[SciPy-User] deterministic python code which is unstable

[Pauli Virtanen]

Pauli Virtanen <pav <at> iki.fi> writes:
> Frédéric Parrenin <parrenin <at> ujf-grenoble.fr> writes:
> > Is it not possible to bug report those linear algebra libraries?
> 
> The behavior is not a bug, and not really fixable by the linear algebra
> libraries either. Modern compilers produce code that can lead to
> nondeterministic behavior under circumstances (think SSE and memory
> allocation alignment).

http://software.intel.com/sites/default/files/article/164389/fp-consistency-122712_1.pdf

i.e., the alternatives are

(i) faster execution
(ii) reproducibility of rounding error

Compilers default usually to (i).