From ligges at statistik.tu-dortmund.de  Fri Jul 24 19:56:26 2009
From: ligges at statistik.tu-dortmund.de (Uwe Ligges)
Date: Fri, 24 Jul 2009 19:56:26 +0200
Subject: [Rd] Bug in seq() (PR#13849)
In-Reply-To: <20090723193012.D69F3282EFFB@mail.pubhealth.ku.dk>
References: <20090723193012.D69F3282EFFB@mail.pubhealth.ku.dk>
Message-ID: <4A69F5CA.60303@statistik.tu-dortmund.de>

Please read how to report bugs (with recent version of R!) and read the 
FAQs (in thsi case FAQ "Why doesn't R think these numbers are equal?") 
and the mailing list archives before.

Uwe Ligges



jeremiah.cohen at gmail.com wrote:
> Full_Name: Jeremiah Cohen
> Version: 2.9.0
> OS: Windows XP
> Submission from: (NULL) (129.59.230.235)
> 
> 
> I believe there is a bug in the seq() function for certain values of the "from"
> argument. Here are examples:
> 
>> seq(-.2, .1, .1)
> [1] -0.2 -0.1  0.0  0.1
>> seq(-.3, .1, .1)
> [1] -3.000000e-01 -2.000000e-01 -1.000000e-01  5.551115e-17  1.000000e-01
>> seq(-.4, .1, .1)
> [1] -0.4 -0.3 -0.2 -0.1  0.0  0.1
>> seq(-.5, .1, .1)
> [1] -0.5 -0.4 -0.3 -0.2 -0.1  0.0  0.1
>> seq(-.6, .1, .1)
> [1] -6.000000e-01 -5.000000e-01 -4.000000e-01 -3.000000e-01 -2.000000e-01
> -1.000000e-01  1.110223e-16  1.000000e-01
>> seq(-.7, .1, .1)
> [1] -7.000000e-01 -6.000000e-01 -5.000000e-01 -4.000000e-01 -3.000000e-01
> -2.000000e-01 -1.000000e-01  1.110223e-16
> [9]  1.000000e-01
>> seq(-.8, .1, .1)
> [1] -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1  0.0  0.1
> 
> So, for example,
> 
>> which(seq(-.2, .1, .1) == 0)
> [1] 3
>> which(seq(-.3, .1, .1) == 0)
> integer(0)
> 
> Here are the results of the "version" command on my machine:
> 
> platform       i386-pc-mingw32             
> arch           i386                        
> os             mingw32                     
> system         i386, mingw32               
> status                                     
> major          2                           
> minor          9.0                         
> year           2009                        
> month          04                          
> day            17                          
> svn rev        48333                       
> language       R                           
> version.string R version 2.9.0 (2009-04-17)
> 
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel



[Rd] Bug in seq() (PR#13849)
Uwe Ligges