[R] R-1.7.1 regression test failure on alphaev68-dec-osf5.1

[Peter Dalgaard BSA]

"Jeff Lewis" <jlewis at genomecorp.com> writes:

> I'm attempting to compile and install R version 1.7.1 for my statistical
> geneticists.  It seems to compile correctly -- that is, it compiles
> without errors -- but the regression test is failing in the following
> manner:
> 
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> > ## log
> > stopifnot(all.equal(log(1:10), log(1:10, exp(1))))
> > stopifnot(all.equal(log10(30), log(30, 10)))
> > stopifnot(all.equal(log2(2^pi), 2^log2(pi)))
> > stopifnot(Mod(pi - log(exp(pi*1i)) / 1i) < .Machine$double.eps)
> Error: Mod(pi - log(exp(pi * (0+1i)))/(0+1i)) < .Machine$double.eps is
> not TRUE
> Execution halted
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> 
> I'm compiling on Tru64UNIX 5.1A using DECs C and Fortran compilers and
> perl 5.6.0.  I found the above error in a file named
> 'reg-tests-1.Rout.fail'.  Any help you can give me would be most
> appreciated.

Well, it seems to be an accuracy issue, so the first question would be
what the values on both sides of the equality are (just start up R and
enter the expressions on te command line). You might have

1) Completely wrong results in complex arithmetic 
2) Slightly less than optimal accuracy
3) An underestimated .Machine$double.eps

Case 2) seems most likely, but case 3) has been observed with buggy
compilers that optimize calculations where they shouldn't.

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907