Regarding the third question: rather than subset the data after it is in
memory try loading only the relevant subset,
-use first.dta if month<mdy(1,1,2000)-
For example:
. set memory 1m
Current memory allocation
current memory usage
settable value description (1M = 1024k)
--------------------------------------------------------------------
set maxvar 5000 max. variables allowed 1.733M
set memory 1M max. data space 1.000M
set matsize 400 max. RHS vars in models 1.254M
-----------
3.987M
. sysuse auto
(1978 Automobile Data)
. expand 275
(20276 observations created)
. keep if fore ==1
no room to add more variables due to width
An attempt was made to add a variable that would have increased the
memory required to store an observation beyond what is currently possible.
You have the following alternatives:
1. Store existing variables more efficiently; see help compress.
2. Drop some variables or observations; see help drop. (Think of
Stata's data area as the area of a rectangle; Stata can trade off width and
length.)
3. Increase the amount of memory allocated to the data area using the
set memory command; see help memory.
r(902);
. save "C:\Documents and Settings\Scott_2\Desktop\temp.dta", replace
file C:\Documents and Settings\Scott_2\Desktop\temp.dta saved
. clear
. use "C:\Documents and Settings\Scott_2\Desktop\temp.dta" if fore == 1
(1978 Automobile Data)
Scott
> -----Original Message-----
> From: [email protected] [mailto:owner-
> [email protected]] On Behalf Of Jeph Herrin
> Sent: Sunday, August 20, 2006 10:50 AM
> To: [email protected]
> Subject: Re: st: file size problems
>
> Sorry, perhaps I should have been more clear. I have 3 distinct questions:
>
> 1) Why does a 500mb file require 800mb of Stata memory?
> 2) How to get around "op. sys. refuses to supply memory" error
> when using -set mem 1000m- in winxp (when xp should be able
> to access at least 2.5gb, and no other apps are running)?
> 3) How to drop observations once the file is in memory, when
> -keep if mycondition- gives a "no room to add more obs" error
> (and there is no way to increase memory)?
>
> thanks,
> Jeph
>
>
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