[Numpy-discussion] Cython-based OpenMP-accelerated quartic polynomial solver
sturla.molden at gmail.com
Fri Oct 2 16:15:05 EDT 2015
Sturla Molden <sturla.molden at gmail.com> wrote:
> Cython actually requires that there is a shared address space, and it
> invokes something that strictly speaking has undefined behavior under the
> OpenMP standard. So thus, a prange block in Cython is expected to work
> correctly on a laptop with a multicore processor, but it is not expected to
> work correctly on a cluster.
OpenMP does not guarrantee that dereferencing a pointer in a parallel block
will dereference the same object across all processors. It only guarrantees
that the value of a shared object can be synchronized. There are many who
use OpenMP and think only in terms of threads that do this incorrectly.
Cython is actually among those.
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