Migrating from Loom

This guide is for moving code from aysylu/loom or the net.clojars.savya/loom fork to cljgrapht.

When To Migrate

Migrate when you need JGraphT algorithms, JVM performance, or direct Java graph interop.

Do not migrate when you need ClojureScript or immutable graph values. loom graphs are immutable values. cljgrapht wraps mutable JGraphT graphs. Mutators return the graph for threading, but they change the same object in place.

Function Mapping

loom.graph / loom.alg	cljgrapht
loom.graph/graph	cljgrapht.core/graph
loom.graph/digraph	cljgrapht.core/digraph
loom.graph/weighted-graph	cljgrapht.core/weighted-graph
loom.graph/weighted-digraph	cljgrapht.core/weighted-digraph
loom.graph/nodes	cljgrapht.core/vertices
loom.graph/edges	cljgrapht.core/edges
loom.graph/successors	cljgrapht.core/successors
loom.graph/predecessors	cljgrapht.core/predecessors
loom.graph/add-nodes	cljgrapht.core/add-vertex, repeated
loom.graph/add-edges	cljgrapht.core/add-edge, repeated
loom.alg/bf-traverse	cljgrapht.algo/bfs
loom.alg/bf-path	cljgrapht.algo/shortest-path
loom.alg/dijkstra-path	cljgrapht.algo/shortest-path
loom.alg/dijkstra-path-dist	cljgrapht.algo/shortest-path or shortest-path-length
loom.alg/bellman-ford	cljgrapht.algo/bellman-ford
loom.alg/astar-path	cljgrapht.algo/astar
loom.alg/astar-dist	cljgrapht.algo/astar, then :weight
loom.alg/topsort	cljgrapht.algo/topological-sort
loom.alg/dag?	cljgrapht.algo/dag?
loom.alg/connected-components	cljgrapht.algo/connected-components
loom.alg/connected?	cljgrapht.algo/connected?
loom.alg/scc	cljgrapht.algo/strongly-connected-components
loom.alg/strongly-connected?	cljgrapht.algo/strongly-connected?
loom.alg/bipartite?	cljgrapht.algo/bipartite?
loom.alg/bipartite-sets	cljgrapht.algo/bipartite-sets
loom.alg/greedy-coloring	cljgrapht.algo/greedy-coloring
loom.alg/max-flow	cljgrapht.algo/max-flow
loom.alg/prim-mst	cljgrapht.algo/minimum-spanning-tree
loom.alg/maximal-cliques	cljgrapht.algo/maximal-cliques
loom.alg/clustering-coefficient	cljgrapht.algo/clustering-coefficient
loom.alg/loners	cljgrapht.algo/isolated-vertices
loom.alg/density	cljgrapht.algo/density
loom.alg/distinct-edges	cljgrapht.core/edges, then normalize if needed
loom.alg/isomorphism?	cljgrapht.algo/isomorphic?
loom.alg/pre-traverse	cljgrapht.algo/dfs

Beyond Loom

These cljgrapht functions expose JGraphT capabilities without direct Loom counterparts.

cljgrapht	Notes
cljgrapht.algo/bellman-ford-distances	Single-source Bellman-Ford distances.
cljgrapht.algo/all-pairs-shortest-path-length	Floyd-Warshall all-pairs shortest paths.
cljgrapht.algo/johnson-all-pairs	Johnson all-pairs shortest paths.
cljgrapht.algo/k-shortest-paths	Yen k shortest simple paths.
cljgrapht.algo/all-simple-paths	All simple directed paths between two vertices.
cljgrapht.algo/cycle?	Directed cycle detection.
cljgrapht.algo/vertices-on-cycles	Vertices participating in directed cycles.
cljgrapht.algo/simple-cycles	Directed simple cycle enumeration.
cljgrapht.algo/maximum-matching	Edmonds maximum cardinality matching.
cljgrapht.algo/maximum-weight-matching	Kolmogorov weighted matching.
cljgrapht.algo/bipartite-matching	Hopcroft-Karp bipartite matching.
cljgrapht.algo/min-cut	Minimum source/sink cut from push-relabel.
cljgrapht.algo/coloring	Selectable coloring algorithms.
cljgrapht.algo/global-clustering-coefficient	Whole-graph clustering score.
cljgrapht.algo/coreness	Core number per vertex.
cljgrapht.algo/betweenness-centrality	Betweenness centrality scores.
cljgrapht.algo/closeness-centrality	Closeness centrality scores.
cljgrapht.algo/pagerank	PageRank scores.
cljgrapht.gen/complete-graph	JGraphT complete graph generator.
cljgrapht.gen/ring-graph	JGraphT ring graph generator.
cljgrapht.gen/star-graph	JGraphT star graph generator.
cljgrapht.gen/grid-graph	JGraphT grid graph generator.
cljgrapht.gen/gnp-random-graph	Seedable Erdos-Renyi generator.
cljgrapht.gen/barabasi-albert-graph	Seedable Barabasi-Albert generator.
cljgrapht.gen/watts-strogatz-graph	Seedable Watts-Strogatz generator.
cljgrapht.io/dot	DOT export.
cljgrapht.io/read-dot	DOT import with string vertex ids.
cljgrapht.io/graphml	GraphML export.

Not Covered

Loom area	cljgrapht status	Workaround
loom.alg/post-traverse	No direct wrapper.	Use JGraphT interop directly or keep Loom for that traversal.
loom.attr	No separate attribute namespace.	Put attributes in vertex values or maintain an external map.
loom.io/view	No visualization wrapper.	Export DOT with cljgrapht.io/dot and render with Graphviz.
ClojureScript	Not supported.	Keep Loom for CLJS code.

Attribute Pattern

Loom attribute code often keeps identity and attributes separate:

(require '[loom.graph :as lg]
         '[loom.attr :as attr])

(-> (lg/graph [:a :b])
    (attr/add-attr :a :label "Alice"))

In cljgrapht, vertices can be arbitrary Clojure values. Put the attributes in the vertex value when that fits your model:

(require '[cljgrapht.core :as g])

(def alice {:id :a :label "Alice"})
(def bob {:id :b :label "Bob"})

(def gr (g/graph [[alice bob]]))

If vertex identity and attributes must change independently, keep vertices as stable ids and store attributes in a separate map.

Incremental Migration With cljgrapht.loom

cljgrapht.loom extends Loom protocols to raw JGraphT graphs. Load the namespace for side effects, then Loom algorithms can consume a cljgrapht graph:

(require '[cljgrapht.core :as g]
         '[cljgrapht.loom]
         '[loom.alg :as alg])

(def gr (g/weighted-digraph [[:a :b 1.0] [:a :c 10.0] [:b :c 1.0]]))

(alg/dijkstra-path gr :a :c)
;; => (:a :b :c)

This lets you migrate construction first, then replace Loom algorithms one call site at a time.

DFS Ordering

Loom pre-traverse visits neighbors in adjacency order. cljgrapht.algo/dfs uses JGraphT's stack-based iterator, so later neighbors can be visited first. If exact traversal order is observable in your tests, update the expected order while migrating.