1.10"
-
-[extras]
-Aqua = "4c88cf16-eb10-579e-8560-4a9242c79595"
-Base64 = "2a0f44e3-6c83-55bd-87e4-b1978d98bd5f"
-DelimitedFiles = "8bb1440f-4735-579b-a4ab-409b98df4dab"
-Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
-JET = "c3a54625-cd67-489e-a8e7-0a5a0ff4e31b"
-JuliaFormatter = "98e50ef6-434e-11e9-1051-2b60c6c9e899"
-LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
-Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
-Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
-SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
-StableRNGs = "860ef19b-820b-49d6-a774-d7a799459cd3"
-Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
-Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
-Unitful = "1986cc42-f94f-5a68-af5c-568840ba703d"
-
-[targets]
-test = ["Aqua", "Base64", "DelimitedFiles", "Documenter", "JET", "JuliaFormatter", "LinearAlgebra", "Pkg", "Random", "SparseArrays", "StableRNGs", "Statistics", "Test", "Unitful"]

README.md

@@ -68,25 +68,6 @@ It is an explicit design decision that any data not required for graph manipulat
 
 Additional functionality like advanced IO and file formats, weighted graphs, property graphs, and optimization-related functions can be found in the packages of the [JuliaGraphs organization](https://juliagraphs.org/).
 
-## Project status
+## Project history
 
-The _Graphs.jl_ project is a reboot of the _LightGraphs.jl_ package (archived in October 2021), which remains available on GitHub at [sbromberger/LightGraphs.jl](https://github.com/sbromberger/LightGraphs.jl). If you don't need any new features developed since the fork, you can continue to use older versions of _LightGraphs.jl_ indefinitely. New versions will be released here using the name _Graphs.jl_ instead of _LightGraphs.jl_. There was an older package also called _Graphs.jl_. The source history and versions are still available in this repository, but the current code base is unrelated to the old _Graphs.jl_ code and is derived purely from _LightGraphs.jl_. To access the history of the old _Graphs.jl_ code, you can start from [commit 9a25019](https://github.com/JuliaGraphs/Graphs.jl/commit/9a2501948053f60c630caf9d4fb257e689629041).
-
-### Transition from LightGraphs to Graphs
-
-_LightGraphs.jl_ and _Graphs.jl_ are functionally identical, still there are some steps involved making the change:
-
-- Change `LightGraphs = "093fc24a-ae57-5d10-9952-331d41423f4d"` to `Graphs = "86223c79-3864-5bf0-83f7-82e725a168b6"` in your Project.toml.
-- Update your `using` and `import` statements.
-- Update your type constraints and other references to `LightGraphs` to `Graphs`.
-- Increment your version number. Following semantic versioning, we suggest a patch release when no graphs or other `Graphs.jl`-objects can be passed through the API of your package by those depending on it, otherwise consider it a breaking release. "Passed through" entails created outside and consumed inside your package and vice versa.
-- Tag a release.
-
-### About versions
-
-- The master branch of _Graphs.jl_ is generally designed to work with versions of Julia starting from the [LTS release](https://julialang.org/downloads/#long_term_support_release) all the way to the [current stable release](https://julialang.org/downloads/#current_stable_release), except during Julia version increments as we transition to the new version.
-- Later versions: Some functionality might not work with prerelease / unstable / nightly versions of Julia. If you run into a problem, please file an issue.
-- The project was previously developed under the name _LightGraphs.jl_ and older versions of _LightGraphs.jl_ (≤ v1.3.5) must still be used with that name.
-- There was also an older package also called _Graphs.jl_ (git tags `v0.2.5` through `v0.10.3`), but the current code base here is a fork of _LightGraphs.jl_ v1.3.5.
-- All older _LightGraphs.jl_ versions are tagged using the naming scheme `lg-vX.Y.Z` rather than plain `vX.Y.Z`, which is used for old _Graphs.jl_ versions (≤ v0.10) and newer versions derived from _LightGraphs.jl_ but released with the _Graphs.jl_ name (≥ v1.4).
-- If you are using a version of Julia prior to 1.x, then you should use _LightGraphs.jl_ at `lg-v.12.*` or _Graphs.jl_ at `v0.10.3`
+_Graphs.jl_ is the successor to _LightGraphs.jl_ (archived October 2021); see the [CHANGELOG](CHANGELOG.md) for the full transition history.

