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https://issues.apache.org/jira/browse/MAHOUT-1531?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Andrew Palumbo updated MAHOUT-1531:
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Description:
The APLHA_I CLI option accepts a float for what should (according to the paper)
be a vector of floats (or more correctly a path to a SequenceFile containing
word, alpha_i pairs for each word in the respective dictionary). The current
MapReduce NB implementation treats APLHA_I as a constant float where it should
be a vector (ALPHA) of floats (smoothing parameter per word).
However as (Rennie et al.) sec 2.2 uses a constant ALPHA_I = 1 and the NB
implementation defaults to APLHA_I = 1 and is an implementation of Rennie,
there is not really a problem.
To avoid confusion, I think its a good idea to remove the option to set ALPHA_I
and to keep ALPHA_I a constant 1.0 in NB.
was:
The APLHA_I CLI option accepts a float for what should be a vector of floats
(or more correctly a path to a SequenceFile containing word, alpha_i pairs for
each word in the respective dictionary). The current MapReduce NB
implementation treats APLHA_I as a constant float where it should be a vector
(ALPHA) of floats (smoothing parameter per word).
However as (Rennie et al.) sec 2.2 uses a constant ALPHA_I = 1 and the NB
implementation defaults to APLHA_I = 1 and is an implementation of Rennie,
there is not really a problem.
To avoid confusion, I think its a good idea to remove the option to set ALPHA_I
and to keep ALPHA_I a constant 1.0 in NB.
> Remove ALPHA_I CLI option in NB
> -------------------------------
>
> Key: MAHOUT-1531
> URL: https://issues.apache.org/jira/browse/MAHOUT-1531
> Project: Mahout
> Issue Type: Bug
> Components: Classification, CLI
> Affects Versions: 0.9
> Environment:
> Reporter: Andrew Palumbo
> Priority: Minor
> Fix For: 1.0
>
>
> The APLHA_I CLI option accepts a float for what should (according to the
> paper) be a vector of floats (or more correctly a path to a SequenceFile
> containing word, alpha_i pairs for each word in the respective dictionary).
> The current MapReduce NB implementation treats APLHA_I as a constant float
> where it should be a vector (ALPHA) of floats (smoothing parameter per word).
>
> However as (Rennie et al.) sec 2.2 uses a constant ALPHA_I = 1 and the NB
> implementation defaults to APLHA_I = 1 and is an implementation of Rennie,
> there is not really a problem.
> To avoid confusion, I think its a good idea to remove the option to set
> ALPHA_I and to keep ALPHA_I a constant 1.0 in NB.
>
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