From: Xuejun Qin <xjq_at_chg.duhs.duke.edu>

Date: Mon, 03 Mar 2008 14:12:34 -0500

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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. Received on Mon 03 Mar 2008 - 19:20:00 GMT

Date: Mon, 03 Mar 2008 14:12:34 -0500

Thanks for all response. Here is more closer to my question, p<-0.05

ld<-sqrt(f* (1 - f) * p * (1 - p))

d <- ((1 - p) * f - ld)/(1 - p)

D d

1 -1.387779e-16 -7.304099e-18

cond1<-pmin(haplo[,1],haplo[,2])

haplo[cond1>=0,]

But the program cannot get right one, because

> On Mon, 2008-03-03 at 12:52 -0500, Xuejun Qin wrote:

*>> Hi, there,
**>> I cannot get accurate value for calculation.
**>> for example:
**>> ld<-
**>> 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.
**>
**> Answer 1:
**>
**> Read FAQ 7.31 -
**>
**> http://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-doesn_0027t-R-think-these-numbers-are-equal_003f
**>
**> Answer 2:
**>
**> Use all.equal()
**>
**>> ld<-sqrt(1*0.05*0.95*0.05*0.95)
**>> 0.05*0.95-ld
**> [1] -6.938894e-18
**>> 0.05*0.95-ld==0
**> [1] FALSE
**>> all.equal(0.05*0.95-ld, 0)
**> [1] TRUE
**>
**>>
**>>
**>> xj.
**>
**> HTH
**>
**> G
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*

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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. Received on Mon 03 Mar 2008 - 19:20:00 GMT

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