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From |
Anne Resende <A.C.C.Resende@rhul.ac.uk> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: AW: st: Programming stata using egen functions |

Date |
Tue, 28 Apr 2009 20:48:09 +0100 (BST) |

I swear that this is my last email: I trying to calculate bounds on E[y(t)]. So I need to calculate the lower bound and also a confidence interval on it using boostrap. So I am trying to calculate: (1) (2) SUM max( E[y|z=s] + max {(E[y|z=s']-E[u|z=u]/(s'-u))*(t-s')}) (s>=t) (s'|s>=s'>=t} {u|u<t} (Okumura and Usui, 2006 pag.4). So here we have s,s’,t and u: every letter goes from 8 to 20. I decide to do a program for each, t=8,...,20. (So I am trying to calculate the lower bound for each t). I also have tried to use all of t together (also create forvalues for t) but stata gives a message “No room to add more variables”. In the program that I already sent to you I am considering that t is equal 9, so u=8 because u<9 (I do this in line 7 : qui sum `1' if u==8 ). So I have tried to use rowmax() to calculate the maximum of the first max parenthesis (lines 9 and 11- part (1) + (2)), doesn’t matter if I calculate (2) and take the max or sum (1) and (2) and take the max, as I have to take the max again). Then in the reminding lines I have tried to multiply (3) {(1)+(2)}, the whole equation by P(z=s) and then use rowtotal to sum all of these observations, as I have to sum over s>=t. (lines 15 and 16 of the programe) I am afraid that this could be less clear than before but is exactly what I trying to do. Of course that I do not expect you create an ado file for me. I just want some tips or some help as you all know much more about stata programming. So I really need to move the calculation of the maximum outside the loop? Many thanks Nick Cox wrote: >Quite so, and not a problem. It's my point 1 that is more important. > >Nick >n.j.cox@durham.ac.uk > > >-----Original Message----- >From: Anne Resende [mailto:A.C.C.Resende@rhul.ac.uk] >Sent: 28 April 2009 19:02 >To: Nick Cox >Subject: RE: st: Programming stata using egen functions > > >2. "You don't know enough Stata to do what you want without help." >That is why I decided to send an email to statalist. >Thanks anyway >Anne > > > Martin Weiss wrote: > ><> > >True, I was too focused on the issue with the -scalar- and -local- problem to notice that -rowtotal()- was not the best example. > >Overall, I am sensing an overwhelming willingness to help Anne, but she should try to describe _verbally_ what she wants to achieve, and I am sure no more than a couple of lines will be necessary to get there. Maarten has already had a stab at it... > > >HTH >Martin > > >-----Ursprüngliche Nachricht----- >Von: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Nick Cox >Gesendet: Dienstag, 28. April 2009 19:43 >An: statalist@hsphsun2.harvard.edu >Betreff: RE: st: Programming stata using egen functions > >But then the -rowtotal()- is pointless. As Kit pointed out several posts ago, the row total of one item is precisely that item. > >Nick >n.j.cox@durham.ac.uk > >Martin Weiss > >Better example > >************* >tempvar ep_`s' >gen `ep_`s''=exem2_`s'*`P1_`s'' >qui egen `ep2_`s''=rowtotal(`ep_`s'') >************* > >Martin Weiss > >" So in line 9 I substitute `scalar’ for `local’ hoping >that rowmax() could now recognize the varlist." > >Well, you have not passed a -varlist- to -egen, rowmax()- so it complains about its syntax statement not being respected, and rightly so. -local-s and -scalar-s are equally bad, in this respect. If that is all that is standing between you and success, then let the -gen- and -egen- statements refer to -tempvar-s. In this fashion, at least they will be legal... > > >So instead of > >** >qui summarize `1' if `sp'==u >local mean1_`s'`sp' =r(mean) >** > >say -egen mean1_ssp=mean(`1') if `sp'==u- > >Anne Resende > >Thanks a lot for all answers!! >Just to clarify some points: >I understood that the egen functions rowmax() and rowtotal() did not >accept scalar. So in line 9 I substitute `scalar’ for `local’ hoping >that rowmax() could now recognize the varlist. But stata returns de >same error message. I need the rowmax() function to returns the maximum >values between the varilist. (the maximum values within each `s’) > >So I have tried: >program mymean, rclass > 1. syntax [varlist] [if] > 2. tokenize "`varlist'" > 3. forvalues s=9(1)20 { > 4. forvalues sp=9(1)`s' { > 5. qui summarize `1' if `sp'==u > 6. local mean1_`s'`sp' =r(mean) > 7. qui sum `1' if u==8 > 8. local mean2_`s'`sp' =r(mean) > 9. local m_`s'`sp'=`mean1_`s'`sp'' + ((`mean1_`s'`sp'' - >`mean2_`s'`sp'')/(`sp'-8))*(9-`sp') > 10. tempvar exem_`s' P_`s' ep_`s' ep2_`s' > 11. qui egen `exem_`s''=rowmax(m_`s'`sp') > 12. qui gen `P_`s''=sum(P) if `s'==u & id==1 > 13. qui sum `P_`s'', meanonly > 14. local P1_`s'=r(max) > 15. scalar ep_`s'=exem2_`s'*`P1_`s'' > 16. qui