We have run into this.
The stata 8 version accumulates the results for you. The expression list
is/are the name of the return/global/etc. macro(s) in which your program
returns a result (or results) after each iteration. This does not stop
you from posting the results within your program if you for some reason
want to have the results in a file to further analyze the distribution
of your estimator or whatever.
You could simply declare your program as sclass, Insert an "sreturn
local whatever" at the end of your program, and the "expression" that
you would add to the bootstrap command would be `s(whatever)'. You could
do this either instead of or as well as accumulating your own results
file.
In answer to your last question, the `command' part of the bootstrap
syntax can be a program, as long as you make sure and load the program
first.
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Mike Lacy
Sent: Wednesday, September 17, 2003 9:59 AM
To: [email protected]
Subject: st: v. 8 bootstrap vs. v.7 bstrap
I have a bootstrapping program that I developed under v. 7, which I now
want to rewrite to run as native code under v.8. I am discovering that,
apparently, v.7's bstrap and v.8's bootstrap are more different than the
help documentation indicates. My immediate difficulty is this: My
bstrap
usage in the v.7 code took a program of my own ("MyProg")as an argument,
and several user-defined quantities were calculated and posted within
the
program. The bstrap command looked like this:
bstrap MyProg, size(100) reps(1000)
Under v.8, this usage occasions an error message indicating that this
command lack an an "expression list," but that seems irrelevant to me,
since MyProg does its own posting. Can someone enlighten me here about
how
to satisfy bootstrap's apparent desire for an expression list? Perhaps
this
is documented in the hard copy manuals (which I didn't buy) but not in
the
program help?
Also, I notice that the grammar for bootstrap in v. 8 indicates that it
is
intended to take a command rather than a program as an argument,
although
there is a reference in the help text indicating that it can take a user
program, as did bstrap. Is there some significant change in the
bootstrapping facilities between v.7 and v.8?
Regards,
=-=-=-=-=-=-=-=-=-=-=-=-=
Mike Lacy
Fort Collins CO
(970) 491-6721 office
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