lenskit.metrics.basic.UniqueItemCount#

class lenskit.metrics.basic.UniqueItemCount#

Bases: lenskit.metrics.Metric[lenskit.data.types.IDSequence, int]

Count the number of unique items in the recommendation lists.

Stability:
Caller (see Stability Levels).
measure_list(recs, test)#

Compute measurements for a single list.

Returns:

  • A float for simple metrics

  • Intermediate data for decomposed metrics

  • A dict mapping metric names to values for multi-metric classes

Parameters:
Return type:

lenskit.data.types.IDSequence

create_accumulator()#

Creaet an accumulator to aggregate per-list measurements into summary metrics.

Each result from measure_list() is passed to Accumulator.add().