Re: [Discuss-gnuradio] problem understanding the ninput_items/noutput_items

Makes perfect sense, thanks!!!

On 11/07/2017 08:03 AM, Michael Dickens wrote:
> Hi Jason - This behavior is normal. If you're curious, read through the
> code in gnuradio-runtime/lib/block_executor.cc, specifically here: <
> https://github.com/gnuradio/gnuradio/blob/master/gnuradio-runtime/lib/block_executor.cc#L395
>> . Note the comments: "not enough input on input[i]" and "if we can, try
> reducing the size of our output request" coupled with dividing the
> number of output items to test for (in ::forecast). The implication is
> that some upstream block isn't providing data as fast as this block is
> consuming it. So it's not the downstream null sink that's causing this
> behavior, it's whatever is upstream. Hope this helps! - MLD
>
> On Mon, Nov 6, 2017, at 12:46 PM, Jason Matusiak wrote:
>> I am having a problem understanding something simple in my general_work
>> function.
>>
>> I have a forecast function, but I seem to get different sizes for
>> ninput_items/noutput_items in general_work.  What I currently do is find
>> the minimum of the two values and work off of that: int min_items =
>> (ninput_items[0] < noutput_items) ? ninput_items[0] : noutput_items;.
>>
>> In my mind that makes sense, but if I print out the values of
>> ninput_items/noutput_items, I see something I think is odd.  Over and
>> over it looks like this (where this is ninput_items/noutput_items=
>> min(ninput_items,noutput_items):
>> 2044/1024=1024
>> 1020/512=512
>> 508/256=256
>> 252/128=128
>> 124/64=64
>> 60/32=32
>> 28/16=16
>> 12/8=8
>> 4/4=4
>> 2044/1024=1024
>> 1020/512=512
>> 508/256=256
>> 252/128=128
>> 124/64=64
>> 60/32=32
>> 28/16=16
>> 12/8=8
>> 4/4=4
>>
>> Is this divide-by-two on the output port action what is supposed to
>> happen?  I don't understand why it keeps dropping and then jumps up in
>> size again.  I am driving a null sink, so it should be able to keep up
>> no problem....

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