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 same
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
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
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
see the R FAQ Why
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
log2(2^3) - 3
[1]
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(2^29)-29
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?
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 less
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
log2(2^3) - 3
[1]
