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Posted to dev@systemml.apache.org by Luciano Resende <lu...@gmail.com> on 2016/05/07 03:24:03 UTC

ALS Algorithm

I was playing with the ALS algorithm (scripts/algorithms/ALS-CG.dml) and
was trying to update it to track overall losses, but I was always getting
IndexOutOfBounds. After some investigation I noticed that we define
max_iter but the code is actually as.integer(it/2) < max_iter which always
make it runs max_iter * 2.

Is there any reason for this behavior ? Otherwise let me know and I can
create a jira/fix.

Thanks

-- 
Luciano Resende
http://twitter.com/lresende1975
http://lresende.blogspot.com/

Re: ALS Algorithm

Posted by Matthias Boehm <mb...@us.ibm.com>.

ALS iteratively computes updates of left/right factors in an alternating
fashion. The script runs "max_iter*2" iterations because we conservatively
count a full update of both factors as an iteration. However, a jira/fix
for improving the script documentation is certainly useful.

Regards,
Matthias




From:	Luciano Resende <lu...@gmail.com>
To:	dev@systemml.incubator.apache.org
Date:	05/06/2016 08:41 PM
Subject:	ALS Algorithm



I was playing with the ALS algorithm (scripts/algorithms/ALS-CG.dml) and
was trying to update it to track overall losses, but I was always getting
IndexOutOfBounds. After some investigation I noticed that we define
max_iter but the code is actually as.integer(it/2) < max_iter which always
make it runs max_iter * 2.

Is there any reason for this behavior ? Otherwise let me know and I can
create a jira/fix.

Thanks

--
Luciano Resende
http://twitter.com/lresende1975
http://lresende.blogspot.com/