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Sean Owen commented on MAHOUT-391: ---------------------------------- Bleh, that's not much of a difference at all. Are these dense vectors? this wouldn't help them much at all, indeed. But I'd be surprised if normal-ish sparse vectors aren't 20% smaller or more. > Make vector more space efficient with variable-length encoding, et al > --------------------------------------------------------------------- > > Key: MAHOUT-391 > URL: https://issues.apache.org/jira/browse/MAHOUT-391 > Project: Mahout > Issue Type: Improvement > Affects Versions: 0.3 > Reporter: Sean Owen > Assignee: Sean Owen > Priority: Minor > Fix For: 0.4 > > Attachments: MAHOUT-391.patch > > > There are a few things we can do to make Vector representations smaller on > disk: > - Use variable-length encoding for integer values like size and element > indices in sparse representations > - Further, delta-encode indices in sequential representations > - Let caller specify that precision isn't crucial in values, allowing it to > store values as floats > Since indices are usually small-ish, I'd guess this saves 2 bytes or so on > average, out of 12 bytes per element now. > Using floats where applicable saves another 4. Not bad. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.