Github user iyerr3 commented on a diff in the pull request:
https://github.com/apache/incubator-madlib/pull/168#discussion_r133629865
--- Diff: src/ports/postgres/modules/knn/knn.py_in ---
@@ -127,5 +124,102 @@ def knn_validate_src(schema_madlib, point_source,
point_column_name, label_colum
"Data type '{0}' is not a valid type for column '{1}'
in table '{2}'.".format(colType, id_column_name, test_source))
return k
-# ----------------------------------------------------------------------
-m4_changequote(<!`!>, <!'!>)
+
+
+
+
+def knn(schema_madlib, point_source, point_column_name, label_column_name,
+ test_source, test_column_name, id_column_name, output_table,
operation, k):
+
+ """
+ KNN function to find the K Nearest neighbours
+ Args:
+ @param schema_madlib Name of the Madlib Schema
+ @param point_source Training data table
+ @param point_column_name Name of the column with training
data points.
+ @param label_column_name Name of the column with
labels/values of training data points.
+ @param test_source Name of the table containing the
test data points.
+ @param test_column_name Name of the column with testing
data points.
+ @param id_column_name Name of the column having ids of
data points in test data table.
+ @param output_table Name of the table to store final
results.
+ @param k default: 1. Number of nearest
neighbors to consider
+
+
+ Returns:
+ VARCHAR Name of the output table.
+ """
+
+
+ oldClientMinMessages = plpy.execute("SELECT setting FROM pg_settings
WHERE name = 'client_min_messages'")[0]['setting'];
+
+ plpy.execute("SET client_min_messages TO warning");
+
+
+ k_val = knn_validate_src(schema_madlib, point_source,
point_column_name,
+ label_column_name, test_source,
+ test_column_name, id_column_name,
+ output_table, operation, k)
+
+
+ plpy.execute("SELECT
{schema_madlib}.create_schema_pg_temp()".format(schema_madlib = schema_madlib));
+
+ x_temp_table = unique_string(desp='x_temp_table')
+ y_temp_table = unique_string(desp='y_temp_table')
+ label_column_name_unique =
unique_string(desp='label_column_name_unique')
+ test_id = unique_string(desp='test_id')
+
+ convert_boolean_to_int = '';
+ if operation == 'c':
+ convert_boolean_to_int = '::INTEGER';
+
+ madlib_knn_interm = unique_string(desp='madlib_knn_interm')
+
+ plpy.execute("""DROP TABLE IF EXISTS
pg_temp.{madlib_knn_interm}""".format(**locals()));
+ plpy.execute(
+ """
+ CREATE TEMP TABLE pg_temp.{madlib_knn_interm} AS
+ SELECT *
+ FROM
+ (
+ SELECT row_number() over (partition by {test_id} order by dist)
AS r , {x_temp_table}.*
+ FROM
+ (
+ SELECT test.{id_column_name} AS {test_id} ,
{schema_madlib}.squared_dist_norm2(train.{point_column_name}
,test.{test_column_name}) AS dist, train.{label_column_name}
{convert_boolean_to_int} AS {label_column_name_unique}
+ FROM {point_source} AS train, {test_source} AS test
+ ) {x_temp_table}
+ ){y_temp_table}
+ WHERE {y_temp_table}.r <= {k_val}""".format(**locals()));
+
+ if operation == 'c':
+ plpy.execute(
+ """
+ CREATE TABLE {output_table} AS
+ SELECT {test_id} AS id, {test_column_name} ,
{schema_madlib}.mode({label_column_name_unique}) AS prediction
+ FROM pg_temp.{madlib_knn_interm} join {test_source} ON
{test_id} = {id_column_name}
+ GROUP BY {test_id} , {test_column_name}""".format(**locals()))
+
+
+ else:
+ plpy.execute(
+ """
+ CREATE TABLE {output_table} AS
+ SELECT {test_id} AS id, {test_column_name} , avg(
{label_column_name_unique} ) AS prediction
+ FROM
+ pg_temp.{madlib_knn_interm} join {test_source} on {test_id}
={id_column_name}
+ GROUP BY {test_id} , {test_column_name}
+ ORDER BY {test_id}""".format(**locals()))
+
+
+ plpy.execute("SET client_min_messages TO "+ oldClientMinMessages)
+
+ if operation == 'c':
+ returnstring = 'The classification results have been written to
output table '+ output_table;
+ else:
+ returnstring = 'The regression results have been written to output
table '+ output_table;
+
+ plpy.execute("""DROP TABLE
pg_temp.{madlib_knn_interm}""".format(**locals()));
+
+ return returnstring;
+
+
--- End diff --
In general, file contains multiple style-guide and PEP8 issues. Please
refer to [page in wiki for appropriate
style](https://cwiki.apache.org/confluence/display/MADLIB/Python+Style+Guide).
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