[R] number point under-flow

[Uwe Ligges]

Roger D. Peng wrote:

> Did you compile with gcc-2.96?  I think there were some problems with 
> the floating point arithmetic with that compiler (at least for the 
> earlier versions released by Red Hat).

Not (solely) a gcc-2.96 bug, since we get

   phyper(24, 514, 5961-514, 53, lower.tail=F)
[1] -3.325784e-12

on Windows compiled with gcc-3.3.1

Uwe Ligges


> -roger
> 
> Arne.Muller at aventis.com wrote:
> 
>> Hello,
>>
>> I've come across the following situation in R-1.8.1 (compile + running 
>> under
>> RedHat 7.1):
>>
>>
>>> phyper(24, 514, 5961-514, 53, lower.tail=T)
>>
>>
>> [1] 1
>>
>>> phyper(24, 514, 5961-514, 53, lower.tail=F)
>>
>>
>> [1] -1.037310e-11
>>
>> I'd expect the later to be 0 or some very small positive number. Is 
>> this a
>> number under-flow of the calculation? Do you think I'm safe if I just 
>> set the
>> result to 0 in these cases?
>>
>>     kind regards,
>>
>>     Arne
>>
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> 
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