Re: parallelALS and RMSE TEST

2014-03-01 Thread Sebastian Schelter
The output of parallelALS are two matrices U and M whose product is an approximation of your input matrix. The matrices are outputed as sequence files with an IntWritable as key (the index of the row in the matrix) and a VectorWritable as value which holds the contents of the row vector.

Re: parallelALS and RMSE TEST

2014-02-27 Thread AJ Rader
Sean Owen srowen at gmail.com writes: Parallel ALS is exactly an example of where you can use matrix factorization for 0/1 data. On Mon, May 6, 2013 at 9:22 PM, Tevfik Aytekin tevfik.aytekin at gmail.com wrote: Hi Sean, Isn't boolean preferences is supported in the context of

Re: parallelALS and RMSE TEST

2013-05-06 Thread William
Ted Dunning ted.dunning at gmail.com writes: WIthout more information it is impossible to comment. What experiments? On Fri, May 3, 2013 at 8:45 AM, William icswilliam2010 at gmail.com wrote: I'm trying to get some recommendations with three Algorithms: 1.parallelALS

Re: parallelALS and RMSE TEST

2013-05-06 Thread Sean Owen
If you have no ratings, how are you using RMSE? this typically measures error in reconstructing ratings. I think you are probably measuring something meaningless. On Mon, May 6, 2013 at 10:17 AM, William icswilliam2...@gmail.com wrote: I have a dataset about user and movie(no rate).But I want to

Re: parallelALS and RMSE TEST

2013-05-06 Thread Sean Owen
ALS-WR weights the error on each term differently, so the average error doesn't really have meaning here, even if you are comparing the difference with 1. I think you will need to fall back to mean average precision or something. On Mon, May 6, 2013 at 11:24 AM, William icswilliam2...@gmail.com

Re: parallelALS and RMSE TEST

2013-05-06 Thread Tevfik Aytekin
This problem is called one-class classification problem. In the domain of collaborative filtering it is called one-class collaborative filtering (since what you have are only positive preferences). You may search the web with these key words to find papers providing solutions. I'm not sure whether

Re: parallelALS and RMSE TEST

2013-05-06 Thread Sean Owen
Yes, it goes by the name 'boolean prefs' in the project since target variables don't have values -- they just exist or don't. So, yes it's certainly supported but the question here is how to evaluate the output. On Mon, May 6, 2013 at 8:29 PM, Tevfik Aytekin tevfik.ayte...@gmail.com wrote: This

Re: parallelALS and RMSE TEST

2013-05-06 Thread Tevfik Aytekin
Hi Sean, Isn't boolean preferences is supported in the context of memory-based recommendation algorithms in Mahout? Are there matrix factorization algorithms in Mahout which can work with this kind of data (that is, the kind of data which consists of users and the movies they have seen). On

Re: parallelALS and RMSE TEST

2013-05-06 Thread Sean Owen
Parallel ALS is exactly an example of where you can use matrix factorization for 0/1 data. On Mon, May 6, 2013 at 9:22 PM, Tevfik Aytekin tevfik.ayte...@gmail.com wrote: Hi Sean, Isn't boolean preferences is supported in the context of memory-based recommendation algorithms in Mahout? Are

Re: parallelALS and RMSE TEST

2013-05-06 Thread Tevfik Aytekin
But the data under consideration here is not 0/1 data, it contains only 1's. On Mon, May 6, 2013 at 11:29 PM, Sean Owen sro...@gmail.com wrote: Parallel ALS is exactly an example of where you can use matrix factorization for 0/1 data. On Mon, May 6, 2013 at 9:22 PM, Tevfik Aytekin

Re: parallelALS and RMSE TEST

2013-05-06 Thread Sean Owen
Yes, that's really what I mean. ALS factors, among other things, a matrix of 1 where an interaction occurs and nothing (implicitly 0) everywhere else. On Mon, May 6, 2013 at 9:40 PM, Tevfik Aytekin tevfik.ayte...@gmail.com wrote: But the data under consideration here is not 0/1 data, it contains

parallelALS and RMSE TEST

2013-05-03 Thread William
I'm trying to get some recommendations with three Algorithms: 1.parallelALS 2.evaluateFactorization 3.recommendfactorized In my experiments, RMSE value monotonically increases with larger numfeatures. But Base on Netflix Prize experiment, RMSE should decreases with larger numfeatures. How to

Re: parallelALS and RMSE TEST

2013-05-03 Thread Ted Dunning
WIthout more information it is impossible to comment. What experiments? On Fri, May 3, 2013 at 8:45 AM, William icswilliam2...@gmail.com wrote: I'm trying to get some recommendations with three Algorithms: 1.parallelALS 2.evaluateFactorization 3.recommendfactorized In my experiments,