egen `ep2_`s''=rowtotal(ep_`s') > 17. return scalar eq2=`ep2_`s'' > 18. } > 19. } > 20. end > >end of do-file >. mymean loghw >variable m_99 not found >r(111); > >1) I understand the differences between egen sum( )and stata fuctions >sum(), but neither gives me what I need. I intend to use rowtotal() >because it sums the observations on the rows not on the columns as egen >sum() and sum() do. > >2) Sorry about: return scalar eq29=rowtotal(ep_`s') that I wrote in >the other email.. I know that it’s wrong > >3)What is my aim? As I told I need to end up with one variable in order >to run the bootstrap. >I want to the create the program mymean and then run: bootstrap r(eq2), >reps(#) seed(#) : mymean loghw (I am following the idea on: >http://www.stata.com/capabilities/boot.html) > >4)I think that I cannot use a do.file because I will end up with a >constant (I also tried) and so I could not run the bootstrap. Creating >and ado file the program allows me to use the boots after. > >So all I want to do is to write a program to calculate my statistics of >interest and then apply the bootstrap. And my problem is how I can >construct a varlist in order to run my program using rowmax() and >rowtotal(). Or maybe there is another way to do that without having to >use rowmax() and rowtotal() functions. >I hope that is clearer now, >Thanks >Anne > >Thanks >Anne > > >Richard Ochmann wrote: > > >>... >>not entirely clear what you want to do there, >>but maybe you can borrow from this code on generating a list of scalars >>(which might be inefficient either): >> >>*** >>#delimit; >>sysuse auto; >>local meanlist = "0"; >>forvalues i = 1/2 {; >>forvalues j = `i'/3 {; >>quietly sum price, meanonly; >>scalar s`i'`j' = r(mean)/runiform(); >>local meanlist = " `meanlist', `=s`i'`j'' "; >>di "`meanlist'"; >>scalar mymax = max(`meanlist'); >>di mymax; >> }; >> }; >>*** >> >>best, rich >> >> >>owner-statalist@hsphsun2.harvard.edu schrieb am 28.04.2009 02:05:25: >> >>> Dear All >>> I am having some problems with my ado.file whenever I try to include >>> some egen functions like rowmax and rowtotal. I am currently using >>> Stata 10.0 >>> >>> My ado program is: >>> >>> program mymean, rclass >>> 1. syntax [varlist] [if] >>> 2. tokenize "`varlist'" >>> 3. forvalues s=9(1)20 { >>> 4. forvalues sp=9(1)`s' { >>> 5. qui summarize `1' if `sp'==u >>> 6. local mean1_`s'`sp' =r(mean) >>> 7. qui sum `1' if u==8 >>> 8. local mean2_`s'`sp' =r(mean) >>> 9. scalar m_`s'`sp'=`mean1_`s'`sp'' + ((`mean1_`s'`sp'' - >>> `mean2_`s'`sp'')/(`sp'-8))*(9-`sp') >>> 10. tempvar exem_`s' P1_`s' P_`s' ep_`s' ep2_`s' >>> 11. qui egen `exem_`s''=max(m_`s'`sp') >>> 12. return scalar exem2_`s'=`exem_`s''*1 >>> 13. qui gen `P1_`s''=sum(P) if `s'==u & id==1 >>> 14. qui egen `P_`s'' =max(`P1_`s'') >>> 15. scalar ep_`s'=exem2_`s'*`P_`s'' >>> 16. qui gen `ep_`s''=exem2_`s'*`P_`s'' >>> 17. return scalar eq29=sum(ep_`s') >>> 18. } >>> 19. } >>> 20. end >>> This program is running well. But in lines 11 and 17, I in fact need >to >>> use the commands rowmax rather than max and rowtotal rather sum. So >>> when I use max and sum the program runs well but when I substitute >this >>> commands whith rowmax and rowtotal stata gives me the following error >>> message after I typed mymean loghw: >>> >>> >>> program mymean, rclass >>> 1. syntax [varlist] [if] >>> 2. tokenize "`varlist'" >>> 3. forvalues s=9(1)20 { >>> 4. forvalues sp=9(1)`s' { >>> 5. qui summarize `1' if `sp'==u >>> 6. local mean1_`s'`sp' =r(mean) >>> 7. qui sum `1' if u==8 >>> 8. local mean2_`s'`sp' =r(mean) >>> 9. scalar m_`s'`sp'=`mean1_`s'`sp'' + ((`mean1_`s'`sp'' - >>> `mean2_`s'`sp'')/(`sp'-8))*(9-`sp') >>> 10. tempvar exem_`s' P1_`s' P_`s' ep_`s' ep2_`s' >>> 11. qui egen `exem_`s''=rowmax(m_`s'`sp') >>> 12. return scalar exem2_`s'=`exem_`s''*1 >>> 13. qui gen `P1_`s''=sum(P) if `s'==u & id==1 >>> 14. qui egen `P_`s'' =max(`P1_`s'') >>> 15. scalar ep_`s'=exem2_`s'*`P_`s'' >>> 16. qui gen `ep_`s''=exem2_`s'*`P_`s'' >>> 17. return scalar eq29=rowtotal(ep_`s') >>> 18. } >>> 19. } >>> 20. end >>> . >>> end of do-file >>> . mymean loghw >>> variable m_99 not found >>> r(111); >>> >>> So I would like to know why the program recognizes the max and sum >egen >>> functions but do not recognize (or do not find my variable) when I use >>> the rowmax and rowtotal egen functions. Is there any programming >>> differences between these two kind of egen functons? > >* >* 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/ > * * 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/

**Follow-Ups**:**RE: AW: st: Programming stata using egen functions***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**Re: AW: st: Programming stata using egen functions***From:*Maarten buis <maartenbuis@yahoo.co.uk>

**st: Adjusted standard errors***From:*"Kaganova, Yevgeniya" <ykaganova@rti.org>

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