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!
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