Release notes for LensKit 1.2

The Git changelog and the list of closed tickets and pull requests provide more information on what has happened, including bugs that have been fixed.

• Added LenskitConfiguration class and deprecated LenskitRecommenderEngineFactory. Use LenskitRecommenderEngine.build() to build an engine from a configuration.

• Added PreferenceDomainBuilder to build preference domains.

• PreferenceDomain now uses a precision of 0 to represent continuous scales (#issue(327)); the value is still formally undefined behavior, but code which (incorrectly) depended on the precision when a domain does not have a precision may need to be corrected.

• Implemented new lenskit-groovy module to load LensKit configurations from Groovy-based configuration files. See the config package JavaDoc for information on how to use this support.

• SparseVector performance improvements, particularly for dot products.

  • Sparse vectors now expose Pointers over their entries directly, allowing pointer-based access more efficiently than with IteratorPointer.

  • Pairwise iteration in Vectors uses direct pointers.

  • Dot products now use pairs of pointers directly, rather than indirectly using pairwise iteration.