[SciPy-user] linalg.expm() Illegal Instruction Error?

Robert Kern robert.kern@gmail....
Sat Jun 13 17:23:56 CDT 2009

On Sat, Jun 13, 2009 at 10:44, Dylan Gorman<dgorman@berkeley.edu> wrote:
> Hi Folks,
> I'm having a bit of a weird problem. linalg.expm() is failing for
> matrices larger than size (51,51), and reports "Illegal instruction"
> and forces python to quit. I'm not sure where this is coming from. I
> created the following routine:
> for i in range(10,128):
>        A = random.rand(i,i)
>        B = linalg.expm(A)
>        print i
> which fails with "Illegal instruction" when you get to 51.

This happens when you use a numpy binary that was compiled to use an
ATLAS library on a CPU with more advanced SSE instructions than your
CPU. Exactly which binary did you install (please give a URL)? What is
your CPU?

Robert Kern

"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
  -- Umberto Eco

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