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LensKit 2026.3.0b1.dev215+g1b81c620 documentation - Home LensKit 2026.3.0b1.dev215+g1b81c620 documentation - Home
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  • User Guide
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Core

  • lenskit
  • lenskit.data
    • lenskit.data.accum
      • lenskit.data.accum.Accumulator
      • lenskit.data.accum.AccumulatorFactory
      • lenskit.data.accum.ValueStatAccumulator
      • lenskit.data.accum.ValueStatistics
    • lenskit.data.amazon
    • lenskit.data.matrix
      • lenskit.data.matrix.CSRStructure
      • lenskit.data.matrix.COOStructure
      • lenskit.data.matrix.SparseIndexType
      • lenskit.data.matrix.SparseIndexListType
      • lenskit.data.matrix.SparseRowType
      • lenskit.data.matrix.SparseRowArray
    • lenskit.data.movielens
    • lenskit.data.msweb
    • lenskit.data.repr
      • lenskit.data.repr.HasObjectRepr
      • lenskit.data.repr.ReprWriter
      • lenskit.data.repr.ReprIndenter
      • lenskit.data.repr.ObjectRepr
    • lenskit.data.schema
      • lenskit.data.schema.AllowableTroolean
      • lenskit.data.schema.AttrLayout
      • lenskit.data.schema.DataSchema
      • lenskit.data.schema.EntitySchema
      • lenskit.data.schema.RelationshipSchema
      • lenskit.data.schema.ColumnSpec
    • lenskit.data.sources
      • lenskit.data.sources.amazon
      • lenskit.data.sources.movielens
        • lenskit.data.sources.movielens.MLData
        • lenskit.data.sources.movielens.ML100KLoader
        • lenskit.data.sources.movielens.MLMLoader
        • lenskit.data.sources.movielens.MLModernLoader
      • lenskit.data.sources.msweb
      • lenskit.data.sources.steam
    • lenskit.data.types
      • lenskit.data.types.AliasedColumn
      • lenskit.data.types.UIPair
      • lenskit.data.types.Extent
    • lenskit.data.EntityAttribute
    • lenskit.data.BatchedRange
    • lenskit.data.DatasetBuilder
    • lenskit.data.ItemListCollection
    • lenskit.data.ItemListCollector
    • lenskit.data.ListILC
    • lenskit.data.MutableItemListCollection
    • lenskit.data.QueryIDKey
    • lenskit.data.UserIDKey
    • lenskit.data.DataContainer
    • lenskit.data.Dataset
    • lenskit.data.EntitySet
    • lenskit.data.ItemList
    • lenskit.data.RecQuery
    • lenskit.data.MatrixRelationshipSet
    • lenskit.data.RelationshipSet
    • lenskit.data.Vocabulary
  • lenskit.pipeline
    • lenskit.pipeline.components
      • lenskit.pipeline.components.ComponentInput
      • lenskit.pipeline.components.ComponentConstructor
      • lenskit.pipeline.components.Component
      • lenskit.pipeline.components.PlaceholderConfig
      • lenskit.pipeline.components.Placeholder
    • lenskit.pipeline.config
    • lenskit.pipeline.nodes
      • lenskit.pipeline.nodes.Node
      • lenskit.pipeline.nodes.InputNode
      • lenskit.pipeline.nodes.LiteralNode
      • lenskit.pipeline.nodes.ComponentNode
      • lenskit.pipeline.nodes.ComponentConstructorNode
      • lenskit.pipeline.nodes.ComponentInstanceNode
    • lenskit.pipeline.PipelineBuilder
    • lenskit.pipeline.PipelineCache
    • lenskit.pipeline.RecPipelineBuilder
    • lenskit.pipeline.MermaidDiagrammer
    • lenskit.pipeline.ComponentInputHook
    • lenskit.pipeline.Pipeline
    • lenskit.pipeline.PipelineProfiler
    • lenskit.pipeline.ProfileSink
    • lenskit.pipeline.PipelineState
  • lenskit.operations
  • lenskit.diagnostics
    • lenskit.diagnostics.DataWarning
    • lenskit.diagnostics.DataError
    • lenskit.diagnostics.FieldError
    • lenskit.diagnostics.ConfigWarning
    • lenskit.diagnostics.TypecheckWarning
    • lenskit.diagnostics.PipelineError
    • lenskit.diagnostics.PipelineWarning
  • lenskit.training
    • lenskit.training.TrainingOptions
    • lenskit.training.Trainable
    • lenskit.training.UsesTrainer
    • lenskit.training.ModelTrainer
  • lenskit.config
    • lenskit.config.common
      • lenskit.config.common.EmbeddingSizeMixin

