[GitHub] [madlib] fmcquillan99 edited a comment on pull request #496: DBSCAN: Add new module DBSCAN

[GitBox <gi...@apache.org>]

fmcquillan99 edited a comment on pull request #496:
URL: https://github.com/apache/madlib/pull/496#issuecomment-624228952


   (5)
   To be consistent with knn, can we please make the algorithm `brute_force` as the base.  It seems you can do `brute` but `brute_force` does not work:
   ```
   SELECT madlib.dbscan( 
   				'dbscan_train_data',	-- source table
   				'dbscan_result',		-- output table
   				'pid',					-- point id column
   				'pointsxx',				-- data point
   				 1.75,					-- epsilon
   				 4,						-- min samples
   				 'dist_norm2',	-- metric
   				'brute_force');			-- algorithm
   
   ERROR:  plpy.Error: dbscan Error: algorithm has to be one of the following: brute, kd-tree (plpython.c:5038)
   CONTEXT:  Traceback (most recent call last):
     PL/Python function "dbscan", line 21, in <module>
       return dbscan.dbscan(**globals())
     PL/Python function "dbscan", line 38, in dbscan
     PL/Python function "dbscan", line 184, in _validate_dbscan
     PL/Python function "dbscan", line 123, in _assert
   PL/Python function "dbscan"
   ```
   
   
   (6) 
   It seems the column header `points` does not work, maybe in conflicts with an internal name?
   I think it could be a common col name so we should fix this.
   ```
   SELECT madlib.dbscan( 
   				'dbscan_train_data',	-- source table
   				'dbscan_result',		-- output table
   				'pid',					-- point id column
   				'points',				-- data point
   				 1.75,					-- epsilon
   				 4,						-- min samples
   				 'dist_norm2',	-- metric
   				'brute');			-- algorithm
   
   ERROR:  plpy.SPIError: column reference "points" is ambiguous
   LINE 3:             SET points = points
                                    ^
   QUERY:  
               UPDATE dbscan_result AS t1
               SET points = points
               FROM dbscan_train_data AS t2
               WHERE t1.pid = t2.pid
           
   CONTEXT:  Traceback (most recent call last):
     PL/Python function "dbscan", line 21, in <module>
       return dbscan.dbscan(**globals())
     PL/Python function "dbscan", line 109, in dbscan
   PL/Python function "dbscan"
   ```


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