Re: [Discuss-gnuradio] Custom Blocks and Number of Items Per Port

[Josh Blum]

On 08/06/2012 09:44 AM, Alexander Olihovik wrote:
> Will the unconsumed items on ports with a larger number of samples sent to
> them be buffered up automatically, or do I need to do that myself?
> i.e. If port 0 has 100 items, and port 1 has 300 items, and I consume 100
> items from each port, what happens to the remaining 200 items on port 1?
> Are they buffered automatically or dropped?
> 

nothing is dropped, its all held in the otput buffer of the upstream
block until all downstream readers have read. -j

> On Fri, Aug 3, 2012 at 6:10 PM, Josh Blum <address@hidden> wrote:
> 
>>
>>
>> On 08/03/2012 02:16 PM, Alexander Olihovik wrote:
>>> Ideally, I'd like to have 10000 items on each port every time work() is
>>> called, since my sink will be sending 10k snapshots of data to another
>>> algorithm.
>>> Right now, since I don't have that many items on each port, I'm looking
>> for
>>> the minimum number of items on all ports, saving that number of items
>> from
>>> each stream to a numpy array, and then calling consume() for that number
>> of
>>> items. Multiple calls to work() will eventually fill up the array. Is
>> this
>>> not a good way of doing this?
>>>
>>
>> That will work. There is more than 1 way to crack the egg.
>>
>> I believe that you can overload forecast to make the scheduler to the
>> work for you. To enable that call set_auto_consume(False)
>>
>> -josh
>>
>>> On Fri, Aug 3, 2012 at 3:12 PM, Martin Braun (CEL) <address@hidden
>>> wrote:
>>>
>>>> On Fri, Aug 03, 2012 at 02:23:39PM -0400, Alexander Olihovik wrote:
>>>>> It seems as if the gr_sync_block is close to what Josh Blum refers to
>> as
>>>> an
>>>>> Arbitrary Ratio Block in his Blocks Coding Guide.
>>>>
>>>> Read the guide again :)
>>>> that's not at all what it is.
>>>>
>>>> This might also help:
>>>>
>> http://gnuradio.org/redmine/projects/gnuradio/wiki/TutorialsCoreConcepts
>>>>
>>>> ...not quite finished, though.
>>>>
>>>>> Do you think if I were to use the forecast() function and make all
>>>>> ninput_items_required[i] to be the same set amount, I would always have
>>>> the
>>>>> same number of input_items[i] on each port every time the work()
>>>> function is
>>>>> called? Is it this simple?
>>>>
>>>> There should be no reason at all for wanting to have the same number of
>>>> input_items at every port. Leave that to the scheduler. Just consume
>>>> whatever items you need every time work() is called.
>>>>
>>>> MB
>>>>
>>>>
>>>>>
>>>>>
>>>>> On Fri, Aug 3, 2012 at 1:56 PM, Martin Braun (CEL) <
>> address@hidden
>>>>>
>>>>> wrote:
>>>>>
>>>>>
>>>>>     On Fri, Aug 03, 2012 at 01:38:38PM -0400, Alexander Olihovik wrote:
>>>>>     > There are a few cases when input_items[0] doesn't equal
>>>> input_items[1].
>>>>>     If say,
>>>>>     > len(input_items[0]) = 1000 and len(input_items[1]) = 1500, and I
>>>> returned
>>>>>     the
>>>>>     > smaller of the two values, 1000, what would happen to the other
>> 500
>>>>>     samples on
>>>>>     > port 1? Would they be buffered somewhere and then used the next
>>>> time the
>>>>>     work
>>>>>     > function is called?
>>>>>
>>>>>
>>>>>     Yep. The case where the len(input_items) are different is what you
>>>>>     should normally prepare for.
>>>>>
>>>>>     Are you *certain* you can't use a
>>>> gr_sync_{block,decimator,interpolator}?
>>>>>     That would make stuff much easier for you, I guess. For a start,
>> you
>>>>>     wouldn't even need to check input_items.
>>>>>
>>>>>     MB
>>>>>
>>>>>
>>>>>     >
>>>>>     >
>>>>>     > On Wed, Aug 1, 2012 at 8:40 PM, Tom Rondeau <address@hidden>
>>>> wrote:
>>>>>     >
>>>>>     >
>>>>>     >     On Wed, Aug 1, 2012 at 3:46 PM, Alexander Olihovik <
>>>>>     address@hidden>
>>>>>     >     wrote:
>>>>>     >     > Hi all!
>>>>>     >     > I'm writing a custom sink block in Python with multiple
>>>> input ports
>>>>>     of
>>>>>     >     all
>>>>>     >     > the same data type.
>>>>>     >     > I've been reading Josh's block coding guide, but I'm
>>>> confused at
>>>>>     one
>>>>>     >     point:
>>>>>     >     > The value returned by a block should be the number of items
>>>>>     produced by
>>>>>     >     that
>>>>>     >     > block.
>>>>>     >     > Is this to say that if I have multiple ports, I may return
>>>> the
>>>>>     value of
>>>>>     >     > input_items[0]?
>>>>>     >     > Or is it correct to say that I must return the sum of all
