many thanks for all the clarifications and for the declaration of intents
for fixing qf().
For the sake of completeness I stumbled upon the behaviour of qf when
preparing statistical tables with R to be put online for my students. I
remained a bit surprised in seeing how much the results vary across
textbooks at least for the F.

Kind regards

Simone


On Thu, Jun 5, 2008 at 5:13 PM, Prof Brian Ripley <ripley@stats.ox.ac.uk>
wrote:

> On Thu, 5 Jun 2008, Simone Giannerini wrote:
>
>  Dear all,
>>
>> I found the following behaviour
>>
>>  rf(5,Inf,Inf)
>>>
>> [1] 1 1 1 1 1
>>
>> but
>>
>>  qf(0.1,Inf,Inf)
>>>
>> [1] NaN
>> Warning messages:
>> 1: In qf(0.1, Inf, Inf) : value out of range in 'lgamma'
>> 2: In qf(p, df1, df2, lower.tail, log.p) : NaNs produced
>>
>
> Could do better here.
>
>  incidentally,
>>
>>
>>  pf(1.00000000000001,Inf,Inf)
>>>
>> [1] 1
>>
>>> pf(1.0000000000000001,Inf,Inf)
>>>
>> [1] 0.5
>>
>> Is this the expected behaviour?
>>
>
> I think so. 1.0000000000000001 is the same as 1 in computer arithmetic, and
> pf(1, m, n) = 0.5 for all large m, n.
>
>
>> Thanks
>>
>> Simone
>>
>>  R.version
>>>
>>              _
>> platform       i386-pc-mingw32
>> arch           i386
>> os             mingw32
>> system         i386, mingw32
>> status         Patched
>> major          2
>> minor          7.0
>> year           2008
>> month          04
>> day            22
>> svn rev        45451
>> language       R
>> version.string R version 2.7.0 Patched (2008-04-22 r45451)
>>
>> platform       x86_64-unknown-linux-gnu
>> arch           x86_64
>> os             linux-gnu
>> system         x86_64, linux-gnu
>> status         Patched
>> major          2
>> minor          6.1
>> year           2008
>> month          01
>> day            17
>> svn rev        44036
>> language       R
>> version.string R version 2.6.1 Patched (2008-01-17 r44036)
>>
>> ______________________________________________________
>>
>> Simone Giannerini
>> Dipartimento di Scienze Statistiche "Paolo Fortunati"
>> Universita' di Bologna
>> Via delle belle arti 41 - 40126 Bologna, ITALY
>> Tel: +39 051 2098262 Fax: +39 051 232153
>> http://www2.stat.unibo.it/giannerini/
>> ______________________________________________________
>>
>>        [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-devel@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>
>>
> --
> Brian D. Ripley,                  ripley@stats.ox.ac.uk
> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/<http://www.stats.ox.ac.uk/%7Eripley/>
> University of Oxford,             Tel:  +44 1865 272861 (self)
> 1 South Parks Road,                     +44 1865 272866 (PA)
> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
>



-- 
______________________________________________________

Simone Giannerini
Dipartimento di Scienze Statistiche "Paolo Fortunati"
Universita' di Bologna
Via delle belle arti 41 - 40126 Bologna, ITALY
Tel: +39 051 2098262 Fax: +39 051 232153
http://www2.stat.unibo.it/giannerini/
______________________________________________________

	[[alternative HTML version deleted]]

