[R] That dreaded floating point trap
Alexander Engelhardt
alex at chaotic-neutral.de
Thu Mar 31 14:56:49 CEST 2011
Am 31.03.2011 14:41, schrieb Sarah Goslee:
> On Thu, Mar 31, 2011 at 8:14 AM, Alexander Engelhardt
>> this helps, thank you.
>> But if this code is in a function, and some user supplies a vector, I will
>> still have to round it in the function, I guess.
>>
>> It's weird how 0.1 is different from round(0.1, digits=1) , but I don't want
>> to read that 90 page long floating point paper which was referenced
>> somewhere :)
>
>
> Or you could try the much shorter R FAQ 7.31. Turns out it
> isn't weird at all, if you are a computer.
You're a computer! :)
But yes.. the FAQ entry was where I found all.equal and the referenced
90-page-paper. But I didn't find out how to do a subset with 'somevector
> 0.4'.
I think I'll have to round the numbers every time now.. or use some
other not-so-pretty workaround like 'somevector > 0.4 - 0.05' for
0.1-binned data.
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