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@wilfwilson wilfwilson released this 27 Oct 17:17
v1.5.0
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wilfwilson Wilf Wilson
GPG key ID: 4C44C7C2C8454B3B
Learn about vigilant mode.

This is a fairly major release of the Digraphs package, containing some bugfixes and several new features.

In this version, we welcome Finn Buck, Tom Conti-Leslie, Ewan Gilligan, Lea Racine, and Ben Spiers as contributors to the package.

Bugfixes

  • The edge labels of Cayley digraphs could sometimes be incorrect (Fixed by Jan De Beule in PR #452)
  • Typos in the documentation of IsDirectedTree and an error message for OnDigraphs were fixed (Wilf A. Wilson in PRs #480 and #498)

A database of one-off named graphs and digraphs, and more families of standard examples

We especially wish to highlight the greatly expanded functionality for creating digraphs that are either famous one-off examples, or are part of a family of standard examples.

In particular, Finn Buck, Lea Racine, James D. Mitchell, Marina Anagnostopoulou-Merkouri, and Ben Spiers implemented functions to construct many more families of standard examples (currently documented in Section 3.5), which were added in in PRs
#408, #409, #411, #415, #416, #417, #423, #424, #425, #445, #454, #456, and #490.

Furthermore, Reinis Cirpons, Tom Conti-Leslie, and Murray Whyte added a database of one-off named graphs and digraphs in PR #404.
These digraphs can be constructed by calling Digraph with a string of appropriate name, e.g. Digraph("brinkmann").
The available names can be accessed with the ListNamedDigraphs function.

Other new features

  • Tarjan and Lengauer's almost-linear time dominators algorithm was implemented, and is available via Dominators and DominatorTree (James D. Mitchell, Marina Anagnostopoulou-Merkouri, Samantha Harper, and Finn Buck, in PR #336)
  • MaximalCommonSubdigraph and MinimalCommonSuperdigraph were introduced (Luke Elliot, PR #361)
  • DigraphShortestPathSpanningTree was introduced (Jan De Beule and Wilf A. Wilson, in PR #363)
  • Lawler and Byskov's algorithms for chromatic number were implemented (Ewan Gilligan, PR #382)
  • Cayley digraphs now have pre-set vertex and edge labels (Jan De Beule and Wilf A. Wilson, in PR #385)
  • DigraphCycle was added as a synonym for CycleDigraph (Wilf A. Wilson, PR #441)
  • Several new digraph product operations were introduced: StrongProduct, ConormalProduct, HomomorphicProduct, and LexicographicProduct (Finn Buck, PR #460)
  • The operation IsDigraphPath was introduced (James D. Mitchell, PR #489)

Other changes

Assets 4
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