I have a relation of about 50000 tuples that I want to join to itself either by using a cross operator or something similar. Then I would be doing pair wise computation of half the matrix (avoiding comparing to self and duplicate).
I was wondering what the most effective way to do this, below is some pseudo pig latin. -- About 50,000 - 70,000 entries a = LOAD 'part-r-00000.txt' USING PigStorage() AS (id:long, x:int, y:int); -- Same as a , About 50,000 - 70,000 entries b = LOAD 'part-r-00000.txt' USING PigStorage() AS (id:long, x:int, y:int); jnd = join a by id , b by id; -- filter comparisons to self and duplicates from the matrix -- end up with 50000 X (50000-1)/2 entries filter_self = filter jnd by a::id != b::id and a::id > b::id; raw = foreach filter_self generate a::id as id1, b::id as id2, TOBAG(a::x, b::y) as z; -- group pairs for comparison grpd = group raw by (id1, id2); -- calculate similarity between id1 and id2 based on a udf prjctd = foreach grpd generate flatten(group), UDF(raw.z); This e-mail message may contain privileged and/or confidential information, and is intended to be received only by persons entitled to receive such information. If you have received this e-mail in error, please notify the sender immediately. Please delete it and all attachments from any servers, hard drives or any other media. Other use of this e-mail by you is strictly prohibited. All e-mails and attachments sent and received are subject to monitoring, reading and archival by Monsanto, including its subsidiaries. The recipient of this e-mail is solely responsible for checking for the presence of "Viruses" or other "Malware". Monsanto, along with its subsidiaries, accepts no liability for any damage caused by any such code transmitted by or accompanying this e-mail or any attachment. The information contained in this email may be subject to the export control laws and regulations of the United States, potentially including but not limited to the Export Administration Regulations (EAR) and sanctions regulations issued by the U.S. Department of Treasury, Office of Foreign Asset Controls (OFAC). As a recipient of this information you are obligated to comply with all applicable U.S. export laws and regulations.
