"Shi, Tao" <[EMAIL PROTECTED]> writes: > Hi, Ted: > > I guess this problem is platform-dependent. I just tied it on a R > 1.6.1 runing on Win2K, it gave me two different p values. But when I > tried it on R1.7.0 on a Linux Server, I got the similar result as > you did. I have filed a bug-report as Peter suggested.
And to add to the confusion, I checked it on r-devel (1.8.0-pre) on Redhat Linux, so it is likely to be compiler dependent too. [As we have seen in another thread, you cannot trust "==" with floating point operations. There are cases where you don't even get x==y when x and y are computed in the exact same way! Optimizing compilers will do that to you quite easily. With Intel chips, the typical issue is that a double is stored in 8 bytes but the FPU uses 10 bytes internally. Generally, this increases precision, but you can end up comparing a value to a truncated value of itself if one instance is stored in memory and the other is in an FPU register.] -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
