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From | "STANEVA A. (497186)" <A.V.STANEVA.497186@swansea.ac.uk> |
To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
Subject | st: RE: Looping with -qreg- |
Date | Thu, 19 Jan 2012 12:03:40 +0000 |
Thanks Nick for your comments. I did try with constraint option but didn't get what I need. Basically my problem is to estimate the last qreg with the new constant term (u99) 'plug' in the model. There is not noncons option in qreg. Best wishes Anita ________________________________________ From: owner-statalist@hsphsun2.harvard.edu [owner-statalist@hsphsun2.harvard.edu] on behalf of Nick Cox [njcoxstata@gmail.com] Sent: 19 January 2012 11:52 To: statalist@hsphsun2.harvard.edu Subject: Re: Looping with -qreg- [was: Re: st: Thread-Index: AczWnG9bfd8mYxtIRa2sdn3BOpo1xA==] Also, it sounds as if you want to constrain your -qreg-, which makes me feel queasy even contemplating the idea from a distance, but if so that implies trying -constraint-. Nick On Thu, Jan 19, 2012 at 11:45 AM, Nick Cox <njcoxstata@gmail.com> wrote: > Please use informative titles (subjects) for your postings. Many > people delete posts unread if they have weird titles. > > There are problems at various levels with your code. > > 1. The line > > local `b' = scalar(u99) > > looks like a mistake. If local b _was_ previously defined, then you > need to refer to what this line defines as ``b''. > > 2. But you don't refer either to `b' or to ``b'' after defining it, so > all you have done is defined something but never used it. > > 3. If local b was not previously defined, this line would not work. > But that is not what you are reporting, so my guess is that a "local > b" is defined earlier in your code. > > 4. If you have a scalar, there is no obvious need to put it into a > local for what you want to do. > > 5. I don't understand what you want to do, but you are changing > results, not instructions. Later runs of -qreg- pay no attention to > e(b) produced by earlier runs of -qreg-. > > 6. -matrix b- and -local b- are completely different entities. > > Nick > > On Thu, Jan 19, 2012 at 11:21 AM, STANEVA A. (497186) > <A.V.STANEVA.497186@swansea.ac.uk> wrote: > >> Can someone help me with this loop in a qreg? >> This first line works ok! >> >> forval i = 1/99 { >> local q = `i'/100 >> quietly qreg $y $x if public==0, quantile(`q') nolog >> matrix b = e(b) >> matrix b[1, colnumb(b,"_cons")] = scalar(u99) /*I get the constant and replace it with the scalar u99, that I want/ >> } >> >> The problem comes here. I want the replaced u99 to be included in my qreg and then to get the predictions based on that regression: >> >> forval i = 1/99 { >> local q = `i'/100 >> local `b’= scalar (u99) >> quietly qreg $y $x if public==0, quantile (`q') nolog >> predict xb if public==0 >> preserve >> keep if xb~=. >> restore >> } >> However, there is a problem in the line local`b'=scalar(u99), it seems stata doesn’t replace the _cons with the u99. It runs normal qreg, ignoring all this manipulations. >> * * 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/ * * 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/