R devel - Sep 1998 - seq --> Dealing with bugs in R, etc.

>>>>> "Jim" == Jim Lindsey
<jlindsey@alpha.luc.ac.be> writes
   in a private mail to me

    Jim> That bug in seq() really has shaken my faith in R. How
    Jim> many other known bugs are there that we on r-help are not informed
    Jim> of and which can falsify our statistical analyses??? It is
    Jim> imperative that patches for such things be made immediately
    Jim> available on r-help. Jim

I think the answer to this should be known/discussed more widely:

Jim, you are right: 
The patch to seq(.) should have made it to  R-help.
[[actually in the mean time, the issue was raised that my patch
  was much more than was needed for dealing with rounding errors
  in the  seq(.,., by= ) case
]].

Note that there *are* other known bugs, all(?) of which being 
of much more low-level (and ``deeper'') nature.
Things like 
	mode(NULL)  -> "list"
		[now (in 0.63 "unstable") corrected to  "NULL"].

For bug submitting & tracking, 
Peter Dalgaard has recently setup a web place  
	[and 0.63-unstable has function  bug.report()]
were bug can be reported ``discussed'', etc. : 
	http://R-bugs.biostat.ku.dk/R

It is also available from CRAN's main page

---
There are also plans to regularly post a list of these bugs to R-devel (not
R-help!). 

If we know of a bug that affects high-level functions in bad way,
we usually *do* post to R-help....

R-devel is also for people who develop considerable amount of own R
functions.   There are things on R-devel which are not of interest to all
of the subscribers, but I think CRAN contributors like you should be part!

Martin

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> Date: Tue, 15 Sep 1998 09:44:15 +0200
> From: Martin Maechler <maechler@stat.math.ethz.ch>
> To: jlindsey@alpha.luc.ac.be
> CC: R-devel@stat.math.ethz.ch
> Subject: Re: seq  --> Dealing with bugs in R, etc.
> 
> >>>>> "Jim" == Jim Lindsey
<jlindsey@alpha.luc.ac.be> writes
> 
>    in a private mail to me
> 
>     Jim> That bug in seq() really has shaken my faith in R. How
>     Jim> many other known bugs are there that we on r-help are not
informed
>     Jim> of and which can falsify our statistical analyses??? It is
>     Jim> imperative that patches for such things be made immediately
>     Jim> available on r-help. Jim
 
How does that `falsify a statistical analysis'? It just gives a vector
that is slightly too long. I cannot imagine this is the worst bug
in R right now.
> I think the answer to this should be known/discussed more widely:
> 
> Jim, you are right: 
> The patch to seq(.) should have made it to  R-help.
> [[actually in the mean time, the issue was raised that my patch
>   was much more than was needed for dealing with rounding errors
>   in the  seq(.,., by= ) case
> ]].
> 
> Note that there *are* other known bugs, all(?) of which being 
> of much more low-level (and ``deeper'') nature.
Not all: e.g. mahalanobis() gives incorrect results almost all the 
time in 0.62.3, and glm with offset is wrong often too (and both
those are in the R-bugs database).

And seq gave wrong answers in the previous releases too: 
seq(1.575, 5.125, by=0.05) was wrong. At least the simpler uses are
now correct. 

I do think R-bugs is the right place for bugs.

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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