help for the first poster- a simple question
On Mon, 2008-03-03 at 12:52 -0500, 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.
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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