Mark Cox wrote:FWIW, I'm told DGESDD should be the default choice nowadays.
I am having a hard time diagnosing a DIVIDE-BY-ZERO condition when I
invoke the foreign function DGESVD (LAPACK) on OSX with arguments in .
The one thing I can think of is the peculiarities of the way FP traps are handled on OS X (last I checked, it looked like there's plenty of blame to go around). You could try
What is making the problem difficult to diagnose is:
- the problem does not occur on FreeBSD or Linux.
- the problem does not occur if I call the same function with arguments
 on exactly the same input.
- the problem does not occur on OSX when using ECL or CCL.
- the problem does not occur on OSX when I call the function in a
(sb-int:with-float-traps-masked (:overflow :underflow :inexact :invalid :divide-by-zero) [foreign call here])