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re: Re: st: Running Product Function
From
Christopher Baum <[email protected]>
To
"[email protected]" <[email protected]>
Subject
re: Re: st: Running Product Function
Date
Sun, 9 Dec 2012 22:21:44 +0000
<>
Yuval said
by appt: replace reduct_per=1 if reduct_per==0
by appt: gen y1=exp(sum(ln(reduct_per)))
Note that the first command need not be run under by-control.
On my machine, on a panel of ~18k obs, this runs about twice as fast:
by appt: gen y1=exp(sum(ln(cond(reduct_per==0, 1, reduct_per))))
Also note that in working with log() and exp() it would be a good idea to use doubles in the computation.
KIt
Kit Baum | Boston College Economics & DIW Berlin | http://ideas.repec.org/e/pba1.html
An Introduction to Stata Programming | http://www.stata-press.com/books/isp.html
An Introduction to Modern Econometrics Using Stata | http://www.stata-press.com/books/imeus.html
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