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Eva provides good advice on this topic but this is a bit misguided. If
you save a scalar (such as r(mean) from -su-) to a local you get
scalars:
r(N) = 74
r(sum_w) = 74
r(mean) = 6165.256756756757
. local mu = r(mean)
. di "`mu'"
6165.256756756757
You can even do arithmetic:
. local mu = `mu' + 1
. di "`mu'"
6166.256756756757
What is happening is that the scalar is storing, with maximum
precision, the numeric value as a binary number. The local is taking
that binary number's decimal representation and storing it as a
string, so that when I ask for the value of "mu" I get the full
number of digits stored therein. As is evident here, it clearly is not
the case that the local is losing digits of precision. But as Eva
suggests, if you're trying to store numbers, storing them as scalars
(as -su- does) rather than locals makes sense. Just be careful with
their names so you do not collide with other objects in the same
namespace.
Kit Baum, Boston College Economics and DIW Berlin
http://ideas.repec.org/e/pba1.html
An Introduction to Modern Econometrics Using Stata:
http://www.stata-press.com/books/imeus.html
On Oct 4, 2008, at 2:33 AM, Eva wrote:
Note also the availability of scalars (-help scalar-) which can save
numbers in higher precision than local macros.
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