tech.tablesaw.api.ml.association

Class FrequentItemset

java.lang.Object

tech.tablesaw.api.ml.association.FrequentItemset

public class FrequentItemset
extends Object

An unsupervised data mining technique for finding things that 'are found together' frequently. We call the things 'items', and the groups they form baskets, transactions, or just 'sets'

Each basket consists of a set of items (an itemset). A set (or subset) of items that appears in many baskets is considered 'frequent'.

Constructor Summary

Constructors

Constructor and Description
FrequentItemset(IntColumn sets, CategoryColumn items, double support)
FrequentItemset(IntColumn sets, IntColumn items, double supportThreshold) Constructs and returns a frequent itemset model
FrequentItemset(ShortColumn sets, CategoryColumn items, double support)
FrequentItemset(ShortColumn sets, ShortColumn items, double support)

Method Summary

Modifier and Type	Method and Description
it.unimi.dsi.fastutil.objects.Object2DoubleOpenHashMap<it.unimi.dsi.fastutil.ints.IntRBTreeSet>	confidenceMap() Returns a map of associations and their confidence, where confidence is support for the itemset (that is, the number of times it appears in the input data) divided by the total number of sets (i.e., the percentage of input sets where it appears.
it.unimi.dsi.fastutil.objects.Object2DoubleOpenHashMap<it.unimi.dsi.fastutil.ints.IntRBTreeSet>	confidenceMap(double supportThreshold) Returns a map of associations and their confidence, where confidence is support for the itemset (that is, the number of times it appears in the input data) divided by the total number of sets (i.e., the percentage of input sets where it appears.
List<smile.association.ItemSet>	learn() Returns a list of ItemSet objects, where each itemset consists of a list of the items that were found together, plus the raw support for the itemset: the number of sets in which the combination appeared in the data given to the model
it.unimi.dsi.fastutil.objects.Object2IntOpenHashMap<int[]>	supportMap() Returns a map of discovered ItemSets and their support, where the support is the number of times the combination appears in the input data
it.unimi.dsi.fastutil.objects.Object2DoubleOpenHashMap<int[]>	supportMap(int supportThreshold) Returns a map of discovered ItemSets and their support, where the support is the number of times the combination appears in the input data.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FrequentItemset

public FrequentItemset(IntColumn sets,
                       IntColumn items,
                       double supportThreshold)

Constructs and returns a frequent itemset model

Parameters:

sets -

items -

supportThreshold - the minimum support required to be included

FrequentItemset

public FrequentItemset(IntColumn sets,
                       CategoryColumn items,
                       double support)

FrequentItemset

public FrequentItemset(ShortColumn sets,
                       CategoryColumn items,
                       double support)

FrequentItemset

public FrequentItemset(ShortColumn sets,
                       ShortColumn items,
                       double support)

Method Detail

learn

public List<smile.association.ItemSet> learn()

Returns a list of ItemSet objects, where each itemset consists of a list of the items that were found together, plus the raw support for the itemset: the number of sets in which the combination appeared in the data given to the model

supportMap

public it.unimi.dsi.fastutil.objects.Object2IntOpenHashMap<int[]> supportMap()

Returns a map of discovered ItemSets and their support, where the support is the number of times the combination appears in the input data

supportMap

public it.unimi.dsi.fastutil.objects.Object2DoubleOpenHashMap<int[]> supportMap(int supportThreshold)

Returns a map of discovered ItemSets and their support, where the support is the number of times the combination appears in the input data. The map returned contains only those items whose support is greater than the given supportThreshold

confidenceMap

public it.unimi.dsi.fastutil.objects.Object2DoubleOpenHashMap<it.unimi.dsi.fastutil.ints.IntRBTreeSet> confidenceMap()

Returns a map of associations and their confidence, where confidence is support for the itemset (that is, the number of times it appears in the input data) divided by the total number of sets (i.e., the percentage of input sets where it appears.

confidenceMap

public it.unimi.dsi.fastutil.objects.Object2DoubleOpenHashMap<it.unimi.dsi.fastutil.ints.IntRBTreeSet> confidenceMap(double supportThreshold)

Returns a map of associations and their confidence, where confidence is support for the itemset (that is, the number of times it appears in the input data) divided by the total number of sets (i.e., the percentage of input sets where it appears.

The map returned includes only those itemsets for which the confidence is above the given threshold