Apriori

class hana_ml.algorithms.pal.association.Apriori(min_support, min_confidence, relational=None, min_lift=None, max_conseq=None, max_len=None, ubiquitous=None, use_prefix_tree=None, lhs_restrict=None, rhs_restrict=None, lhs_complement_rhs=None, rhs_complement_lhs=None, thread_ratio=None, timeout=None, pmml_export=None)

Apriori is a classic predictive analysis algorithm for finding association rules used in association analysis.

Parameters
min_supportfloat

User-specified minimum support(actual value).

min_confidencefloat

User-specified minimum confidence(actual value).

relationalbool, optional

Whether or not to apply relational logic in Apriori algorithm. If False, a single result table is produced; otherwise, the result table shall be split into three tables: antecedent, consequent and statistics.

Defaults to False.

min_liftfloat, optional

User-specified minimum lift.

Defaults to 0.

max_conseqint, optional

Maximum length of consequent items.

Defaults to 100.

max_lenint, optional

Total length of antecedent items and consequent items in the output.

Defaults to 5.

ubiquitousfloat, optional

Item sets whose support values are greater than this number will be ignored during frequent items mining.

Defaults to 1.0.

use_prefix_treebool, optional

Indicates whether or not to use prefix tree for saving memory.

Defaults to False.

lhs_restrictlist of str, optional(deprecated)

Specify items that are only allowed on the left-hand-side of association rules.

rhs_restrictlist of str, optional(deprecated)

Specify items that are only allowed on the right-hand-side of association rules.

lhs_complement_rhsbool, optional(deprecated)

If you use rhs_restrict to restrict some items to the left-hand-side of the association rules, you can set this parameter to True to restrict the complement items to the left-hand-side.

For example, if you have 100 items (i1, i2, ..., i100), and want to restrict i1 and i2 to the right-hand-side, and i3,i4,...,i100 to the left-hand-side, you can set the parameters similarly as follows:

...

rhs_restrict = ['i1','i2'],

lhs_complement_rhs = True,

...

Defaults to False.

rhs_complement_lhsbool, optional(deprecated)

If you use lhs_restrict to restrict some items to the left-hand-side of association rules, you can set this parameter to True to restrict the complement items to the right-hand side.

Defaults to False.

thread_numberfloat, optional

Specifies the ratio of total number of threads that can be used by this function.

The value range is from 0 to 1, where 0 means only using 1 thread, and 1 means using at most all the currently available threads.

Values outside the range will be ignored and this function heuristically determines the number of threads to use.

Defaults to 0.

timeoutint, optional

Specifies the maximum run time in seconds. The algorithm will stop running when the specified timeout is reached.

Defaults to 3600.

pmml_export{'no', 'single-row', 'multi-row'}, optional

Specify the way to export the Apriori model:

  • 'no' : do not export the model,

  • 'single-row' : export Apriori model in PMML in single row,

  • 'multi-row' : export Apriori model in PMML in multiple rows, while the minimum length of each row is 5000 characters.

Defaults to 'no'.

Examples

Input data for associate rule mining:

>>> df.collect()
    CUSTOMER   ITEM
0          2  item2
1          2  item3
2          3  item1
3          3  item2
4          3  item4
5          4  item1
6          4  item3
7          5  item2
8          5  item3
9          6  item1
10         6  item3
11         0  item1
12         0  item2
13         0  item5
14         1  item2
15         1  item4
16         7  item1
17         7  item2
18         7  item3
19         7  item5
20         8  item1
21         8  item2
22         8  item3

Set up parameters for the Apriori algorithm:

>>> ap = Apriori(min_support=0.1,
                 min_confidence=0.3,
                 relational=False,
                 min_lift=1.1,
                 max_conseq=1,
                 max_len=5,
                 ubiquitous=1.0,
                 use_prefix_tree=False,
                 thread_ratio=0,
                 timeout=3600,
                 pmml_export='single-row')

Association rule mining using Apriori algorithm for the input data, and check the results:

>>> ap.fit(data=df)
>>> ap.result_.head(5).collect()
    ANTECEDENT CONSEQUENT   SUPPORT  CONFIDENCE      LIFT
0        item5      item2  0.222222    1.000000  1.285714
1        item1      item5  0.222222    0.333333  1.500000
2        item5      item1  0.222222    1.000000  1.500000
3        item4      item2  0.222222    1.000000  1.285714
4  item2&item1      item5  0.222222    0.500000  2.250000