Components

  • lenskit.als
    • lenskit.als.ALSBase
    • lenskit.als.ALSConfig
    • lenskit.als.BiasedMFConfig
    • lenskit.als.BiasedMFScorer
    • lenskit.als.ImplicitMFConfig
    • lenskit.als.ImplicitMFScorer
  • lenskit.basic
    • lenskit.basic.bias
      • lenskit.basic.bias.BiasModel
      • lenskit.basic.bias.BiasConfig
      • lenskit.basic.bias.BiasScorer
    • lenskit.basic.candidates
      • lenskit.basic.candidates.TrainingItemsCandidateConfig
      • lenskit.basic.candidates.TrainingItemsCandidateSelector
    • lenskit.basic.composite
      • lenskit.basic.composite.FallbackScorer
    • lenskit.basic.history
      • lenskit.basic.history.LookupConfig
      • lenskit.basic.history.UserTrainingHistoryLookup
      • lenskit.basic.history.KnownRatingConfig
      • lenskit.basic.history.KnownRatingScorer
    • lenskit.basic.popularity
      • lenskit.basic.popularity.PopConfig
      • lenskit.basic.popularity.PopScorer
      • lenskit.basic.popularity.TimeBoundedPopConfig
      • lenskit.basic.popularity.TimeBoundedPopScore
    • lenskit.basic.random
      • lenskit.basic.random.RandomConfig
      • lenskit.basic.random.RandomSelector
    • lenskit.basic.topn
      • lenskit.basic.topn.TopNConfig
      • lenskit.basic.topn.TopNRanker
  • lenskit.flexmf
    • lenskit.flexmf.FlexMFConfigBase
    • lenskit.flexmf.FlexMFScorerBase
    • lenskit.flexmf.FlexMFExplicitConfig
    • lenskit.flexmf.FlexMFExplicitScorer
    • lenskit.flexmf.FlexMFImplicitConfig
    • lenskit.flexmf.FlexMFImplicitScorer
  • lenskit.funksvd
    • lenskit.funksvd.FunkSVDConfig
    • lenskit.funksvd.FunkSVDTrainingParams
    • lenskit.funksvd.FunkSVDTrainingData
    • lenskit.funksvd.FunkSVDScorer
  • lenskit.knn
    • lenskit.knn.association
      • lenskit.knn.association.AssociationConfig
      • lenskit.knn.association.AssociationScorer
    • lenskit.knn.ease
      • lenskit.knn.ease.EASEConfig
      • lenskit.knn.ease.EASEScorer
    • lenskit.knn.item
      • lenskit.knn.item.ItemKNNConfig
      • lenskit.knn.item.ItemKNNScorer
    • lenskit.knn.slim
      • lenskit.knn.slim.SLIMConfig
      • lenskit.knn.slim.SLIMScorer
    • lenskit.knn.user
      • lenskit.knn.user.UserKNNConfig
      • lenskit.knn.user.UserKNNScorer
  • lenskit.sklearn
    • lenskit.sklearn.nmf
      • lenskit.sklearn.nmf.NMFConfig
      • lenskit.sklearn.nmf.NMFScorer
    • lenskit.sklearn.svd
      • lenskit.sklearn.svd.BiasedSVDConfig
      • lenskit.sklearn.svd.BiasedSVDScorer
  • lenskit.stochastic
    • lenskit.stochastic.StochasticTopNConfig
    • lenskit.stochastic.StochasticTopNRanker

