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Re: st: glm executes very very slow


From   "G. Dai" <dgecon@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: glm executes very very slow
Date   Wed, 7 Jul 2010 13:56:20 -0700

Good advice. What confused me is that the probit runs the data very
well, while glm not.
one lesson, not trust any command not written by oneself.

On Wed, Jul 7, 2010 at 12:36 PM, Steve Samuels <sjsamuels@gmail.com> wrote:
> What you didn't  tell us, as requested by the FAQ, is what the Stata
> results were ; the coefficient for that small category would have
> stood out.
>
> The main lesson I hope you take away is not about Stata:  examine your
> data before  throwing it into a model.  That small category would have
> caused problems in any regression.
>
> By the way, the correct spelling of the program we all use is
> "Stata"--this is also in the FAQ.
>
> Steve
>
> On Wed, Jul 7, 2010 at 2:47 PM, G. Dai <dgecon@gmail.com> wrote:
>> I totally agree with the presumption statement. We are all learning by doing.
>> As a way to find out the reason for the slow, I do the followings.
>>  r`i'cenreg only takes integer value 1 to 5. obs is about 4000.
>>
>> First  I use the
>>  xi i.r`i'cenreg
>> and then run the command glm by replacing i.r`i'cenreg with _Ir`i'cenreg.
>> It is still very slow.
>>
>> And I find only 2  obs with value 1 for the variable _Ir`i'cenreg_5
>>
>> Second, I drop _Ir`i'cenreg_5 and repeat the above estimation. glm
>> works through.
>> not slow any more.
>>
>> In sum, I guess it is because I only have two obs with r`i'cenreg=5,
>> which makes the glm very
>> hard to fit the data and thus very very slow.
>>
>>
>>
>> On Wed, Jul 7, 2010 at 11:21 AM, Nick Cox <n.j.cox@durham.ac.uk> wrote:
>>> As I understand it there are two hypotheses on the table for "very very slow":
>>>
>>> 1. A bug in -glm-.
>>> 2. The complexity of your model.
>>>
>>> I put all my notional money on #2.
>>>
>>> But regardless of that, how many parameters are you estimating here?
>>>
>>> There's a kind of common presumption here that more experienced Stata users acquire some sort of Stata genius that allows them to diagnose remote problems with astounding acuteness. Not really; they're just more experienced and remember some of the mistakes they have made themselves.
>>>
>>> All this relatively experienced Stata user sees here is
>>>
>>> 1. a complicated command
>>> 2. references to a dataset I can not experiment with
>>> 3. -svy-, which is usually a sign of difficulties.
>>>
>>> So remote diagnosis is difficult.
>>>
>>> What you could do is experiment with a much simpler version of your model just to see if it too runs very slowly.
>>>
>>> Nick
>>> n.j.cox@durham.ac.uk
>>>
>>> G. Dai
>>>
>>> maybe. The r`i'cenreg only take values with 1, 2, 3,4 , and 5.
>>>
>>> On Wed, Jul 7, 2010 at 11:03 AM, Nick Cox <n.j.cox@durham.ac.uk> wrote:
>>>
>>>> I very much doubt the idea of a bug in -glm-. The point is that your syntax change is not at all trivial: it could mean many fewer parameters to estimate. Otherwise put, the issue is almost certainly the difficulty of fitting your model, rather than the size of the dataset or any problem in Stata.
>>>
>>> G. Dai
>>>
>>>> For reference only, if i replace  i.r`i'cenreg with r`i'cenreg, the
>>>> glm command runs through. but I don't know why. Maybe a bug with glm?
>>>>
>>>> On Wed, Jul 7, 2010 at 10:17 AM, G. Dai <dgecon@gmail.com> wrote:
>>>>> FYI, the dataset is about 50m with obs about 4000.
>>>>>
>>>>> On Wed, Jul 7, 2010 at 9:03 AM, G. Dai <dgecon@gmail.com> wrote:
>>>>>> hi all,
>>>>>> I guess it might be useful to open a new thread for my problem.
>>>>>>
>>>>>> I'm using glm command to estimate a fraction probit model.
>>>>>> however, when the do file goes to the following glm estimation,
>>>>>> it becomes very very slow. actually, it took me hours to finish the estimation.
>>>>>>
>>>>>> I tried it on STATA SE 11.1 in a MAC and on STATA MP 11.0 in the department
>>>>>> server.
>>>>>>
>>>>>> any help is appreciated.
>>>>>>
>>>>>> Guang
>>>>>>
>>>>>> ************************excerpt begins******************
>>>>>> svy: glm   r`i'pin r`i'`x'nhu /*parental NH stay experience*/
>>>>>>               h`i'itot h`i'atotf /*income and financial wealth*/
>>>>>>               r`i'conde r`i'adlsa r`i'iadlsa /*health condition and status*/
>>>>>>               r`i'nrshom /*past NH experience*/
>>>>>>               raedyrs  r`i'agey_b  ragender /*identity*/
>>>>>>               h`i'child r`i'hiltc /*health insurance and children*/
>>>>>>               i.r`i'cenreg,fam(bi 1) link(probit);
>>>>>> ***********************excerpt ends*****************
>>>>>> Note, where r`i'pin is the fractional variable ranges from 0 to
>>>>>> 1,which massive point at 0.
>>>
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>>
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>
>
>
> --
> Steven Samuels
> sjsamuels@gmail.com
> 18 Cantine's Island
> Saugerties NY 12477
> USA
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>
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