On 04/05/2011 04:53 PM, Robert Bradshaw wrote:
On Tue, Apr 5, 2011 at 3:51 AM, Stefan Behnel<stefan...@behnel.de> wrote:
mark florisson, 04.04.2011 21:26:
For clarity, I'll add an example:
def f(np.ndarray[double] x, double alpha):
cdef double s = 0
cdef double tmp = 2
cdef double other = 6.6
with nogil:
for i in prange(x.shape[0]):
# reading 'tmp' makes it firstprivate in addition to
lastprivate
# 'other' is only ever read, so it's shared
printf("%lf %lf %lf\n", tmp, s, other)
So, adding a printf() to your code can change the semantics of your
variables? That sounds like a really bad design to me.
That's what I was thinking. Basically, if you do an inlace operation,
then it's a reduction variable, no matter what else you do to it
(including possibly a direct assignment, though we could make that a
compile-time error).
-1, I think that's too obscure. Not being able to use inplace operators
for certain variables will be at the very least be nagging.
I think we need to explicitly declare something. Either a simple
prange(..., reduce="s:+"), or all-out declaration of thread-local variables.
Reduction isn't *that* common, so perhaps that is what should be
explicit, unlike my other proposal...
Dag
_______________________________________________
cython-devel mailing list
cython-devel@python.org
http://mail.python.org/mailman/listinfo/cython-devel
