# Re: st: How to write a fast code to obtain a specific calculation

 From Tom Trikalinos To statalist@hsphsun2.harvard.edu Subject Re: st: How to write a fast code to obtain a specific calculation Date Wed, 18 Feb 2009 08:54:35 -0500

```look into the non-linear equation estimation

help nl

On Tue, Feb 17, 2009 at 6:53 PM, Tiago V. Pereira
<tiago.pereira@incor.usp.br> wrote:
> Dear statalisters,
>
> I usually  need to compute a value X that satifies a specific condition.
>
> A typical example is shown below. But this is only a single example, and
> ordinarily I have similar, but more complex aims.
>
> Hence, I would like to know your expert opinion on how one can make codes
> these kind of codes faster. Perhaps only Mata helps?
>
>
>
> In this example, I want to compute the value of tau^2 that imposes the
> lower limit of my confidence interval to be 0.
>
> .
> .
> .
> scalar lower_limit = 999999999
> while lower_limit>0 {
> local tau2 = `tau2'+0.0001
> cap drop T_i V_i W_i WT
> gene T_i= ln(_ES)
> gene V_i = _selogES^2
> gene W_i = 1/(V_i+`tau2')
> gene WT = W_i*T_i
> qui summ WT
> scalar sum_WT = r(sum)
> qui sum W_i
> scalar sum_W_i = r(sum)
> scalar summary_random = sum_WT/sum_W_i
> scalar lower_limit = summary_random-(1.96/sqrt(sum_W_i))
> }
>
>
> Cheers!
>
> Tiago
>
>
>
>
> *
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>
*
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```