Statalist


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: st: RE: exact command for distance ?


From   Roy Wada <roywada@hotmail.com>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: RE: exact command for distance ?
Date   Fri, 11 Sep 2009 14:47:17 -0700

Austin,
 
Thanks for your feedback. You seem to be contradicting yourself 
on occassions but some people do that now and then.
 
If vincenty is critical, then why are you now recommending codes
not based on vincenty? You already know that vincenty makes no 
important differences for the distance less than 100 miles.
 
Please do make the calculations for us and tell us how this 
will impact someone's research.
 
I agree -distmatch- can be made to run faster (it should recycle 
previous rankings) but not for the reason you posted.

Your are forgeting to mention that your codes cannot perform ranking 
or complete matching. It only looks for the minimum distance.
 
This has been pointed out you before.
 
I would post another comparison except for the fact that your codes
do not work for other matchings.
 
You seem to be creating a moving target with ad hoc fixes, and
suggest other people do the same. If they can do this, why would 
they need you?
 
Are we stuck in the twilight zone where people does not need help 
but in fact should be made to take one when offered.
 
There is something funny about people who claim exlusive expertise.
 
Let's agree it is a very bad idea to tell other people to not use 
someone's else program.
 
Roy

P.S. You can take your download programs to the data center just 
like other programss. Just put it in the current directory if you 
still do not know how to do this.
 
 
> Roy--
> I also have no problem downloading others' work, and my hard drive is
> cluttered with the output of Jann, Baum, Schaffer, Jenkins, Cox, and
> many others. I seem to use one of Ben Jann's programs every day. And
> one of my posted solutions on this topic requires downloading
> -vincenty- (from SSC), which gives much better distance estimates,
> though at a substantial time cost.
>
> I am not even claiming that -distmatch- has no utility--no doubt many
> will find it useful. But I'm afraid I don't see your point in this
> post at all--you claim in the help file that -distmatch- "take several
> minutes to complete" for 3000 obs, and other methods take "days if not
> weeks" yet the method that I have outlined in several posts is
> entirely general (i.e. it can be customized to produce any range of
> statistics for any range of neighbors, which no program can claim to
> do) and runs faster than -distmatch- in many cases, e.g. by a factor
> of four or five here:
>
_________________________________________________________________
Windows Live: Make it easier for your friends to see what you’re up to on Facebook.
http://windowslive.com/Campaign/SocialNetworking?ocid=PID23285::T:WLMTAGL:ON:WL:en-US:SI_SB_facebook:082009
*
*   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/



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