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https://issues.apache.org/jira/browse/SPARK-11302?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14974589#comment-14974589
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eyal sharon commented on SPARK-11302:
-------------------------------------
Cool , I will try although I hope I fully captured all questions
1- Logpdf is also returns non reasonable value . mg.logpdf(Vectors.dense(
629,640,1.7188,618.19)) = -3891330.078277891 ( the exp is zero )
2 - my MU vector values -
[1055.3910505836575,1070.489299610895,1.39020554474708,1040.5907503867697]
3 - the correct answer , as return from Matlab for this given data point
mg.pdf(Vectors.dense(629,640,1.7188,618.19)) is around e-05
4- when running the model with a non covariance matrix , model yields
pdf - 7.293362507983666E-11, logpdf -23.341471333876257 . Again , these
results match with the Matlab model
5- these are the printed values from my script
mu:
[1055.3910505836575,1070.489299610895,1.39020554474708,1040.5907503867697]
sigma:
166769.00466698944 0.0 0.0 0.0
0.0 172041.5670061245 0.0 0.0
0.0 0.0 0.872524191943962 0.0
0.0 0.0 0.0 161848.9196719207
sigmaCov:
166769.00466698944 169336.6705268059 12.820670788921873
164243.93314092053
169336.6705268059 172041.5670061245 21.62590020524533
166678.01075856484
12.820670788921873 21.62590020524533 0.872524191943962
4.283255814732373
164243.93314092053 166678.01075856484 4.283255814732373
161848.9196719207
I hope it helps.
Best, Eyal
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> Multivariate Gaussian Model with Covariance matrix return zero always
> ------------------------------------------------------------------------
>
> Key: SPARK-11302
> URL: https://issues.apache.org/jira/browse/SPARK-11302
> Project: Spark
> Issue Type: Bug
> Components: MLlib
> Reporter: eyal sharon
> Priority: Minor
>
> I have been trying to apply an Anomaly Detection model using Spark MLib.
> As an input, I feed the model with a mean vector and a Covariance matrix.
> ,assuming my features contain Co-variance.
> Here are my input for the model ,and the model returns zero for each data
> point for this input.
> MU vector -
> 1054.8, 1069.8, 1.3 ,1040.1
> Cov' matrix -
> 165496.0 , 167996.0, 11.0 , 163037.0
> 167996.0, 170631.0, 19.0, 165405.0
> 11.0, 19.0 , 0.0, 2.0
> 163037.0, 165405.0 2.0 , 160707.0
> Conversely, for the non covariance case, represented by this matrix ,the
> model is working and returns results as expected
> 165496.0, 0.0 , 0.0, 0.0
> 0.0, 170631.0, 0.0, 0.0
> 0.0 , 0.0 , 0.8, 0.0
> 0.0 , 0.0, 0.0, 160594.2
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