How about something along the following lines? (untested!!)
Instead of
gen `yh'= exp($A) + sum(from n =1 to 34)[n*cos($B)+ (n-1)*tan($B)] -2 in
1
try
tempvar X
egen `X' = (_n<=34)*sum( _n*cos($B) + _n-1*tan($B) )
gen `yh'= exp($A) + `X' -2 in 1
Assuming your data set has at least 34 obs in it, the idea is to use the
egen to calculate the sum
Stephen
-------------------------------------------------------------
Professor Stephen P. Jenkins <[email protected]>
Institute for Social and Economic Research
University of Essex, Colchester CO4 3SQ, U.K.
Tel: +44 1206 873374. Fax: +44 1206 873151.
http://www.iser.essex.ac.uk
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of
> Andreas Aschbacher
> Sent: 30 March 2004 09:37
> To: [email protected]
> Subject: st: sum in nonlinear equations
>
>
> Dear fellows !
> is there apossibility to write line *9* in Stata-code -
> I have written it in pseudocode,please look at line 9
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> . capture program drop nlfaq
>
> . program nlfaq
> 1. if "`1'" == "?" {
> 2. global S_1 " A B C"
> 3. global A=1
> 4. global B=1
> 5. global C=1
> 6. exit
> 7. }
> 8. tempvar yh
> 9. gen `yh'= exp($A) + sum(from n =1 to 34)[n*cos($B)+
> (n-1)*tan($B)] -
> 2 in 1
> 10. replace `yh'= $A/$B +$C^2-log($B) in 2
> 11. replace `yh'= $A/($A+$B+$C)- sin($C) in 3
> 12. replace `1' = `yh'
> 13.
> . end
>
> . nl faq y ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> this would be very necessary for me because I could
> deconvolute with Stata using modified Simpsonrule for
> computing integrals. using LevenbergMarquardt with Stata is
> possible in physics,convolution- computing is very easy
> too,the way back namely deconvolution would be possible too
> if I could compute this sum
>
> any help would be appreciated very much
> andreas aschbacher,greetings to all fanatic Stata users in the world
>
> --
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