>>>>>     input_items[i],
>>>>>     >     i
>>>>>     >     > = range(number of input ports)?
>>>>>     >     >
>>>>>     >     >
>>>>>     >     > I would like to create a synchronous block where all ports
>>>> consume
>>>>>     and
>>>>>     >     > produce an equal number of items every time the work
>>>> function is
>>>>>     called.
>>>>>     >     > However, it appears that there are times when
>> input_items[0]
>>>> !=
>>>>>     >     > input_items[1] != ... != input_items[numPorts-1]
>>>>>     >     > If I were to return input_items[0], I would assume that
>> this
>>>> would
>>>>>     not
>>>>>     >     yield
>>>>>     >     > the results I expect!
>>>>>     >     >
>>>>>     >     > Any help is greatly appreciated!
>>>>>     >     >
>>>>>     >     > From,
>>>>>     >     > Alex
>>>>>     >
>>>>>     >
>>>>>     >     If you have a block with multiple input items and you want to
>>>> produce
>>>>>     >     the same number every time, noutput_items will tell you how
>>>> much you
>>>>>     >     are capable of producing on every output stream. When you
>>>> 'return
>>>>>     >     noutput_items', you are saying that you have produced that
>>>> many items
>>>>>     >     on EVERY stream.
>>>>>     >
>>>>>     >     There is another way that specifies the same thing. Each
>> block
>>>>>     >     consumes some number of samples on every input stream and
>>>> produces
>>>>>     >     some number of samples on every output stream. You can
>>>> individually
>>>>>     >     specify "produce(i, N_i)" and "consume(o, N_o)" on each input
>>>> and
>>>>>     >     output stream, respectively. In this case i is the input
>>>> stream and
>>>>>     >     N_i is the number of items consumed on that input stream and
>> o
>>>> is the
>>>>>     >     output stream and N_o is the number of items consumed on that
>>>> output
>>>>>     >     stream. When specifying your own 'produce' values, though,
>>>> make sure
>>>>>     >     to return WORKED_CALLED_PRODUCE, to tell the scheduler that
>>>> you have
>>>>>     >     done this yourself. But it sounds like you want to produce
>> the
>>>> same
>>>>>     >     amount on every stream, so you should be fine just using
>>>> 'return
>>>>>     >     nouput_items'.
>>>>>     >
>>>>>     >     Tom
>>>>>     >
>>>>>     >
>>>>>     >
>>>>>     >
>>>>>     > --
>>>>>     > Alex Olihovik
>>>>>     > University of Virginia 2013
>>>>>     > BS Electrical Engineering
>>>>>     > BS Computer Engineering
>>>>>     > address@hidden
>>>>>
>>>>>
>>>>>     > _______________________________________________
>>>>>     > Discuss-gnuradio mailing list
>>>>>     > address@hidden
>>>>>     > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>>>>
>>>>>
>>>>>     --
>>>>>     Karlsruhe Institute of Technology (KIT)
>>>>>     Communications Engineering Lab (CEL)
>>>>>
>>>>>     Dipl.-Ing. Martin Braun
>>>>>     Research Associate
>>>>>
>>>>>     Kaiserstraße 12
>>>>>     Building 05.01
>>>>>     76131 Karlsruhe
>>>>>
>>>>>     Phone: +49 721 608-43790
>>>>>     Fax: +49 721 608-46071
>>>>>     www.cel.kit.edu
>>>>>
>>>>>     KIT -- University of the State of Baden-Württemberg and
>>>>>     National Laboratory of the Helmholtz Association
>>>>>
>>>>>     _______________________________________________
>>>>>     Discuss-gnuradio mailing list
>>>>>     address@hidden
>>>>>     https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Alex Olihovik
>>>>> University of Virginia 2013
>>>>> BS Electrical Engineering
>>>>> BS Computer Engineering
>>>>> address@hidden
>>>>
>>>>> _______________________________________________
>>>>> Discuss-gnuradio mailing list
>>>>> address@hidden
>>>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>>>
>>>>
>>>> --
>>>> Karlsruhe Institute of Technology (KIT)
>>>> Communications Engineering Lab (CEL)
>>>>
>>>> Dipl.-Ing. Martin Braun
>>>> Research Associate
>>>>
>>>> Kaiserstraße 12
>>>> Building 05.01
>>>> 76131 Karlsruhe
>>>>
>>>> Phone: +49 721 608-43790
>>>> Fax: +49 721 608-46071
>>>> www.cel.kit.edu
>>>>
>>>> KIT -- University of the State of Baden-Württemberg and
>>>> National Laboratory of the Helmholtz Association
>>>>
>>>> _______________________________________________
>>>> Discuss-gnuradio mailing list
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>>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>>>
>>>>
>>>
>>>
>>>
>>>
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>>
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