Re: [Discuss-gnuradio] Non-deterministic behavior in GNU Radio

That's the problem. If a set_output_multiple(4) in added to the
constructor in divide_cc_impl.cc, it solves the issue.

Ron

On 10/03/2018 06:42 AM, Ron Economos wrote:
> Well, I guess it's not really a bug. Most likely it has to do with the
> accuracy difference between the x86 intrinsics and the C library. If
> you look at the code in volk_32fc_x2_divide_32fc.h, the remaining
> points that are not a multiple of four are calculated with the C
> library. If the points from one run that are calculated with the C
> library line up with points calculated with intrinsics in the next
> run, there can be a mismatch.
>
> Ron
>
> On 10/03/2018 06:27 AM, Ron Economos wrote:
>> It's a VOLK bug. Go into ~/.volk/volk_profile and change the
>> volk_32fc_x2_divide_32fc line to generic. That fixes the issue here.
>>
>> Ron
>>
>>
>> On 10/03/2018 05:46 AM, Piotr Krysik wrote:
>>> Hi all,
>>>
>>> I simplified the flowgraph a bit and prepared a script that runs it
>>> twice and compares the results.
>>>
>>> https://imgur.com/a/CSjOeLc
>>>
>>> In short something is wrong indeed.
>>> Almost after every run of the script I get results with differences.
>>>
>>> I tested it on GNU Radio  3.7.12.0, I'm compiling the most fresh
>>> version
>>> now.
>>>
>>> Best Regards,
>>> Piotr Krysik
>>>
>>> W dniu 03.10.2018 o 06:55, Reiichiro Nakano pisze:
>>>> Here's an updated flowgraph where you don't need a separate file
>>>> source. Just run the flowgraph twice for a few seconds each. You'll
>>>> likely get different file sizes but `cmp` doesn't care, it'll still
>>>> show the first differing byte which should still prove the bug exists.
>>>>
>>>>
>>
>> _______________________________________________
>> Discuss-gnuradio mailing list
>> Discuss-gnuradio@gnu.org
>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
>
> _______________________________________________
> Discuss-gnuradio mailing list
> Discuss-gnuradio@gnu.org
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

_______________________________________________
Discuss-gnuradio mailing list
Discuss-gnuradio@gnu.org
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio