Message-ID: <4D3CA7F7.1030601@gmx.de>
Date: 2011-01-23T22:13:11Z
From: Marc Jekel
Subject: sensitivity logical operators in R
Hello R Fans,
Another question for the community that really frightened me today. The
following logical comparison produces a "false" as output:
t = sum((c(.7,.69,.68,.67,.66)-.5)*c(1,1,-1,-1,1))
tt = sum((c(.7,.69,.68,.67,.66)-.5)*c(1,-1,1,1,-1))
t == tt
This is really strange behavior. Most likely this has something to do
how R represents numbers internally and the possible sensitivity of a
computer? Does anyone know when this strange behavior occurs and how to
fix it?
Thank you all! This list is pleasure!!!
Marc