[R] identical values not so identical? newbie help please!

[maiya]

Hi there! 
I'm not sure I can create a minimal example of my problem, so I'm linking to
a minimal .RData file that has only two objects: obs and exp, each is a 6x9
matrix.  http://dl.dropbox.com/u/10364753/test.RData link to dropbox file 
(I hope this is acceptable mailing list etiquette!)

Here's what happens:
> obs[1, 1]
[1] 118
> exp[1, 1]
[1] 118
> obs[1, 1]-exp[1, 1]
[1] 2.842171e-14

Problem is, both obs and exp should be identical. They are the result of a
saturated loglinear model, and I've run the same code across about 400
tables, all of which result in sum(obs-exp)=0, except for this one. I can't
figure it out?

Anyway, I need help understanding why 118 and 118 are not really the same. I
appreciate some may be wary of downloading my .Rdata file (I'm on ubuntu if
that's any consolation), but I don't know how else to ask this quesiton!

Thanks!

Maja Z.



--
View this message in context: http://r.789695.n4.nabble.com/identical-values-not-so-identical-newbie-help-please-tp3346078p3346078.html
Sent from the R help mailing list archive at Nabble.com.