docs/Project.toml

@@ -1,6 +1,8 @@
 [deps]
 Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
 Graphs = "86223c79-3864-5bf0-83f7-82e725a168b6"
+IGraphs = "647e90d3-2106-487c-adb4-c91fc07b96ea"
+NautyGraphs = "7509a0a4-015a-4167-b44b-0799a1a2605e"
 
 [compat]
 Documenter = "1"

docs/make.jl

@@ -1,5 +1,7 @@
 using Documenter
 using Graphs
+using IGraphs: IGraphs
+using NautyGraphs: NautyGraphs
 
 # same for contributing and license
 cp(
@@ -17,6 +19,11 @@ cp(
     normpath(@__FILE__, "../src/index.md");
     force=true,
 )
+cp(
+    normpath(@__FILE__, "../../CHANGELOG.md"),
+    normpath(@__FILE__, "../src/CHANGELOG.md");
+    force=true,
+)
 
 function get_title(markdown_file_path::AbstractString)
     first_line = open(markdown_file_path) do io
@@ -35,7 +42,11 @@ pages_files = [
         "first_steps/plotting.md",
         "first_steps/persistence.md",
     ],
-    "Ecosystem" => ["ecosystem/graphtypes.md", "ecosystem/interface.md"],
+    "Ecosystem" => [
+        "ecosystem/graphtypes.md",
+        "ecosystem/graphalgorithms.md",
+        "ecosystem/interface.md",
+    ],
     "Core API" => [
         "core_functions/core.md",
         "core_functions/interface.md",
@@ -44,6 +55,7 @@ pages_files = [
         "core_functions/persistence.md",
         "core_functions/simplegraphs_generators.md",
         "core_functions/simplegraphs.md",
+        "core_functions/wrappedgraphs.md",
     ],
     "Algorithms API" => [
         "algorithms/biconnectivity.md",
@@ -94,6 +106,7 @@ makedocs(;
         canonical="https://gdalle.github.io/Graphs.jl",
     ),
     sitename="Graphs.jl",
+    checkdocs=:public,
     doctest=false,
     expandfirst=[],
     pages=[
@@ -109,3 +122,4 @@ deploydocs(; repo="github.com/JuliaGraphs/Graphs.jl.git", target="build")
 rm(normpath(@__FILE__, "../src/contributing.md"))
 rm(normpath(@__FILE__, "../src/license.md"))
 rm(normpath(@__FILE__, "../src/index.md"))
+rm(normpath(@__FILE__, "../src/CHANGELOG.md"))

docs/src/algorithms/community.md

@@ -19,6 +19,7 @@ Pages = [
     "community/clustering.jl",
     "community/core-periphery.jl",
     "community/label_propagation.jl",
+    "community/louvain.jl",
     "community/modularity.jl",
     "community/rich_club.jl",
 ]

