Re: st: Could someone help me with my nl evaluation program? I update my program.

[张志强 <zhiqiangzhangnk@gmail.com>]

Dear Nick
Thanks for your advice, I learn  a lot about the nl programming in stata.
I final got my nl estimation result for my naive wage equation. The
problem is because of my data, I found there are some errors in my
dataset. As for my program,  does it can be used  for much more
complicate summation terms? DO I need to use the bootstrap to get much
more accurate estimation results for complicate project? such as the
distance term is a 2700*2700 matrix?
Thank you very much. Also I am appreciate other statalist help.
Best Wishes
ZhiqiangZhang

2014-02-01 Nick Cox <njcoxstata@gmail.com>:
> You have
>
> local dist17: word 17 of `varlist'
>
> I think you meant "word 19".
> Nick
> njcoxstata@gmail.com
>
>
> On 31 January 2014 16:46, 张志强 <zhiqiangzhangnk@gmail.com> wrote:
>> Dear Nick
>> Thank you for your advices. My naive code for 31 region code are as follows:
>> capture program drop nlwage3
>> program nlwage3
>>  version 12
>>  syntax varlist(min=33 max=33) if, at(name)
>>  local lnwage : word 1 of `varlist'
>>  local income : word 2 of `varlist'
>>  local dist1: word 3 of `varlist'
>>  local dist2: word 4 of `varlist'
>>  local dist3:word 5 of `varlist'
>>  local dist4: word 6 of `varlist'
>>  local dist5: word 7 of `varlist'
>>  local dist6: word 8 of `varlist'
>>  local dist7: word 9 of `varlist'
>>  local dist8: word 10 of `varlist'
>>  local dist9: word 11 of `varlist'
>>  local dist10: word 12 of `varlist'
>> local dist11: word 13 of `varlist'
>> local dist12: word 14 of `varlist'
>> local dist13: word 15 of `varlist'
>> local dist14: word 16 of `varlist'
>> local dist15: word 17 of `varlist'
>> local dist16: word 18 of `varlist'
>> local dist17: word 17 of `varlist'
>> local dist18: word 20 of `varlist'
>> local dist19: word 21 of `varlist'
>> local dist20: word 22 of `varlist'
>> local dist21: word 23 of `varlist'
>> local dist22: word 24 of `varlist'
>> local dist23: word 25 of `varlist'
>> local dist24: word 26 of `varlist'
>> local dist25: word 27 of `varlist'
>> local dist26: word 28 of `varlist'
>> local dist27: word 29 of `varlist'
>> local dist28: word 30 of `varlist'
>> local dist29: word 31 of `varlist'
>> local dist30: word 32 of `varlist'
>> local dist31: word 33 of `varlist'
>>
>>
>>
>>  tempname k0 k1 k2
>>  scalar `k0' = `at'[1, 1]
>>  scalar `k1' = `at'[1, 2]
>>  scalar `k2' = `at'[1, 3]
>>  tempvar eterm
>>  gen double `eterm'=`income'*exp(-1*`k2'*`dist1') ///
>>   +`income'*exp(-1*`k2'*`dist2') ///
>> +`income'*exp(-1*`k2'*`dist3') ///
>> +`income'*exp(-1*`k2'*`dist4') ///
>> +`income'*exp(-1*`k2'*`dist5') ///
>> +`income'*exp(-1*`k2'*`dist6') ///
>>      +`income'*exp(-1*`k2'*`dist7') ///
>> +`income'*exp(-1*`k2'*`dist8') ///
>> +`income'*exp(-1*`k2'*`dist9') ///
>> +`income'*exp(-1*`k2'*`dist10') ///
>> +`income'*exp(-1*`k2'*`dist11') ///
>> +`income'*exp(-1*`k2'*`dist12') ///
>> +`income'*exp(-1*`k2'*`dist13') ///
>> +`income'*exp(-1*`k2'*`dist14') ///
>> +`income'*exp(-1*`k2'*`dist15') ///
>> +`income'*exp(-1*`k2'*`dist16') ///
>> +`income'*exp(-1*`k2'*`dist17') ///
>> +`income'*exp(-1*`k2'*`dist18') ///
>> +`income'*exp(-1*`k2'*`dist19') ///
>> +`income'*exp(-1*`k2'*`dist20') ///
>> +`income'*exp(-1*`k2'*`dist21') ///
>> +`income'*exp(-1*`k2'*`dist22') ///
>> +`income'*exp(-1*`k2'*`dist23') ///
>> +`income'*exp(-1*`k2'*`dist24') ///
