Cython parallel prange - thread locality?

Vote count: 0

I am iterating using prange over a list like this:

from cython.parallel import  prange, threadid

cdef int tid
cdef CythonElement tEl
cdef int a, b, c

# elList: python list of CythonElement instances is passed via function call
for n in prange(nElements, schedule='dynamic', nogil=True):
    with gil:
        tEl = elList[n]
        tid =  threadid()
        a = tEl.a
        b = tEl.b
        c = tEl.c 

        print("thread {:} elnumber {:}".format(tid, tEl.elNumber))

   #nothing is done here

    with gil:
        print("thread {:} elnumber {:}".format(tid, tEl.elNumber))

    # some other computations based on a, b and c here ...

I expect an output like this:

thread 0 elnumber 1
thread 1 elnumber 2
thread 2 elnumber 3
thread 3 elnumber 4
thread 0 elnumber 1
thread 1 elnumber 2
thread 2 elnumber 3
thread 3 elnumber 4

But i get:

thread 1 elnumber 1
thread 0 elnumber 3
thread 3 elnumber 2
thread 2 elnumber 4
thread 3 elnumber 4
thread 1 elnumber 2
thread 0 elnumber 4
thread 2 elnumber 4

So, somehow the thread local variable tEl becomes overwritten across the threads? What am i doing wrong ? Thank you!

asked 20 secs ago

macmallow

Let's block ads! (Why?)

Cython parallel prange - thread locality?