Re: st: ereturn post, obs(#) - does the # in obs() option have a size limit?

[Joseph Luchman <jluchman@gmail.com>]

Thanks, Sergiy.

I may contact Stata tech support to get their take on this issue as
well (and to determine if it is, in fact, a bug).

- joe

Joseph Nicholas Luchman, Ph.D.
----
Behavioral Statistics Lead | Fors Marsh Group
Email: jluchman@forsmarshgroup.com
forsmarshgroup.com
https://www.researchgate.net/profile/Joseph_Luchman/

>Dear Joseph,
>
>I confirm the problem also in Stata 13.0.
>
>Furthermore, if you set obs to 1000001 it is working again. It seems
>that somewhere inside obs() it is checking for the number to be of
>type long, and does not recognize all the numbers above a certain
>threshold. (E.g. if the value of 10^6 is internally something like
>1000000.0000000023 see posts on precision).
>
>Value e.g. 1999990000 is possible to pass back, but 2999990000 no. The
>exact max should be 2,147,483,647
>See: help limits
>
>But apparently as you discovered not all values from this range are accepted.
>
>I tried to apply floor() to the argument, but to no effect.
>Seems like a bug, but it doesn't seem to affect the internal
>(built-in) Stata's estimation commands (tried regress on a 1mln
>dataset), presumably the check is engaged only when the nobs() is set
>by the user, and Stata trusts its own commands will never supply a
>wrong (non-integer) value for nobs.
>
>Best, Sergiy Radyakin
>
>On Thu, Feb 20, 2014 at 4:34 PM, Joseph Luchman <jluchman@gmail.com> wrote:
> Hi Statalist,
>
>   I've been working with this problem for some time now, I'm at an
> impasse and am beginning to wonder if it is a problem with the obs(#)
> option of ereturn post itself - but I thought I'd try posting to the
> list to make sure it's not something I'm overlooking that is producing
> this behavior.
>
>   To summarize, it seems that the obs(#) option of ereturn post
> returns missing values for numbers of observations that are too high
> (e.g., one million).  The same problem doesn't seem to affect
> separating out the scalar though.
>
>   I should note that I'm running Stata version 12.1.
>
>   Representative issue is covered below in the example syntax below:
>
> version 12.1
>
> program define count_then_post1, eclass
> count
> ereturn post , obs(`=r(N)')
> end
>
> program define count_then_post2, eclass
> count
> ereturn scalar N = `=r(N)'
> end
>
> set obs 100
>
> count_then_post1
>
> ereturn list //result here is e(N) = 100
>
> count_then_post2
>
> ereturn list //result here is e(N) = 100
>
> clear
>
> set obs 1000000
>
> count_then_post1
>
> ereturn list //result here is missing
>
> count_then_post2
>
> ereturn list //result here is e(N) = 1000000
>
> - joe
>
> Joseph Nicholas Luchman, Ph.D.
> ----
> Behavioral Statistics Lead | Fors Marsh Group
> Email: jluchman@forsmarshgroup.com
> forsmarshgroup.com
> https://www.researchgate.net/profile/Joseph_Luchman/
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