Re: [Numpy-discussion] Cython-based OpenMP-accelerated quartic polynomial solver

Sturla Molden <sturla.molden@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. S.M.