On Nov 16, 2011, at 22:08 , marco atzeri wrote:
On 11/16/2011 9:32 PM, Prof Brian Ripley wrote:
The failures are *not* minor. Please don't distribute an R linked to a
broken BLAS library. Those tests are not for fun: they came from real
errors on real problems.
Dear Brian,
I am reasonable sure that the cygwin blas library are fine, have
you any evidence that they are broken ?
The R test log just reports an issue handling NA that could be
related to cygwin difference to others platform.
I already noted similar difference on cygwin octave package.
Well, on other platforms we have
tcrossprod(x,y)
[,1] [,2] [,3]
[1,] NA NA NA
[2,] 2 1 0
x %*% t(y)
[,1] [,2] [,3]
[1,] NA NA NA
[2,] 2 1 0
so the Cygwin tcrossprod is implicitly letting 0*NA==0 (in the DGEMM
BLAS routine).
This is not what should happen according to the standards, and there
are people whose code relies on standards compliance (and that's why
the test is there).
It's also plain wrong, because in extended arithmetic, the missing
value could be Inf, and 0*Inf == NaN, so assuming that 0*anything==0
doesn't work.
-pd
