Unexpected behavior with co_reduce

[floquet]

The co_reduce collective appears to be posting random, large number to result_image using the reference example in the gfortran documentation. A diagnostic version of the code and results are included in Stack Overflow: Fortran coarray anomaly with co_reduce.

Sample code showing compilation and execution:
co_reduce.tar.gz

[afanfa]

Thanks for reporting this. I've found the reason for this problem and I'm producing a patch (for OpenCoarrays). What I don't completely understand is why this problem hasn't come out earlier.

[rouson]

Presumably it hasn't appeared sooner because our current co_reduce unit test doesn't use the optional result_image argument. I'll add tests that include the result_image argument.

[afanfa]

Unfortunately result_image is not the problem. The patch that solves this bug breaks the co_reduce test already part of the OpenCoarrays test suite.

[rouson]

Wow. Thanks for catching this. So if the patch breaks the current co_reduce test, does that mean the current co_reduce test is incorrect.

[afanfa]

The compiler does something strange on the co_reduce test included in the test suite. I'm trying to understand why...

[afanfa]

I created a new branch called bugfix-coreduce that includes the patch. I think this is the right way to do it but I don't have enough time to investigate further. The problem with the co_reduce test case is probably due to a compiler bug.

[floquet]

Thanks for making coarrrays a reality. Really appreciate the hard work.

On Sat, Apr 16, 2016 at 6:52 PM, Alessandro Fanfarillo <
notifications@github.com> wrote:

Thanks for reporting this. I've found the reason for this problem and I'm
producing a patch (for OpenCoarrays). What I don't completely understand is
why this problem hasn't come out earlier.

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You are receiving this because you authored the thread.
Reply to this email directly or view it on GitHub
#172 (comment)

[floquet]

P.S. I hit the bug a about two months ago, but was convinced the problem
was my programming or my machine.

On Sat, Apr 16, 2016 at 6:52 PM, Alessandro Fanfarillo <
notifications@github.com> wrote:

Thanks for reporting this. I've found the reason for this problem and I'm
producing a patch (for OpenCoarrays). What I don't completely understand is
why this problem hasn't come out earlier.

—
You are receiving this because you authored the thread.
Reply to this email directly or view it on GitHub
#172 (comment)

[rouson]

@afanfa, any updates?