docs/src/algorithms/spanningtrees.md

@@ -16,6 +16,8 @@ Pages = [
     "spanningtrees/boruvka.jl",
     "spanningtrees/kruskal.jl",
     "spanningtrees/prim.jl",
+    "planarity.jl",
+    "spanningtrees/planar_maximally_filtered_graph.jl",
 ]
 
 ```

docs/src/core_functions/wrappedgraphs.md

@@ -0,0 +1,21 @@
+# Graph views formats
+
+*Graphs.jl* provides views around directed graphs. 
+`ReverseGraph` is a graph view that wraps a directed graph and reverse the direction of every edge.
+`UndirectedGraph` is a graph view that wraps a directed graph and consider every edge as undirected.
+
+## Index
+
+```@index
+Pages = ["wrappedgraphs.md"]
+```
+
+## Full docs
+
+```@autodocs
+Modules = [Graphs]
+Pages = [
+    "wrappedGraphs/graphviews.jl",
+]
+
+```

docs/src/ecosystem/graphalgorithms.md

@@ -0,0 +1,57 @@
+# Graph algorithms
+
+## Defined by Graphs.jl
+
+_Graphs.jl_ provides a number of graph algorithms, including [Cuts](@ref), [Cycles](@ref), and [Trees](@ref), among many others. The algorithms work on any graph type that conforms to the _Graphs.jl_ API.
+
+## External algorithm packages
+
+Several other packages implement additional graph algorithms:
+
+- [GraphsColoring.jl](https://github.com/JuliaGraphs/GraphsColoring.jl) provides algorithms for graph coloring, _i.e._, assigning colors to vertices such that no two neighboring vertices have the same color.
+- [GraphsFlows.jl](https://github.com/JuliaGraphs/GraphsFlows.jl) provides algorithms for graph flows.
+- [GraphsMatching.jl](https://github.com/JuliaGraphs/GraphsMatching.jl) provides algorithms for matchings on weighted graphs.
+- [GraphsOptim.jl](https://github.com/JuliaGraphs/GraphsOptim.jl) provides algorithms for graph optimization that rely on mathematical programming.
+
+## Interfaces to other graph libraries
+
+Several packages make established graph libraries written in other languages accessible from within Julia and the _Graphs.jl_ ecosystem:
+
+- [IGraphs.jl](https://github.com/JuliaGraphs/IGraphs.jl) is a thin Julia wrapper around the C graphs library [igraph](https://igraph.org).
+- [NautyGraphs.jl](https://github.com/JuliaGraphs/NautyGraphs.jl) provides graph structures compatible with the graph isomorphism library [_nauty_](https://pallini.di.uniroma1.it), allowing for efficient isomorphism checking and canonization, as well as computing the properties of graph automorphism groups.
+
+## Dispatching to algorithm implementations in external packages
+
+Apart from providing additional graph types and algorithms, many packages extend existing functions in _Graphs.jl_ with new backends. This can make it easier to use the algorithms from within _Graphs.jl_.
+
+For example, _NautyGraphs.jl_ provides a new backend for graph isomorphism calculations:
+
+```jldoctest
+julia> using Graphs, NautyGraphs
+
+julia> g = star_graph(5)
+{5, 4} undirected simple Int64 graph
+
+julia> Graphs.Experimental.has_isomorph(g, g, NautyAlg())
+true
+```
+
+Here, dispatching via `NautyAlg()` implicitly converts `g` to a _nauty_-compatible format and uses _nauty_ for the isomorphism computation.
+
+### Functions extended by IGraphs.jl
+
+A list of functions extended by _IGraphs.jl_ can be obtained with
+
+```@example
+import IGraphs
+IGraphs.igraphalg_methods()
+```
+
+### Functions extended by NautyGraphs.jl
+
+A list of functions extended by _NautyGraphs.jl_ can be obtained with
+
+```@example
+import NautyGraphs
+NautyGraphs.nautyalg_methods()
+```

docs/src/ecosystem/interface.md

@@ -5,7 +5,7 @@ This section is designed to guide developers who wish to write their own graph s
 All Graphs.jl functions rely on a standard API to function. As long as your graph structure is a subtype of [`AbstractGraph`](@ref) and implements the following API functions with the given return values, all functions within the Graphs.jl package should just work:
 
 - [`edges`](@ref)
-- [`edgetype`](@ref) (example: `edgetype(g::CustomGraph) = Graphs.SimpleEdge{eltype(g)})`)
+- [`edgetype`](@ref) (example: `edgetype(g::CustomGraph) = Graphs.SimpleEdge{eltype(g)}`)
 - [`has_edge`](@ref)
 - [`has_vertex`](@ref)
 - [`inneighbors`](@ref)

docs/src/first_steps/paths_traversal.md

@@ -10,7 +10,6 @@ Any graph traversal will traverse an edge only if it is present in the graph. Wh
 
 1. distance values for undefined edges will be ignored;
 2. any unassigned values (in sparse distance matrices) for edges that are present in the graph will be assumed to take the default value of 1.0;
-3. any zero values (in sparse/dense distance matrices) for edges that are present in the graph will instead have an implicit edge cost of 1.0.
 
 ## Graph traversal