Re: How can you force the Scheduler to deliver appropriate vector size input

[George Edwards]

Hi Marcus, 

I have egg on my face! I messed up, Gnuradio works fine. I accidentally set one of the variables in the grc which contributes to the computation of the vector length incorrectly and made the size 496. Sometimes in the midst of these problems, we overlook the obvious. My mistake!

Sorry for taking up your time and the community time.

Thanks again for your feedback!

George 

On Wed, Oct 26, 2022, 5:16 AM Marcus Müller <mueller@kit.edu> wrote:

Hi George,

I can't really follow. A block in GNU Radio has a *fixed* output item size. So, the Stream
To Vector block *can* only produce items of size (448*sizeof(entry in the vector)). That
can't change!

Same with your block: it has an io_signature (you set it in the constructor), which fixes
its input size. There's nothing that could change that; unless GNU Radio really has a
*fatal* bug.

So please tell us how exactly you notice / observe this change in input vector length!

Best regards,
Marcus

On 26.10.22 03:24, George Edwards wrote:
> Hello GNURadio Community,
>
> I designed an OOT block to accept vectors of size 448 samples. In the flowgraph, my block
> is preceded a Stream-to-Vector block with the vector size set to 448 samples. My OOT block
> expects vector data that are of length 448 or multiple of 448 samples for signal
> processing. I dumped the output of my block to a file and noticed that the first 1000
> values were correct and the rest garbage. I put a print statement in the code to see the
> length of the input samples that the Scheduler provided on each iteration. I found out
> that the inputs were 496 and multiples of 496 (obviously not integer multiple of my
> vector length of 448 samples). Is there a way to force the Scheduler to deliver input data
> samples that are the exactly 448 and multiple of 448 samples (which I thought I would be
> getting by setting the vector size parameter to 448)?
>
> I am aware that the alternative may be to pad the data entering the Stream-to-Vector block
> which precedes my OOT Block with 48 dummy samples and in my signal processing remove them.
>
> I will appreciate any response that leads to me keeping the vector size at 448 and having
> the Scheduler provide input data that are of size 448 or integer multiples of 448.
>
> Regards,
> George