st: AW: RE: scalar and calculations

["Martin Weiss" <martin.weiss1@gmx.de>]

<> 


Tomas may also want to stay alert to the problem discussed in
http://www.stata-journal.com/sjpdf.html?articlenum=dm0021




HTH
Martin


-----Ursprüngliche Nachricht-----
Von: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Nick Cox
Gesendet: Freitag, 16. April 2010 16:17
An: statalist@hsphsun2.harvard.edu
Betreff: st: RE: scalar and calculations

You are confusing scalars with their names, which may or may not be
temporary. 

Scalars need not have temporary names. In your case the scalar has a
permanent name, v, which you assigned to it. 

You could use v rather than `v' throughout -- so long as no variable is
named, or unambiguously abbreviates to, v.

Alternatively, and better, 

tempname v 
scalar `v' = 

Conversely, the `v' notation suggests to Stata that it should find something
with the temporary name specified, and in your case there is no such beast. 

Nick 
n.j.cox@durham.ac.uk 

Tomas Lind

Scalar can´t do calculations?


I am trying to do some simulations. In a simplified version of my code, this
works (part of code shown) where n is sample size:

scalar v = r(mean) 
return scalar v2 = (`v'+2) * `n'		// No error messages

But this does not work:
scalar v = r(mean) 
return scalar v2 = (`v'^2) * `n'		// Error, ^2 invalid name


This is part of the full code and I get an error for ^2.
summarize ln_large
scalar v = (r(sd)^2)/2
return scalar mlk = exp(r(mean)) * (1 + ((`n'-1)/`n') +
 ( ((`n'-1)^3)/(`n'^2*(`n'+1)*2*1 ) ) * (`v'^2/(    2*1) )  +
 ( ((`n'-1)^5)/(`n'^3*(`n'+1)*(`n'+3)*3*2*1 ) ) * (`v'^3/(  3*2*1) )  + 
 ( ((`n'-1)^7)/(`n'^4*(`n'+1)*(`n'+3)*(`n'+5)*4*3*2*1 ) ) * (`v'^4/(4*3*2*1)
) )

How shall I do to calculate the value for mlk?


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