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`gsp_pattern_miner`
=====

GSP sequential pattern miner for sequence datasets. The library depends
on the `sequential_pattern_mining_protocols` support library,
implements the generic `pattern_miner_protocol` defined in the
`pattern_mining_protocols` core library, and mines frequent sequential
patterns using prefix-indexed candidate joins, pruning candidates whose
immediate subpatterns are not all frequent, and counting singleton and
candidate supports in batched horizontal dataset scans.

Requires a dataset implementing `sequence_dataset_protocol` with sequences
represented as ordered lists of canonical sorted itemsets over a declared
item domain.


API documentation
-----------------

Open the [../../apis/library_index.html#gsp_pattern_miner](../../apis/library_index.html#gsp_pattern_miner)
link in a web browser.


Loading
-------

To load this library, load the `loader.lgt` file:

	| ?- logtalk_load(gsp_pattern_miner(loader)).


Testing
-------

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

	| ?- logtalk_load(gsp_pattern_miner(tester)).


Features
--------

- **Level-Wise Mining**: Builds longer frequent sequences by extending the current frequent level.
- **Join-Based Candidates**: Generates candidate sequences by joining compatible frequent patterns from the previous level.
- **Support-Pruned Candidates**: Prunes candidates whose immediate subpatterns are not all frequent.
- **Batched Horizontal Support Counting**: Counts singleton and candidate supports using horizontal scans over the sequence database at each level.
- **Canonical Sequences**: Validates that itemsets are sorted, duplicate-free, non-empty, and restricted to declared items.
- **Flexible Support Thresholds**: Supports relative minimum support and absolute minimum support count.
- **Model Export**: Mined pattern collections can be exported as predicate clauses or written to a file.


Options
-------

The `mine/3` predicate accepts the following options:

- `minimum_support/1`: Relative minimum support threshold in the interval `]0.0, 1.0]`. The default is `0.5`.
- `minimum_support_count/1`: Absolute minimum support count. When both support options are provided, this option takes precedence.
- `maximum_pattern_length/1`: Maximum total number of items in a mined sequential pattern. The default is `1000`, effectively capped by the longest sequence in the dataset.
- `minimum_pattern_length/1`: Minimum total number of items retained in the mined result. The default is `1`.


Pattern miner representation
----------------------------

The mined pattern miner result is represented by a compound term with
the functor chosen by the implementation and arity 3. For example:

	gsp_pattern_miner(ItemDomain, Patterns, Options)

Where:

- `ItemDomain`: Canonical sorted list of declared dataset items.
- `Patterns`: List of `sequence_pattern(Pattern, SupportCount)` terms ordered first by total item count and then lexicographically.
- `Options`: Effective mining options used to mine the frequent sequential patterns.


References
----------

1. Srikant, R. and Agrawal, R. (1996) - "Mining sequential patterns: Generalizations and performance improvements".
