Re: [Discuss-gnuradio] Re: How the valve block works

[Alexandru Csete]

On Sat, Jan 8, 2011 at 6:31 PM, Patrick Strasser
<address@hidden> wrote:
> schrieb Josh Blum am 2011-01-08 05:29:
>>
>>> Just found out that the selector block fits my requirements much better.
>>> But do I have the same behaviour here again?
>>>
>>
>> The valve is implemented with the selector.
>
> Thanks.
>
> What would be the best way to disable a branch of the flow graph, so
> that the disabled path is stopped/starved/drained/disabled? I do not
> care too much about stale data in buffers, I just want to get rid of the
> unnecessary processing power that is consumed by the path branch. If
> this is not possible in grc, I'd take the generated source and modify
> it, no big deal.

Hi Patrick,

The only way I know of to disable a block is to disconnect its inputs
and outputs from the rest of the graph. GRC can not do that so you
will have to edit the python code. You have to suspend execution
during reconfiguration:
http://gnuradio.org/redmine/wiki/gnuradio/TutorialsWritePythonApplications#Controlling-flow-graphs
I usually do:
self.lock()
self.disconnect(A,B1,C)
self.connect(A,B2,C)
self.unlock()

B1 will be disconnected but will still exist and you can use it again later.

If you want to disable a whole branch with several blocks, I think you
will have to break all connections within the branch and not just he
input/output of the branch (I am not sure about this though). You can
of course put the branch in a hier block in which case you only have
to disconnect one block.

Alex