1.1 - 8.10 - LoopyBeliefPropagation Example: Equally Weighted Edges - Teradata Vantage

Teradata Vantage™ - Machine Learning Engine Analytic Function Reference

Product
Teradata Vantage
Release Number
1.1
8.10
Release Date
October 2019
Content Type
Programming Reference
Publication ID
B700-4003-079K
Language
English (United States)

In this example, the probability of hepatitis depends on all symptoms equally; therefore, the Edges table does not include edge weights.

Input

Vertices: lbp_vertices
id vertex
1 Jaundice
2 Internal bleeding
3 Loss of appetite
4 Fatigue
5 Fever
6 Dark urine
7 Stupor
8 Nausea/vomiting
9 Hepatitis
Edges: lbp_edges
id source target
1 Jaundice Hepatitis
2 Internal bleeding Hepatitis
3 Loss of appetite Hepatitis
4 Fatigue Hepatitis
5 Fever Hepatitis
6 Dark urine Hepatitis
7 Stupor Hepatitis
8 Nausea/vomiting Hepatitis

In the ObservationTable, 't' means that the symptom is present and 'f' means that it is absent.

ObservationTable: lbp_observation
id vertex obs
1 Jaundice t
2 Internal bleeding t
3 Loss of appetite t
4 Fatigue t
5 Fever f
6 Dark urine t
7 Stupor f
8 Nausea/vomiting f

SQL Call

SELECT * FROM LoopyBeliefPropagation (
  ON lbp_edges AS Edges PARTITION BY source
  ON lbp_vertices AS Vertices PARTITION BY vertex
  ON lbp_observation AS ObservationTable PARTITION BY vertex
  USING
  TargetKey ('target')
  ObservationColumn ('obs')
  Accumulate ('vertex')
  MaxIterNum (20)
  StopThreshold (1E-10)
) AS dt ORDER BY vertex;

Output

In the output table, 1 means that the symptom is present and 0 means that it is absent. Five of the eight symptoms are present, so the conditional probability of hepatitis is 5/8 (0.625).

 vertex            prob_true 
 ----------------- --------- 
 dark urine              1.0
 fatigue                 1.0
 fever                   0.0
 hepatitis             0.625
 internal bleeding       1.0
 jaundice                1.0
 loss of appetite        1.0
 nausea/vomiting         0.0
 stupor                  0.0

Download a zip file of all examples and a SQL script file that creates their input tables from the attachment in the left sidebar.