Statalist The Stata Listserver


[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

st: RE: processing time


From   "McKenna, Timothy" <Timothy.McKenna@NERA.com>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: RE: processing time
Date   Thu, 22 Mar 2007 14:04:43 -0400

I think dropping both in one step is faster:

Profiler results:

both
    99   75.021  both
Overall total count =     99
Overall total time  =     75.021 (sec)



separate
    99   96.438  separate
Overall total count =     99
Overall total time  =     96.438 (sec)



-------------- Begin do file ------------------- 

#delimit;
version 9.2;
capture program drop _all;

clear;
set mem 100m;
set seed 12345;

set obs 1000000;
local tests 100;

gen a = uniform(); qui replace a = . if a > 0.5;
gen b = uniform(); qui replace b = . if b > 0.5;

program define both;
preserve;
quietly drop if a == . | b == .;
restore;
end;

program define separate;
preserve;
quietly drop if a == .;
quietly drop if b == .;
restore;
end;

profiler on;
local i = 1;
while `i' < `tests' {;
	both;
	local i = `i' + 1;
	};
profiler off; profiler report; profiler clear;

profiler on;
local i = 1;
while `i' < `tests' {;
	separate;
	local i = `i' + 1;
	};
profiler off; profiler report; profiler clear;

-------------- End do file ------------------- 

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Jon Schwabish
Sent: Thursday, March 22, 2007 12:55 PM
To: statalist@hsphsun2.harvard.edu
Subject: st: processing time

Quick question:

Which is more efficient (in terms of processing time)?

drop if a==.
drop if b==.

  OR 

drop if a==. | b==.

(where a and b are any variables of choice).

Thanks.


 
________________________________________________________________________
____________
Don't pick lemons.
See all the new 2007 cars at Yahoo! Autos.
http://autos.yahoo.com/new_cars.html 
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/ 
  
_____________________________________________________________ 
  
This e-mail and any attachments may be confidential or legally privileged.  If you received this message in error or are not the intended recipient, you should destroy the e-mail message and any attachments or copies, and you are prohibited from retaining, distributing, disclosing or using any information contained herein.  Please inform us of the erroneous delivery by return e-mail.  
  
Thank you for your cooperation. 
  
_____________________________________________________________ 
 

*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index