# st: Re: How to solve a problem with globals

 From "Martin Weiss" To Subject st: Re: How to solve a problem with globals Date Tue, 24 Feb 2009 22:05:23 +0100

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Though your prob seems not connected to the issue of evaluation versus copying when creating a -macro-, you may still want to take a look at Nick`s http://www.stata-journal.com/article.html?article=pr0045
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HTH
Martin
_______________________
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----- Original Message ----- From: "Tiago V. Pereira" <tiago.pereira@incor.usp.br>
```To: <statalist@hsphsun2.harvard.edu>
Sent: Tuesday, February 24, 2009 7:50 PM
Subject: st: How to solve a problem with globals

```
```Dear statalisters,

Firstly, I would like to thank several statalisters for the splendid help
in my previous questions.

Now, I am having the following problem:

. global f_pA_1 = 0.5

. local i = 1

. dis \$f_pA_`i'
1

. dis \$f_pA_1
.5

Is that normal?

All the best,

Tiago

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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