IDAX.DECTREE - Build and then prune a decision tree model

Use this stored procedure to build a decision tree model by growing and pruning a tree.

Authorization

The privileges held by the authorization ID of the statement must include the IDAX_USER role.

Syntax

IDAX.DECTREE(in parameter_string varchar(32672))

Parameter descriptions

parameter_string
Mandatory one-string parameter that contains pairs of <parameter>=<value> entries that are separated by a comma.
Data type: VARCHAR(32672)
The following list shows the parameter values:
model
Mandatory.
The name of the decision tree model that is to be built.
Data type: VARCHAR(64)
intable
Mandatory.
The name of the input table.
Data type: VARCHAR(128)
id
Mandatory.
The column of the input table that identifies a unique instance ID.
Data type: VARCHAR(128)
target
Mandatory.
The column of the input table that represents the class.
Data type: VARCHAR(128)
incolumn
Optional.
The columns of the input table that have specific properties, which are separated by a semi-colon (;).
Each column is succeeded by one or more of the following properties:
  • By type nominal (":nom", ":nominal") or by type continuous (":cont", ":continuous"). By default, numerical types are continuous, and all other types are nominal.
  • By type nominal (:nom) or by type continuous (:cont). By default, numerical types are continuous, and all other types are nominal.
  • By role id (":id"), target (":target"), input (":active", ":in", ":input") or ignore (":ignore", ":inactive").
  • By role :id, :target, :input, or :ignore.
If this parameter is not specified, all columns of the input table have default properties.
Default: none
Data type: VARCHAR(32000)
coldeftype
Optional.
The default type of the input table columns.
Allowed values are nom and cont.
Allowed values are:
  • "nom" and "nominal" for type nominal
  • "cont" and "continuous" for type continuous
If the parameter is not specified, numeric columns are continuous, and all other columns are nominal.
Default: none
Data type: VARCHAR(4)
Data type: VARCHAR(10)
coldefrole
Optional.
The default role of the input table columns.
Allowed values are input and ignore.
Allowed values are:
  • "active", "in", and "input" for role input
  • "ignore" and "inactive" for role ignore
If the parameter is not specified, all columns are input columns.
Default: input
Data type: VARCHAR(8)
colPropertiesTable
Optional.
The input table where properties of the columns of the input table are stored.
If this parameter is not specified, the column properties of the input table column properties are detected automatically.
Default: none
Data type: VARCHAR(128)
weights
Optional.
The input table that contains optional instance weights or class weights for the columns of the input table.
If this parameter is not specified, all weights have the value 1.
Default: none
Data type: VARCHAR(128)
eval
Optional.
The class impurity measure that is used for split evaluation.
Allowed values are entropy and gini.
Default: entropy
Data type: VARCHAR(8)
minimprove
Optional.
The minimum improvement of the measure that is required for split evaluation.
Default: 0.02
Minimum: 0.0
Data type: DOUBLE
minsplit
Optional.
The minimum number of instances per tree node that can be split.
Default: 50
Minimum: 2
Data type: INTEGER
maxdepth
Optional.
The maximum number of tree levels and leaves.
Default: 10
Minimum: 1
Maximum: 62
Data type: INTEGER
valtable
Optional.
The input table that contains the validation data set.
If this parameter is not specified, no pruning is done.
Default: none
Data type: VARCHAR(128)
valweights
Optional.
The input table that contains the optional instance weights or class weights for the validation data set.
Default: none
Data type: VARCHAR(128)
qmeasure
Optional.
The quality measure for pruning.
Allowed values are Acc or wAcc.
Default: Acc
Data type: VARCHAR(4)
statistics
Optional.
Indicates the statistics that are to be collected.
Allowed values are none, columns, values:n, and all.
The following conditions apply:
  • If statistics=none is specified, no statistics are collected.
  • If statistics=columns is specified, statistics on the columns of the input table are collected, for example, mean values.
  • If statistics=values:n is specified, and if n is a positive number, statistics on the columns and the column values are collected.
    Up to <n> column value statistics are collected.
    • If a nominal column contains more than <n> values, only the <n> most frequent column statistics are kept.
    • If a numeric column contains more than <n> values, the values are discretized, and the statistics are collected on the discretized values.
  • statistics=all is identical to statistics=values:100.
Default: none
Data type: VARCHAR(32)

Returned information

The number of the nodes of a decision tree as a result set.

Example

CALL IDAX.DECTREE('model=adult_dectree, intable=adult_train, id=id, target=marital_status, valtable=adult_prune');