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seen Aug 12 '12 at 11:06
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Aug
8
comment Initial values for logistic regression using maximum likelihood
In addition, I've tried running glm, then taking the output coefficients and put them as start values to the mle. In this case I get almost the same results (and got acceleration in performance)
Aug
8
comment Initial values for logistic regression using maximum likelihood
for example, here are the first 7 coefficients in the glm run: -6.2307913208130525, 6.110187257533295e-06, -2.0577042478307273, 0.4786093240660332, 0.38126727104872804, -0.625615435816033, 0.04482479648912922 And the first 7 coefficients in the mle2 run (with zeros start values): -1.4625013759985311e-08, -0.0005046844214205488, 1.2295071793926704e-08, 1.632233091079531e-08, -1.8873962762517583e-08, -6.607669091467728e-09. You can see that it seems that it was "stuck" in a local minimum near 0,0,0,0,0,....
Aug
8
comment Initial values for logistic regression using maximum likelihood
I'm not using glm, so as I understand safeBinaryRegression can't help me. What I've done is implemented my own log likelihood function and used maximum likelihood (R's mle2 - bbmle) to find the coefficients. I've compared the results to regular glm (which works without any problems). mle2 should get start values. Currently I'm using zeros for all the coefficients. When I'm using those start values, in some cases I get very weird results (the differences between the mle2 results and the glm results are big). So I wanted to know what are the start values that glm uses
Aug
7
comment Initial values for logistic regression using maximum likelihood
I have around 20,000 vectors with ~20 features per vector. The features has some dependencies between them. y values are 0 or 1 with around 1-5% or ones (hope that help, because I can't add all the data here...
Aug
7
asked Initial values for logistic regression using maximum likelihood
Jun
14
comment Using generalized method of moments (GMM) to calculate logistic regression parameter
Yes, we're looking for something that has probability between 0-0.25 and not between 0-1.
Jun
14
comment Using generalized method of moments (GMM) to calculate logistic regression parameter
We also trying to use Maximum likelihood, but would like to compare the results with GMM
Jun
14
comment Using generalized method of moments (GMM) to calculate logistic regression parameter
In the specific case where A=1 we get regular logistic regression
Jun
14
awarded  Commentator
Jun
14
comment Using generalized method of moments (GMM) to calculate logistic regression parameter
fixed on all observations (like b0, b1, ...)
Jun
14
comment Using generalized method of moments (GMM) to calculate logistic regression parameter
either way. I can put it as an input (e.g.A = 0.25) or be one of the coefficients to be found
Jun
14
asked Using generalized method of moments (GMM) to calculate logistic regression parameter
Dec
28
comment Changing logistic regression's loss function
there are several different functions. I get the "score" for the probabilities estimation according to these functions, so I want, the fitted function to be estimated according to those "scores" (and not just by using maximum likelihood
Dec
28
comment Changing logistic regression's loss function
But is there any other method to fit a logit function to a 0s & 1s response using a different loss function?
Dec
28
asked Changing logistic regression's loss function
Jul
22
awarded  Supporter
Jul
22
comment Feature selection for low probability event prediction
One more thing - I had some problems running "advanced" (RF, l1,...) classifiers on all my dataset (because of its size...), So I'm thinking of using weighting / data reduction, but again, I have a problem with finding the right probability (I found that finding the right probability after weighting is not straight forward..., though I haven't yet tried the methods that were mentioned above) Thanks!
Jul
22
comment Feature selection for low probability event prediction
I agree, however the problem with using l1/l2-regularized regression (LARS or logistic regressions), is that as far as I understand (and maybe I'm wrong), you don't get the right probability because of the regularization (is that correct?). In addition we found out that the logistic regression gives us better results in probability estimation than linear regression, when running on the entire dataset.
Jul
21
comment Feature selection for low probability event prediction
mmm... very interesting. In this case, do you think we should apply weighting (or "zero" reduction) before the classification? I will also check this. Thanks!
Jul
21
comment Feature selection for low probability event prediction
In addition, we can't weight our samples and still get the right probability. We haven't tried PCA yet, but its on our TODO :) Do you have any suggestions? Thanks a lot!