What do you mean with easy?
I think that the famous book of Abramovitch "Handbook of Formula...." (maybe
the reference there... I have it in some backup file) explains that the
algorithm for the approximation of logarithm works better for base 10 than
other lower base (e, 2 or whatever). For that reason, log10 is computed and
log or ln is obtained as a second result using the property of logarithms.
Therefore the natural was added and the unnatural or common is the original.
I don't know how Stata works here (interesting question), but if you take a
regular scientific calculator you will see log10 and ln not log2 or log5...
the chip was produced in 60 (maybe before) with the 'tables' for log10.
Rodrigo.
----- Original Message -----
From: "Raphael Fraser" <raphael.fraser@gmail.com>
To: <statalist@hsphsun2.harvard.edu>
Sent: Tuesday, October 17, 2006 1:33 PM
Subject: Re: st: RE: log to the base 2
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.
>
> Nick
> n.j.cox@durham.ac.uk
>
> 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?
>
>
>
> *
> * For searches and help try:
> * http://www.stata.com/support/faqs/res/findit.html
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
>
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/