Dear Dat,

You are correct. When I create a new tagged stream block and connect to the
flow graph the problem was fixed. Thank you for the suggestion. I will see
how to write a similar block to handle the problem.

Damindra

On Sat, Dec 24, 2016 at 3:43 PM, Dat Luu <[email protected]> wrote:

> I think you use a set up like this * -- stream to tagged stream -- ofdm tx
> -- * and then perform event triggering (time based by sleep function?) to
> do reconfiguring? If yes, the problem is with the tagged stream block and
> stop(); the block will not add any tag to data stream it was processing
> upon stop(). Quick and dirty fix is to disconnect the current stream to
> tagged stream block, create a new one and connect it to the flow graph;
> losing data of course. I don't know the better fix, but you may have to
> mess with that tagged stream block and make your own block to handle that
> problem.
>
> On Sat, Dec 24, 2016 at 10:51 AM, Damindra Bandara <
> [email protected]> wrote:
>
>> Dear Keven,
>>
>> Please consider the following flow graph. I have done some changes to the
>> OFDM TX block and in the earlier file forgot to remove that. This file has
>> all the original GNURadio blocks and running in no GUI mode. But still the
>> problem is there. I appreciate if you could help me to figure out the
>> problem.
>>
>>
>> Thanks,
>> Damindra
>>
>> On Sat, Dec 24, 2016 at 1:39 PM, Damindra Bandara <
>> [email protected]> wrote:
>>
>>> Dear Kevin,
>>>
>>> Thank you for your response. Here are the answers to the questions you
>>> asked.
>>>
>>> Does it happen if you only stop and start the flow graph without
>>> actually changing any connections? Yes. It still gives the same error when
>>> only stop and start the flow graph.  When I do the reconfiguration without
>>> stop and start I do not get any error. However, I do not see any
>>> reconfigured parameters applied(i.e., it still runs with the previous
>>> configuration)
>>>
>>> Does it happen if you lock(), change, unlock() — instead of stop(),
>>> change, start()? Yes, still get the same error
>>>
>>> Does it happen if you do some reconfiguration but less than your
>>> application actually needs — e.g. replace a block with a newly-constructed
>>> identical block (should have no effect)? Yes, even for simpler applications
>>> that use tag streams.  (I have used the [stop--> change block --> start]
>>> and [lock --> change parameter --> unlock]  without any error before I
>>> introduce OFDM blocks and tagged streams. I started to get the error after
>>> introducing OFDM block and tagged streams.
>>>
>>> Herewith I have attached a  flow graph where I simply try to lock the
>>> flow graph print a statement and unlock it. I still get the same error.  To
>>> run please change the file name in the file source block and run the python
>>> file.
>>>
>>> If you can help me to figure the problem I really appreciate it.
>>>
>>> Best regards,
>>> Damindra
>>>
>>> On Sat, Dec 24, 2016 at 10:35 AM, Kevin Reid <[email protected]> wrote:
>>>
>>>> On Sat, Dec 24, 2016 at 9:46 AM, Damindra Bandara <
>>>> [email protected]> wrote:
>>>>>
>>>>> Also, I get the error only when I try to reconfigure a flow graph.
>>>>> Could you please let me know the correct way to reconfigure a flow graph
>>>>> when they are using tags.
>>>>>
>>>>
>>>> Both reconfiguration and tags are lesser-used features (reconfiguration
>>>> even less), and based on my experience with reconfiguration, there might
>>>> well be a bug in a particular block's interaction with reconfiguration. I
>>>> would suggest taking a troubleshooting/debugging approach to finding out
>>>> what is sufficient to cause the problem:
>>>>
>>>>    - Does it happen if you only stop and start the flow graph without
>>>>    actually changing any connections?
>>>>
>>>>    - Does it happen if you lock(), change, unlock() — instead of
>>>>    stop(), change, start()?
>>>>
>>>>    - Does it happen if you do some reconfiguration but less than your
>>>>    application actually needs — e.g. replace a block with a 
>>>> newly-constructed
>>>>    identical block (should have no effect)?
>>>>
>>>> It would be great if (if there actually is a bug here) you can narrow
>>>> it down to a simple example and file a bug report.
>>>>
>>>> I might be able to help with the narrowing down if you have some
>>>> reasonably-sized Python/GRC code you could share, as I've gone through this
>>>> process several times. (I develop a reconfiguration-heavy application.)
>>>>
>>>
>>>
>>>
>>> --
>>> Damindra Savithri Bandara,
>>> Ph.D. in Information Technology (Candidate)
>>> George Mason University,
>>> Fairfax,
>>> Virginia
>>>
>>
>>
>>
>> --
>> Damindra Savithri Bandara,
>> Ph.D. in Information Technology (Candidate)
>> George Mason University,
>> Fairfax,
>> Virginia
>>
>> _______________________________________________
>> Discuss-gnuradio mailing list
>> [email protected]
>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>
>>
>


-- 
Damindra Savithri Bandara,
Ph.D. in Information Technology (Candidate)
George Mason University,
Fairfax,
Virginia
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