>> +`income'*exp(-1*`k2'*`dist25') ///
>> +`income'*exp(-1*`k2'*`dist26') ///
>> +`income'*exp(-1*`k2'*`dist27') ///
>>     +`income'*exp(-1*`k2'*`dist28') ///
>> +`income'*exp(-1*`k2'*`dist29') ///
>> +`income'*exp(-1*`k2'*`dist30') ///
>>  +`income'*exp(-1*`k2'*`dist31')  `if'
>>
>>  replace `lnwage' = `k0' +`k1'*ln(`eterm') `if'
>>  end
>> nl wage3 @ lnwage income dist1 dist2 dist3 dist4 dist5 dist6 dist7
>> dist8 dist9 dist10 dist11 dist12 dist13 dist14 dist15 dist16 dist17
>> dist18 dist19 dist20  dist21 dist22 dist23 dist24  dist25 dist26
>> dist27 dist28 dist29 dist30 dist31     , parameters(k0 k1 k2 )
>> initial(k0 10 k1 0.34 k2 0.02)
>>
>> this code return error
>> nlwage3 returned 199
>> verify that nlwage3 is a function evaluator program
>>
>> the problem is that if I reduce the dist variables to 20, this code
>> working very well.
>> Does that mean the initial value of my nl program is wrong if I
>> increase the  dist variables?
>> Is my program is suitable for estimate the summation over variables equation?
>> Is there some method to guess the initial values for converge?
>> I sincerely hope that you can help me!
>>
>> Zhiqiangzhang
>>
>> 2014-01-31 Nick Cox <njcoxstata@gmail.com>:
>>> "did not work" is difficult to evaluate here. You don't show the code
>>> you used or explain how it did not work, so hoping for good advice is
>>> optimistic. Macro length is unlikely to be an issue providing that you
>>> define your macros appropriately.
>>>
>>> What you may be experiencing is just that more complicated models with
>>> more adjustable parameters are typically (much) more difficult to fit.
>>> Nonlinear least squares is beautifully attractive when it works
>>> directly, but it may need very good guesses at parameter values to
>>> converge well even when the model is suitable.
>>>
>>> Nick
>>> njcoxstata@gmail.com
>>>
>>> On 31 January 2014 13:37, 张志强 <zhiqiangzhangnk@gmail.com> wrote:
>>>> Thanks Scott.
>>>> My program is working well if the dyadic of individual distance is
>>>> smaller than 20. is there a limitation for local macro number in nl
>>>> command in stata ?
>>>> I mean if the dist variables is larger than 20, my nl command did not work.
>>>> I sincerely hope that you can help me!
>>>>
>>>>
>>>>
>>>> 2014-01-30 Scott Merryman <scott.merryman@gmail.com>:
>>>>> It looks like the  -`if'-  is on a different line following the -gen
>>>>> double...- statement.
>>>>>
>>>>> The example below works:
>>>>>
>>>>>
>>>>> sysuse auto,clear
>>>>> gen lnprice = ln(price)
>>>>> gen lowweight = (weight < 3000)
>>>>> gen lowgear = (gear < 3)
>>>>>
>>>>> capture program drop nlwage1
>>>>> program nlwage1
>>>>>  version 12
>>>>>  syntax varlist(min=5 max=5) if, at(name)
>>>>>  local lnwage : word 1 of `varlist'
>>>>>  local income : word 2 of `varlist'
>>>>>  local dist1: word 3 of `varlist'
>>>>>  local dist2: word 4 of `varlist'
>>>>>  local dist3:word 5 of `varlist'
>>>>>  tempname k0 k1 k2
>>>>>  scalar `k0' = `at'[1, 1]
>>>>>  scalar `k1' = `at'[1, 2]
>>>>>  scalar `k2' = `at'[1, 3]
>>>>>  tempvar eterm
>>>>>  gen double `eterm'=`income'*exp(`k2'*`dist1') ///
>>>>>      +`income'*exp(`k2'*`dist2') ///
>>>>>      +`income'*exp(`k2'*`dist3') `if'
>>>>>  replace `lnwage' = `k0' +`k1'*ln(`eterm') `if'
>>>>>  end
>>>>>
>>>>>  nl wage1 @ lnprice mpg foreign lowweight lowgear, ///
>>>>>    parameters(k0 k1 k2 ) initial(k0 0.05 k1 0.02 k2 0.03)
>>>
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