Matthias Greiner
> Using
>
> . do "... \square.do"
>
> . program define square
> 1. version 7.0
> 2. gettoken n 0 : 0, parse(" ,")
> 3. local nsquared1=`n'^2
> 4. local nsquared2=(`n'*`n')
> 5. di "`nsquared1' `nsquared2'"
> 6. end
> .
> end of do-file
>
> I observe the following misbehaviour of the power operator "^2"
>
> . square -2
> -4 4
>
> The example is for illustration -- the problem occurs in a
> real programme,
> where the negative value n is a result of internal (and correct)
> calculations. I am puzzled because I never observed this before.
>
Nick Winter and Hakon Finne have already identified
the problem clearly.
There is a fuller exposition at
I coded 'a'2 and got the wrong sign. Why?
http://www.stata.com/support/faqs/lang/macpow.html
Nick
[email protected]
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