Github user hpandeycodeit commented on a diff in the pull request:
https://github.com/apache/madlib/pull/225#discussion_r162684994
--- Diff: src/ports/postgres/modules/knn/knn.sql_in ---
@@ -326,6 +331,39 @@ Result, with neighbors sorted from closest to furthest:
(6 rows)
</pre>
+
+-# Run KNN for classification using the
+weighted average:
+<pre class="example">
+DROP TABLE IF EXISTS knn_result_classification;
+SELECT * FROM madlib.knn(
+ 'knn_train_data', -- Table of training data
+ 'data', -- Col name of training data
+ 'id', -- Col name of id in train data
+ 'label', -- Training labels
+ 'knn_test_data', -- Table of test data
+ 'data', -- Col name of test data
+ 'id', -- Col name of id in test data
+ 'knn_result_classification', -- Output table
+ 3, -- Number of nearest neighbors
+ True, -- True to list nearest-neighbors
by id
+ 'madlib.squared_dist_norm2', -- Distance function
+ True -- For weighted average
+ );
+SELECT * FROM knn_result_classification ORDER BY id;
+</pre>
+<pre class="result">
+ id | data | prediction | k_nearest_neighbours
+----+---------+---------------------+----------------------
+ 1 | {2,1} | 2.2 | {1,2,3}
+ 2 | {2,6} | 0.425 | {3,4,5}
+ 3 | {15,40} | 0.0174339622641509 | {5,6,7}
+ 4 | {12,1} | 0.0379633360193392 | {3,4,5}
+ 5 | {2,90} | 0.00306428140577315 | {6,7,9}
+ 6 | {50,45} | 0.00214165229166379 | {6,7,8}
+(6 rows)
+</pre>
+
--- End diff --
@njayaram2,
Yeah, I got the same with lower version of postgres. I am changing this
query re-writing it, so this error will go away. Thanks!
---