Evaluation

  • lenskit.batch
    • lenskit.batch.BatchRecRequest
    • lenskit.batch.TestRequestAdapter
    • lenskit.batch.BatchResultRow
    • lenskit.batch.BatchResults
    • lenskit.batch.BatchPipelineRunner
    • lenskit.batch.InvocationSpec
  • lenskit.metrics
    • lenskit.metrics.basic
      • lenskit.metrics.basic.ListLength
      • lenskit.metrics.basic.TestItemCount
    • lenskit.metrics.bulk
      • lenskit.metrics.bulk.RunAnalysisResult
      • lenskit.metrics.bulk.RunAnalysis
    • lenskit.metrics.predict
      • lenskit.metrics.predict.PredictMetric
      • lenskit.metrics.predict.RMSE
      • lenskit.metrics.predict.MAE
      • lenskit.metrics.predict.AvgErrorAccumulator
    • lenskit.metrics.ranking
      • lenskit.metrics.ranking.RankingMetricBase
      • lenskit.metrics.ranking.DCG
      • lenskit.metrics.ranking.NDCG
      • lenskit.metrics.ranking.Entropy
      • lenskit.metrics.ranking.RankBiasedEntropy
      • lenskit.metrics.ranking.ExposureGini
      • lenskit.metrics.ranking.ListGini
      • lenskit.metrics.ranking.Hit
      • lenskit.metrics.ranking.ILS
      • lenskit.metrics.ranking.AveragePrecision
      • lenskit.metrics.ranking.MeanPopRank
      • lenskit.metrics.ranking.Precision
      • lenskit.metrics.ranking.Recall
      • lenskit.metrics.ranking.RBP
      • lenskit.metrics.ranking.RecipRank
      • lenskit.metrics.ranking.GeometricRankWeight
      • lenskit.metrics.ranking.LogRankWeight
      • lenskit.metrics.ranking.RankWeight
    • lenskit.metrics.reranking
    • lenskit.metrics.ListMetric
    • lenskit.metrics.Metric
    • lenskit.metrics.MetricFunction
    • lenskit.metrics.MeasurementCollector
    • lenskit.metrics.RunMetrics
  • lenskit.splitting
    • lenskit.splitting.HoldoutMethod
    • lenskit.splitting.LastFrac
    • lenskit.splitting.LastN
    • lenskit.splitting.SampleFrac
    • lenskit.splitting.SampleN
    • lenskit.splitting.TTSplit
  • lenskit.tuning
    • lenskit.tuning.BasePipelineTuner
    • lenskit.tuning.PipelineTuner
    • lenskit.tuning.RayPipelineTuner
    • lenskit.tuning.RayTuneResults

Add-Ons

  • lenskit.implicit
    • lenskit.implicit.BaseRec
    • lenskit.implicit.ALS
    • lenskit.implicit.BPR
  • lenskit.hpf
    • lenskit.hpf.HPFConfig
    • lenskit.hpf.HPFScorer
  • lenskit.graphs
    • lenskit.graphs.lightgcn
      • lenskit.graphs.lightgcn.LightGCNConfig
      • lenskit.graphs.lightgcn.LightGCNScorer
      • lenskit.graphs.lightgcn.LightGCNTrainer
      • lenskit.graphs.lightgcn.LogisticLightGCNTrainer
      • lenskit.graphs.lightgcn.PairwiseLightGCNTrainer

Implementation Helpers

  • lenskit.lazy
    • lenskit.lazy.Lazy
  • lenskit.logging
    • lenskit.logging.multiprocess
      • lenskit.logging.multiprocess.Monitor
      • lenskit.logging.multiprocess.RecordSink
      • lenskit.logging.multiprocess.WorkerContext
      • lenskit.logging.multiprocess.WorkerLogConfig
    • lenskit.logging.progress
      • lenskit.logging.progress.Progress
    • lenskit.logging.tasks
      • lenskit.logging.tasks.TaskStatus
      • lenskit.logging.tasks.Task
    • lenskit.logging.LoggingConfig
    • lenskit.logging.ResourceMeasurement
    • lenskit.logging.Stopwatch
    • lenskit.logging.Tracer
  • lenskit.math
    • lenskit.math.solve
    • lenskit.math.sparse
  • lenskit.parallel
    • lenskit.parallel.config
    • lenskit.parallel.ray
      • lenskit.parallel.ray.TaskLimiter
    • lenskit.parallel.NestedPool
    • lenskit.parallel.AccelTask
  • lenskit.random
    • lenskit.random.RNGFactory
    • lenskit.random.FixedRNG
    • lenskit.random.DerivingRNG
  • lenskit.stats
  • lenskit.testing
    • lenskit.testing.BasicComponentTests
    • lenskit.testing.ScorerTests
    • lenskit.testing.DemoRecs
  • lenskit.torch
  • API Reference
  • lenskit.metrics
  • lenskit.metrics.basic

lenskit.metrics.basic#

Basic set statistics.

Classes#

ListLength

Report the length of the output (recommendation list or predictions).

TestItemCount

Report the number of test items.

Exported Aliases#

class lenskit.metrics.basic.ItemList#

Re-exported alias for lenskit.data.ItemList.

class lenskit.metrics.basic.ListMetric#

Re-exported alias for lenskit.metrics._base.ListMetric.

class lenskit.metrics.basic.Metric#

Re-exported alias for lenskit.metrics._base.Metric.

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  • Exported Aliases
    • lenskit.metrics.basic.ItemList
    • lenskit.metrics.basic.ListMetric
    • lenskit.metrics.basic.Metric

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© Copyright 2018–2025 Drexel University, Boise State University, and collaborators.

LensKit version 2026.3.0b1.dev215+g1b81c620.

This material is partially based upon work supported by the National Science Foundation under Grant Nos. 17-51278 and 24-15042. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation, Drexel University, or Boise State University.