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 <[email protected]> wrote:
> From: Anne Resende <[email protected]>
> Subject: Re: AW: st: Programming stata using egen functions
> To: [email protected]
> 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
> >[email protected]
> >
> >
> >-----Original Message-----
> >From: Anne Resende [mailto:[email protected]]
> >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: [email protected]
> [mailto:[email protected]] Im Auftrag
> von Nick Cox
> >Gesendet: Dienstag, 28. April 2009 19:43
> >An: [email protected]
> >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
> >[email protected]
> >
> >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
> >>
> >>
> >>[email protected] 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/
