.. _library_multisets:

multisets

This library provides predicates for generating and querying multisets over lists. Multisets are unordered selections of a given length with element repetition allowed. The following categories of predicates are provided:

• Generation operations - Predicates for generating multisets.
• Ordering variants - Predicates that support an additional order argument (default or lexicographic) for controlling output order.
• Distinct-value generation - Predicates for generating multisets while deduplicating equal-valued results.
• Indexed access - Predicates for direct access to multisets at specific positions, including order-aware access.
• Counting operations - Predicates for counting multisets and distinct multisets.
• Random selection - Predicates for randomly selecting and sampling multisets and distinct multisets.
• Lexicographic stepping - Predicates for stepping to the next or previous multiset in lexicographic order.

  Dedicated arrangements, cartesian_products, combinations, permutations, derangements, partitions, and subsequences libraries are also available for focused APIs on related operations.

API documentation

Open the `../../apis/library_index.html#multisets <../../apis/library_index.html#multisets>`__ link in a web browser.

Loading

To load all entities in this library, load the loader.lgt file:

::

| ?- logtalk_load(multisets(loader)).

Testing

To test this library predicates, load the tester.lgt file:

::

| ?- logtalk_load(multisets(tester)).