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RE: st: RE: log to the base 2


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: RE: log to the base 2
Date   Tue, 17 Oct 2006 18:51:17 +0100

What matters here is what StataCorp thought when 
choosing which functions to implement. 

The point is when to stop. If another base other than 
e and 10 were to be supplied, it would certainly be base 2. 
However, I don't think that logs base 2 are especially
often needed in statistical work -- if they were this 
would be an FAQ because many others would have the 
same question as you -- and as the work-around is easy 
I guess StataCorp decided to stop short. 

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

Raphael Fraser
 
> I thought the logs were so easy to calculate this would be a single
> standard function in Stata. I suppose you thought: if they are so easy
> to calculate why write a function.
 
> On 10/17/06, Nick Cox <n.j.cox@durham.ac.uk> wrote:

> > You hardly need any such function. The recipe
> > log(x) / log(2) or log10(x) / log10(2) will suffice.
> >
> > For example,
> >
> > . di log(8) / log(2)
> > 3
> >
> > Strictly just one log function is enough, but -log10()-
> > is a convenience for those preferring the unnatural.

Raphael Fraser

> > > I have been trying to find a function that can calculate 
> the log of a
> > > number to base 2. I can't find one. Am I missing 
> something here or am
> > > I not searching hard enough? Can any one help?
> > >
> > > I see log to base 10 and log to base e but what happen to the
> > > other bases?

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