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/
naive-bayes.sql
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/
naive-bayes.sql
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\qecho =================================================================
\qecho === Running: Naive-Bayes Classification =========================
\qecho =================================================================
\qecho
\qecho === Refresh table: bayes ========================================
SET client_min_messages = error;
DROP TABLE IF EXISTS bayes CASCADE;
DROP TABLE IF EXISTS toclassify CASCADE;
CREATE TABLE bayes
(
id integer NOT NULL,
class INTEGER,
attributes INTEGER[],
CONSTRAINT pk_bayes PRIMARY KEY (id)
);
COPY bayes (id, class, attributes) FROM stdin;
1 1 {1, 2, 3}
3 1 {1, 4, 3}
5 2 {0, 2, 2}
2 1 {1, 2, 1}
4 2 {1, 2, 2}
6 2 {0, 1, 3}
\.
\qecho === Show training data ==========================================
SELECT * FROM bayes;
\qecho === Refresh table: toclassify ===================================
CREATE TABLE toclassify
(
id SERIAL NOT NULL,
attributes INTEGER[],
CONSTRAINT pk_toclassify PRIMARY KEY (id)
);
COPY toclassify (attributes) FROM stdin;
{0, 2, 1}
{1, 2, 3}
\.
\qecho === Show Data we want to run Naive Bayes classification on ======
SELECT * FROM toclassify;
\qecho === Precompute feature probabilities and class priors ===========
DROP TABLE IF EXISTS nb_class_priors CASCADE;
DROP TABLE IF EXISTS nb_feature_probs CASCADE;
SELECT madlib.create_nb_prepared_data_tables(
'bayes', 'class', 'attributes', 3,
'nb_feature_probs', 'nb_class_priors');
\qecho === Show feature probabilities and class priors =================
SELECT * FROM nb_feature_probs ORDER BY class, attr, value;
SELECT * FROM nb_class_priors ORDER BY class;
\qecho === Run Naive Bayes =============================================
DROP VIEW IF EXISTS nb_classify_view_fast;
SELECT madlib.create_nb_classify_view(
'nb_feature_probs', 'nb_class_priors',
'toclassify', 'id', 'attributes', 3,
'nb_classify_view_fast');
SELECT * from nb_classify_view_fast;
\qecho === Look at the probabilities for each class
\qecho === (Note we use Laplacian Smoothing):
DROP VIEW IF EXISTS nb_probs_view_fast;
SELECT madlib.create_nb_probs_view(
'nb_feature_probs', 'nb_class_priors',
'toclassify', 'id', 'attributes', 3,
'nb_probs_view_fast');
SELECT * FROM nb_probs_view_fast;
RESET client_min_messages;