CrawfisSoftware.BasicGraphs 1.2.0

CrawfisSoftware.BasicGraphs

Small, experimental graph library used to explore alternative implementations of IGraph (and indexed variants) compared to the IGraph implementation used in the Grid project.

The intent of this repo is to keep the graph query/traversal surface (IGraph / IIndexedGraph) small and algorithm-friendly, while separating construction and mutation concerns into builder-style types. This makes it easier to reuse the same graph algorithms across multiple backing representations.

What this repo contains

Core interfaces (read-only usage)

• IGraph<N,E>: Graph API based on node labels (N) and edge labels (E). Optimized for algorithms that work with arbitrary node types.
• IEdge<N,E>: Edge view with From, To, and Value.

Mutable label-based graph

• Graph<N,E>: A simple, mutable implementation of IGraph<N,E>.
  • Nodes are added via AddNode(N).
  • Edges are added via AddEdge(from, to, edgeLabel, undirected: true).
  • Intended as a straightforward reference implementation.

Wrapper over a plain adjacency list

• SimpleGraph: An IGraph<int,int> wrapper over an external adjacency list (IList<ICollection<int>>).
  • This intentionally demonstrates a minimal backing store.
  • Does not support Parents(...) or InEdges(...) (throws) because the representation does not store that information.

Indexed graphs (algorithm-friendly)

Many graph algorithms are simpler and faster when nodes are represented by stable integer indices. This repo provides an indexed graph abstraction:

• IIndexedGraph<N,E>: Read-only API where nodes are int indices, with optional node labels (N) and edge labels (E).
• IIndexedEdge<E> / IndexedEdge<E>: Edge view using From, To indices.

Implementations:

• AdjacencyListIndexedGraph<N,E>: Immutable-ish adjacency-list based indexed graph. Optionally treats the graph as undirected.
• CompleteIndexedGraph<N,E>: Lightweight complete graph backed by functions (Func<int,N> for nodes, Func<int,int,E> for edges) rather than stored adjacency.

Construction (separate from IGraph / IIndexedGraph)

• GraphBuilder<N,E>: Incremental builder that collects nodes and edges into adjacency lists, then produces an IIndexedGraph<N,E> via GetGraph().
  • This is the main example of keeping “build/change” out of the query interface.

Notes / non-goals

• This repo is deliberately small and focused on representation experiments.
• It is not intended to be a full-featured graph framework (no algorithm suite here).
• API surface is oriented toward being consumed by the separate “Graph algorithms” repo.

Build

dotnet build