On Wed, Nov 11, 2015 at 8:32 AM, Stefan Wunsch <
[email protected]> wrote:

> Aaaah I solved it. Never ever write in a VOLK kernel to your input
> buffer! This throws no errors but it fails during the ctest. So I
> suppose the first test compares the output and the second one the input
> buffers?
>
> Greetings
> Stefan
>

Ah, interesting. This is something we should take up in the VOLK working
group. We don't claim or not claim that you can use the same memory for the
input and output buffers. Some kernels are known to work with these inplace
operations. Looks like this one doesn't. Perhaps just testing and knowing
which kernels do and do not support this and protect those that do not as
const (which can be easily gotten around) and saying as much in the
kernel's documentation.

Though for some reason I feel like I'm misunderstanding something. Also,
Nathan will probably have more to say on this issue.

Tom




> On 11/11/2015 01:45 PM, Stefan Wunsch wrote:
> > Hi!
> >
> > I have some issues with the (understanding of the) behaviour of the VOLK
> > test-cases (defined in kernel_tests.h).
> >
> > Each test defined in kernel_tests.h runs two times. Now I have the
> > problem that the first one succeeds but the second one fails.
> >
> > I do not understand why the icompare function (the signiture is
> > 32u_foo_32u) in run_volk_tests runs two times. What is the difference
> > between these calls?
> >
> > Btw, I am implementing a SIMD accelerated Mersenne-Twister!
> >
> > Greetings
> > Stefan
> >
> > _______________________________________________
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> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> >
>
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