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Date: Tue, 6 Sep 2011 10:53:08 -0700
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Subject: Re: how to run PCA from Mahout
From: Dmitriy Lyubimov <dlieu.7@gmail.com>
To: user@mahout.apache.org, Amr Desoky <amr_desoky@yahoo.com>
Cc: "mahout-user@lucene.apache.org" <mahout-user@lucene.apache.org>
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I am sorry, i meant 'subtract a mean', not median. That's for PCA.

On Tue, Sep 6, 2011 at 10:50 AM, Dmitriy Lyubimov <dlieu.7@gmail.com> wrote=
:
> You need to massage your data to compute (and subract) a median first,
> as far as i understand. That should be relatively easy to do. Then you
> can run a distributed SVD on it ('bin/mahout ssvd' command from trunk
> should be quite good to try).
>
> -d
>
>
> On Tue, Sep 6, 2011 at 5:33 AM, Amr Desoky <amr_desoky@yahoo.com> wrote:
>> Hi,
>> =A0 It is mentioned on the web site : https://cwiki.apache.org/confluenc=
e/display/MAHOUT/Algorithms
>> =A0 That you implement the following algorithms within Mahout :
>> =A0=A0=A0 =A0Gaussian Discriminative Analysis
>> =A0 =A0 Independent Component Analysis
>> =A0 =A0Principal Components Analysis
>>
>> But unfortunately, I could not find any help or documentation=A0 on how =
to use these algorithms!!
>> specially=A0 I would like to try PCA on a huge data set of ~10Million ve=
ctors of 400 components each.
>>
>> Please give me some help on how to run PCA (and also ICA, GDA) whatever =
available.
>>
>> Best regards,
>> Amr
>>
>>
>> Amr Ibrahim El-Desoky, Mousa
>> PhD Student, Computer Science (i6),
>> RWTH-Aachen University,
>> Aachen, Germany
>> Cel.=A0=A0=A0 =A0: +49 0176 56418470
>> Office : +49 241 8021620
>> Fax=A0=A0=A0 =A0 : +49 241 8022219
>