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### Help needed w/ calculations

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```I need to be able to calculate the logarithm to base 2 of a number,
but I am limited to a high school education.  I am working on some
complex file compression techniques.  I also want powers, roots,
exponents and logs for another time.
```
 0
Reply maspethrose7 (119) 7/2/2010 3:05:30 PM

```On Jul 2, 5:05=A0pm, Harry Potter <maspethro...@aol.com> wrote:
> I need to be able to calculate the logarithm to base 2 of a number,
> but I am limited to a high school education. =A0I am working on some
> complex file compression techniques. =A0I also want powers, roots,
> exponents and logs for another time.

http://en.wikipedia.org/wiki/Logarithm etc.
```
 0
Reply Joe 7/2/2010 3:20:46 PM

```Harry Potter wrote:
> I need to be able to calculate the logarithm to base 2 of a number,
> but I am limited to a high school education.  I am working on some

For integer arithmetics, it can be found very easily:
floor(log_2(n))+1 is equal to the number of bits needed to store n. Basically
it is the position of the last '1' in binary representation of n when counting
from right to left.
E.g. for n=14 you need 4 bits to store that number and the value of log_2(14)
is somewhere in (3,4) interval.

If you would need precise answer, for whatever reason, then:
log_2(n)=ln(n)/ln(2)

> complex file compression techniques.  I also want powers, roots,
> exponents and logs for another time.

Then you need to find ln() and exp() implementations, those functions can be
combined to calculate powers and roots.

ytm

--
Najlepsza sygnatura to brak sygnatury.
http://bossstation.dnsalias.org/
```
 0
Reply Maciej 7/3/2010 9:38:38 AM

```On Jul 3, 5:38=A0am, Maciej Witkowiak <y...@elysium.pl.andremowe.me>
wrote:
> Harry Potter wrote:
> > I need to be able to calculate the logarithm to base 2 of a number,
> > but I am limited to a high school education. =A0I am working on some
>
> For integer arithmetics, it can be found very easily:
> floor(log_2(n))+1 is equal to the number of bits needed to store n. Basic=
ally
> it is the position of the last '1' in binary representation of n when cou=
nting
> from right to left.
> E.g. for n=3D14 you need 4 bits to store that number and the value of log=
_2(14)
> is somewhere in (3,4) interval.
>
> If you would need precise answer, for whatever reason, then:
> log_2(n)=3Dln(n)/ln(2)
>
> > complex file compression techniques. =A0I also want powers, roots,
> > exponents and logs for another time.
>
> Then you need to find ln() and exp() implementations, those functions can=
be
> combined to calculate powers and roots.
>
> ytm
>
> --
> Najlepsza sygnatura to brak sygnatury.http://bossstation.dnsalias.org/

Thank you, both of you!
```
 0
Reply Harry 7/5/2010 12:48:53 PM

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