Re: [Discuss-gnuradio] How to increase the noutput_items

[Zhe Feng]

Dear Martin, 

I tried to call it in the constructor, and it's the same as call it in the work function. It didn't work as I expected. 

I was actually trying to update and adding more features to peak_detector2. There is a conditional statement below in my work function. 

if( noutput_items >= d_look_ahead) 

I tried to use set_min_noutput_items (d_look_ahead) in the constructor and in the work function. Neither of these two ways helped me satisfy the above condition. 

Best regards,

Zhe

On Wed, Apr 1, 2015 at 1:22 PM, Martin Braun <address@hidden> wrote:

I don't know the details off the top of my head, but this might be one of those functions that you can't call during work(). Have you tried calling it in the ctor?

M

On 01.04.2015 08:34, Zhe Feng wrote:

Dear Marcus,

Thanks for your comment!
I made a typo my previous post that I was going to say
"set_min_noutput_items" but I wrote "set_noutput_items". I actually used
it in the work function, but it didn't seem to function as I expected.
After reading your comment, I put it in the constructor and nothing
changed.

Best regards,
Zhe

On Wed, Apr 1, 2015 at 11:18 AM, Marcus Müller <address@hidden

<mailto:address@hiddencom>> wrote:

    Hi,
    noutput_items is what GNU Radio can maximally allow your block to
    produce, which is the free size in the output buffer, which is the input
    buffer of the next block.
    So if your block is faster than the downstream block, you will see
    exactly the behaviour you are observing. This is normal, and good.

    There's nothing the scheduler can do about this -- something
    "downstream" of your block just "backs up" the item flow, and your block
    will have to wait until whatever is downstream of it is done consuming
    input, so that there is space for output from your block again.

    You could try using set_min_noutput_items [1] in your block's
    constructor, so that GNU Radio won't even ask you to work() if there's
    not enough space available.

    Greetings,
    Marcus


    [1]
    http://gnuradio.org/doc/doxygen/classgr_1_1block.html#a65cfc579150dc4d10c6180d3365aa9a8

    On 04/01/2015 04:47 PM, Zhe Feng wrote:
     > Dear all,
     >
     > I'm experiencing a problem with the noutput_items.
     >
     > I have written a sync block which did "return" several times. I
    found the
     > noutput_items dropped exactly by the amount that I returned. For
    example, if
     > I wrote "return 10", after that, I printed noutput_items and found it
     > decreased to noutput_items -10.
     >
     > Due to this fashion, the noutput_items could decrease to a value
    that one of
     > my "if statement" isn't satisfied. In that case, several items
    wouldn't be
     > outputed so the actual size of output items is smaller than the
    size of
     > input items. Is it still a sync block?
     >
     > I tried to wait for the noutput_items to increase but it didn't
    happen. I
     > tried to use "set_noutput_items( )" or "set_output_buffer()" to
    some values
     > I wanted, but they also failed.
     >
     > So I'm asking that how to tell the scheduler effectively that I
    want to
     > increase the noutput_items?
     >
     > Thanks!
     > Best regards,
     > Zhe
     >
     >
     >
     > --
     > View this message in context:
    http://gnuradio.4.n7.nabble.com/How-to-increase-the-noutput-items-tp53075.html
     > Sent from the GnuRadio mailing list archive at Nabble.com.
     >
     > _______________________________________________
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--
Zhe Feng
Electrical Engineering: System
University of Michigan Ann Arbor
Tel: 734-834-3188




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--

Zhe Feng 

Electrical Engineering: System 

University of Michigan Ann Arbor 

Tel: 734-834-3188