[Rd] eigen broken on AIX with R-devel? (PR#537)

Thomas J Vogels Thomas Vogels <tov@ece.cmu.edu>
15 Jun 2000 13:57:55 -0400


Hi, I ran the test again with the newly released version of R (1.1) and I
now get the correct eigen values.  ("make check" succeeds.)

The scary part is that I think that I also used gcc+f77 last time and
the libs weren't changed.  Maybe the scary part is that I think...

So the comments that this is compiler specific probably hold.

Thanks,
  -tom


tov@ece.cmu.edu writes:

> Hi,  I get the wrong eigen values on an AIX machine with R-devel of 5/3/00.
> 
> Here are the results:
> 
> R> m <- matrix (c(6.8, 2.4, 2.4, 8.2), nrow=2)
> R> m
>      [,1] [,2]
> [1,]  6.8  2.4
> [2,]  2.4  8.2
> R> eigen(m)
> $values
> [1] 19.281403  6.337993
> 
> $vectors
>           [,1]       [,2]
> [1,] 0.1918866  0.9967987
> [2,] 0.9967987 -0.1918866
> 
> 
> And for comparison, here is what I get on a Sun (with r-stable):

(same results now on AIX 4.3 with R 1.1.0 

> R> m <- matrix (c(6.8, 2.4, 2.4, 8.2), nrow=2)
> R> eigen (m)
> $values
> [1] 10  5
> 
> $vectors
>      [,1] [,2]
> [1,]  0.6  0.8
> [2,]  0.8 -0.6

-- 
mailto:tov@ece.cmu.edu (Tom Vogels)   Tel: (412) 268-6638   FAX: -3204
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