Re: [Discuss-gnuradio] Updating variable by passing message

[Marcus Müller]

Hi Mohammad,

this sounds like a wise architecture, using a message to update settings.

To answer your question:

> how i can update a variable block value in python code , is that
possible at all ?

As you noticed, yes, that's possible, because the GUI sliders etc. do that!
However, it only works because these are actually living directly in the
top_block python code.

What you **can** do is write a python block, which, as a parameter,
takes a reference to the top_block (or hier block) which it "lives" in,
and stores it in a class member.

Then you can call .set_variablename(value) on that in your message handler.

I do **not** recommend that, however. It breaks the inherent thread
safety of message passing, makes a large detour through python that will
cost a lot of copies and unnecessary type conversions "under the hood"...


Instead, better simply go and improve the FFT Filter! Add a message port
that accepts new taps! I think we'd all love to see that becoming a
feature, so if you can, please make that change and contribute it to GNU
Radio! Also, it's less work than writing the python block that I
mentioned above.

Best regards,
Marcus


On 12.08.2017 11:51, mohammad nejati wrote:
> Hi ,
> I want to update taps in "FFT FILTER" block in run time , i have a
> block that can send this taps as a message every 1 secound . i write
> an python block witch get this message what i want to do is get this
> message and update value of a variable block wich is used in FFT
> FILTER . but i dont know how i can update a variable block value in
> python code , is that possible at all ?
>
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

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