On Fri, 04-Nov-2005 at 04:58PM +0100, Peter Dalgaard wrote:
|> In this particular case, it is slightly odd that we can't get an exact
|> answer for operations that could in principle be carried out using
|> integer arithmetic, but we're actually calculating log(8)/log(2).
|>
|> (Curiously, the s
On Fri, 4 Nov 2005, Thomas Lumley wrote:
> On Fri, 4 Nov 2005, Uwe Ligges wrote:
>
>> Dr Carbon wrote:
>>
>>> At the risk of being beaten about the face and body, can somebody explain
>>> why the middle example: log2(2^3); floor(log2(2^3)) is different than
>>> examples 1 and 3?
>>
>>
>> Because
>
On Fri, 4 Nov 2005, Uwe Ligges wrote:
> Dr Carbon wrote:
>
>> At the risk of being beaten about the face and body, can somebody explain
>> why the middle example: log2(2^3); floor(log2(2^3)) is different than
>> examples 1 and 3?
>
>
> Because
>
> > log2(2^3) - 3
> [1] -4.440892e-16
>
This is a
On 11/4/2005 10:58 AM, Peter Dalgaard wrote:
> Uwe Ligges <[EMAIL PROTECTED]> writes:
>
>> Dr Carbon wrote:
>>
>> > At the risk of being beaten about the face and body, can somebody explain
>> > why the middle example: log2(2^3); floor(log2(2^3)) is different than
>> > examples 1 and 3?
>>
>>
>
> In this particular case, it is slightly odd that we can't get an exact
> answer for operations that could in principle be carried out using
> integer arithmetic, but we're actually calculating log(8)/log(2).
>
> (Curiously, the same effect is not seen on Linux or Solaris until
>
> > log2(2^2
On Fri, 4 Nov 2005, Peter Dalgaard wrote:
> Uwe Ligges <[EMAIL PROTECTED]> writes:
>
>> Dr Carbon wrote:
>>
>>> At the risk of being beaten about the face and body, can somebody explain
>>> why the middle example: log2(2^3); floor(log2(2^3)) is different than
>>> examples 1 and 3?
>>
>>
>> Because
Uwe Ligges <[EMAIL PROTECTED]> writes:
> Dr Carbon wrote:
>
> > At the risk of being beaten about the face and body, can somebody explain
> > why the middle example: log2(2^3); floor(log2(2^3)) is different than
> > examples 1 and 3?
>
>
> Because
>
> > log2(2^3) - 3
> [1] -4.440892e-16
>
>
Dr Carbon wrote:
> At the risk of being beaten about the face and body, can somebody explain
> why the middle example: log2(2^3); floor(log2(2^3)) is different than
> examples 1 and 3?
Because
> log2(2^3) - 3
[1] -4.440892e-16
see the R FAQ "Why doesn't R think these numbers are equal?".
Uwe
At the risk of being beaten about the face and body, can somebody explain
why the middle example: log2(2^3); floor(log2(2^3)) is different than
examples 1 and 3?
> log2(2^2); floor(log2(2^2))
[1] 2
[1] 2
> log2(2^3); floor(log2(2^3))
[1] 3
[1] 2
> log2(2^4); floor(log2(2^4))
[1] 4
[1] 4
>
DrC
