[R] looking for some reading on accuracy of binary computers and all.equal(); was: help for the first poster- a simple question

[Uwe Ligges]

Xuejun Qin wrote:
> Hi, there, 
> I cannot  get accurate value  for calculation.
> for example:
> ld<-sqrt(1*0.05*0.95*0.05*0.95)
> 0.05*0.95-ld=-6.938894e-18
> 0.05*0.95-ld==0 is False.
> 
> I met this problem in my program, how can I handle it. Thanks.
> 
> 
> xj.
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.


Yes, PLEASE do read the posting guide, first poster!
There you will find that there are FAQs where your first poster's 
question is already answered. And that the subject line can be used in a 
sensible manner.

Best,
Uwe Ligges