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From | Sergiy Radyakin <serjradyakin@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | st: Questions on the performance of the -expand- command |
Date | Tue, 26 Oct 2010 12:59:12 -0400 |
Hi, All! Since expand is a built-in command, this might probably be relevant only to the developers of Stata. 1) Can somebody advise if there is anything fundamental that prevents -expand- to fail immediately when there is not enough memory? Below is an example where it takes 55 seconds to realize that there is not enough memory, however it seems that the exact memory requirement can be computed beforehand and checked. An opposite case might be -reshape- where it is not immediately clear how much memory will be required. 2) The multiprocessor performance report does not list the performance of the -expand- command (or I couldn't find it??). It seems to be perfectly parallelizable both from the theoretical point of view and from actual observations, but can somebody please confirm this? Are there other commands that are missing from the MP-report? Thank you, Sergiy Radyakin . set mem 6g Current memory allocation current memory usage settable value description (1M = 1024k) -------------------------------------------------------------------- set maxvar 5000 max. variables allowed 1.947M set memory 6144M max. data space 6,144.000M set matsize 400 max. RHS vars in models 1.254M ----------- 6,147.201M r; t=0.08 12:37:56 . sysuse auto (1978 Automobile Data) r; t=0.00 12:38:00 . expand 10000000 no room to add more observations An attempt was made to increase the number of observations beyond what is currently possible. You have the following alternatives: 1. Store your variables more efficiently; see help compress. (Think of Stata's data area as the area of a rectangle; Stata can trade off width and length.) 2. Drop some variables or observations; see help drop. 3. Increase the amount of memory allocated to the data area using the set memory command; see help memory. r(901); t=55.07 12:39:08 * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/