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From |
Maarten buis <maartenbuis@yahoo.co.uk> |

To |
statalist@hsphsun2.harvard.edu |

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

Date |
Wed, 29 Apr 2009 08:40:34 +0000 (GMT) |

Sounds to me like you can avoid loops by making clever use of -reshape- and -by-, see their helpfiles. -- Maarten ----------------------------------------- Maarten L. Buis Institut fuer Soziologie Universitaet Tuebingen Wilhelmstrasse 36 72074 Tuebingen Germany http://home.fsw.vu.nl/m.buis/ ----------------------------------------- --- On Tue, 28/4/09, Anne Resende <A.C.C.Resende@rhul.ac.uk> wrote: > From: Anne Resende <A.C.C.Resende@rhul.ac.uk> > Subject: Re: AW: st: Programming stata using egen functions > To: statalist@hsphsun2.harvard.edu > Date: Tuesday, 28 April, 2009, 8:48 PM > 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/ * * 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/

**References**:**Re: AW: st: Programming stata using egen functions***From:*Anne Resende <A.C.C.Resende@rhul.ac.uk>

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