Apriori algorithm set up using relational logic:

>>> apr = Apriori(min_support=0.1,
                  min_confidence=0.3,
                  relational=True,
                  min_lift=1.1,
                  max_conseq=1,
                  max_len=5,
                  ubiquitous=1.0,
                  use_prefix_tree=False,
                  thread_ratio=0,
                  timeout=3600,
                  pmml_export='single-row')

Again mining association rules using Apriori algorithm for the input data, and check the resulting tables:

>>> apr.antec_.head(5).collect()
   RULE_ID ANTECEDENTITEM
0        0          item5
1        1          item1
2        2          item5
3        3          item4
4        4          item2
>>> apr.conseq_.head(5).collect()
   RULE_ID CONSEQUENTITEM
0        0          item2
1        1          item5
2        2          item1
3        3          item2
4        4          item5
>>> apr.stats_.head(5).collect()
   RULE_ID   SUPPORT  CONFIDENCE      LIFT
0        0  0.222222    1.000000  1.285714
1        1  0.222222    0.333333  1.500000
2        2  0.222222    1.000000  1.500000
3        3  0.222222    1.000000  1.285714
4        4  0.222222    0.500000  2.250000
Attributes
result_DataFrame

Mined association rules and related statistics, structured as follows:

  • 1st column : antecedent(leading) items.

  • 2nd column : consequent(dependent) items.

  • 3rd column : support value.

  • 4th column : confidence value.

  • 5th column : lift value.

Available only when relational is False.

model_DataFrame

Apriori model trained from the input data, structured as follows:

  • 1st column : model ID,

  • 2nd column : model content, i.e. Apriori model in PMML format.

antec_DataFrame

Antecedent items of mined association rules, structured as follows:

  • 1st column : association rule ID,

  • 2nd column : antecedent items of the corresponding association rule.

Available only when relational is True.

conseq_DataFrame

Consequent items of mined association rules, structured as follows:

  • 1st column : association rule ID,

  • 2nd column : consequent items of the corresponding association rule.

Available only when relational is True.

stats_DataFrame

Statistics of the mined association rules, structured as follows:

  • 1st column : rule ID,

  • 2nd column : support value of the rule,

  • 3rd column : confidence value of the rule,

  • 4th column : lift value of the rule.

Available only when relational is True.

Methods

fit(data[, transaction, item, lhs_restrict, ...])

Association rule mining from the input data using FPGrowth algorithm.
fit(data, transaction=None, item=None, lhs_restrict=None, rhs_restrict=None, lhs_complement_rhs=None, rhs_complement_lhs=None)

Association rule mining from the input data using FPGrowth algorithm.

Parameters
dataDataFrame

Input data for association rule mining.

transactionstr, optional

Name of the transaction column.

Defaults to the first column if not provided.

itemstr, optional

Name of the item ID column.

Data type of item column can be INTEGER, VARCHAR or NVARCHAR.

Defaults to the last non-transaction column if not provided.

lhs_restrictlist of int/str, optional

Specify items that are only allowed on the left-hand-side of association rules.

Elements in the list should be the same type as the item column.

rhs_restrictlist of int/str, optional

Specify items that are only allowed on the right-hand-side of association rules.

Elements in the list should be the same type as the item column.

lhs_complement_rhsbool, optional

If you use rhs_restrict to restrict some items to the left-hand-side of the association rules, you can set this parameter to True to restrict the complement items to the left-hand-side. For example, if you have 100 items (i1,i2,...,i100), and want to restrict i1 and i2 to the right-hand-side, and i3, i4,..., i100 to the left-hand-side, you can set the parameters similarly as follows:

...

rhs_restrict = [i1, i2],

lhs_complement_rhs = True,

...

Defaults to False.

rhs_complement_lhsbool, optional

If you use lhs_restrict to restrict some items to the left-hand-side of association rules, you can set this parameter to True to restrict the complement items to the right-hand side.

Defaults to False.

property fit_hdbprocedure

Returns the generated hdbprocedure for fit.

property predict_hdbprocedure

Returns the generated hdbprocedure for predict.

Inherited Methods from PALBase

Besides those methods mentioned above, the Apriori class also inherits methods from PALBase class, please refer to PAL Base for more details.